Field notes: ENDURANCE

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Our first day in the field! This morning we started off by enjoying our last prepared breakfast in the McMurdo Station dining hall and then checked out of our rooms and headed down to the helo pad for our flight to the west lobe of Lake Bonney. The plan was that Peter, Bill, Kristof, Bob, Annika, Maciej and Vickie would head out to the Blood Falls campsite and start to set up the Bot House platform on the lake ice. Chris and Shilpa would join us in the field on Friday. Maciej and Annika left town on the first flight to run some errands at the Lake Bonney camp before the rest of us arrived. After we selected our helmets and weighed ourselves, the helo technicians loaded our duffel bags into the Huey and we all squished into the remaining seats. The rhythmic thud of the rotors accelerated and we were carried over the white expanse of the Ross Ice Shelf and into the stark grey granite walls of the Taylor Valley.

After the scenic 40 minute flight we arrived at the Blood Falls Camp site, named for the dark orange streaks in the iron stained glacier nearby. McMurdo carpenters had already set up two small weather haven tents for us and a couple helo sling loads of our camp gear had already been delivered that morning. We took a couple of hours to set up camp. We decided to use the smaller weather haven as a kitchen and the larger red haven as a dining room. We set up our tables and chairs, moved food into the kitchen and set up our personal tents.

A sling load and our duffel bags on the shore of Lake Bonney, at Blood Falls Camp.

After a quick lunch we walked out to the 8 diameter ice hole that Maciej and Annika melted for us last week. For a quarter mile radius around the hole, the ice was strewn with sling loads of our gear lumber, tools, drums of fuel, and the wood panels that will make up the floor of our Bot House. The first task was to unload some of the tool boxes and lumber pallets. Once we had some tape measures in hand we were ready to start real work towards building the platform. Over the course of the afternoon we surveyed out the locations for the floor supports, stopping occasionally to duck low when additional helo deliveries arrived. By evening all of the floor supports were in place. The last sling load was set on the ice just as we all crawled into our tents for the night.

Bob, Bill and Bart decide where to place the floor supports around our ice hole. A couple inches of ice have refrozen on the water surface, making it safer for us to work around the hole.

Bob and Kristof unwrap a lumber sling load on the lake ice. The yellow wings are placed on the sling loads by the helo techs to stop the load from spinning as the helicopter flies through the air.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

We returned to the floor supports we placed yesterday. To ensure that our finished floor sits level, Bill and Peter took some time to measure the height of each floor support as the others placed the 8″x8″ timbers that hold the floor panels. With their measurements, we shimmed some of the timbers with plywood to bring them to the proper height. The 8×8’s are held in place end to end by steel moment plates. We attached these and then added 2×4 spacers that keep the four rows of 8×8’s parallel.

Peter and Bill level the timbers.

The 8×8 timbers are in place and ready for the floor panels.

With the 8×8 timbers in place, our next move was to start placing floor panels. During our test-build of the Bot House in McMurdo, we learned that the floor panels are heavy (~500 lbs), but manageable when many people work together to lift them. The difference between our test build and the real thing, however, is that here we are working on the uneven and slick surface of the lake ice instead of the flat gravel yard at McMurdo. Slowly and cautiously, we inched the first few platform sections across the ice until Maciej brought our attention to another tool we have at our disposal here: the ATV. The new procedure became to have several lifters carefully place a platform section onto the bed of the ATV and then walk alongside the vehicle to make sure it didn’t slide off the bed as someone drove the ATV to the platform-in-construction. From there it was easy to transfer the section from the ATV to the 8×8’s.

Moving the floor panels with the ATV was much easier than lifting them.

As one crew moved the floor sections into place, other folks worked to line the panels up and bolt them to each other. Then the floor sections needed to be anchored to the ice. For this Peter drilled two holes into the ice at the end of each panel. The holes intersected under the surface in a V-configuration. We threaded rope through the ice holes and tied off to eye bolts in the sides of the panels. The finishing touch for the day was to secure the base frame of the tent to the edge of the floor.

Peter drills holes in the ice to anchor the platform.

A completed floor at the end of the day.

We are ready to build the tent after the bot arrives tomorrow!

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Things have been going very well with our fieldwork for the last two days—the weather has been pleasant, we made good progress on the Bot House platform and we’ve even had some tasty camp dinners in our mess tent. One could almost forget we’re in Antarctica… Well, today we got a little reminder. Late last night several of us woke up to find the walls of our tents whipping and popping in our faces, straining against the tent poles. The mild wind from yesterday has built up into violent gusts and from what we hear on the VHF radio, the weather in McMurdo is deteriorating, too. As a result, no helos are flying today and the official operations in McMurdo, helo and otherwise, will be shut down Saturday and Sunday for the Thanksgiving holiday. After all our rush, the bot won’t be delivered until Monday.

Of course in the field there is always work that needs to be done so we used our new-found free time to work on mission planning and choose the spot for our second melt hole. Lake Bonney lies in the bottom of the Taylor Valley and the lake’s shape is dictated by the valley walls. It is narrow and long, too long for us to drive the vehicle to all points in the west lobe of the lake from a single point, so we will work from two different ice holes – one close to the Taylor Glacier face and the second further east. About halfway through our fieldwork schedule we will move the bot house to the second hole but first we need to make the hole.

To initiate us as true scientists in the Dry Valleys, Peter decided that we needed to drill the pilot hole in the ice. Annika was our designated “drill sergeant” and showed us how to operate the Jiffy drill, a machine that requires two people and a drill bit 10 inches in diameter. After we drilled the hole, Peter, Maciek and John Priscu returned and helped us place a melter in our pilot hole. Someone has to return to refuel the generator here every 4 or 5 hours and in two days we should have another 8′ hole in the ice.

The trombone melter in the pilot hole we drilled.

Peter, Bill and Maciej mark the perimeter of the 8′ diameter hole we will melt out.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

In US Antarctic Program tradition, Thanksgiving is celebrated the Saturday after the actual holiday so that everyone gets a long weekend, both Saturday and Sunday off work! Of course, we are hardly the sort of people to argue with that kind of a tradition and we had an invitation from John and the folks at the Lake Bonney camp to join them for turkey dinner. Around midday we headed over to the camp on the east lobe of Lake Bonney. Most folks opted for the 20 minute ATV ride to the camp and Bill and Vickie decided to walk. Along the way they came across several mummified seals. For unknown reasons, seals and penguins occasionally wander away from the sea and travel up the Dry Valleys. A long way from home and with no chance of finding food in the barren valleys, these animals die before finding their way back. Since there are no insects to consume them and the climate is extremely dry and cold, the corpses remain remarkably intact for years.

Hiking from Blood Falls Camp to Lake Bonney camp, Vickie and Bill found several mummified seals on the ice.

The last stragglers arrived at Lake Bonney Camp just as the turkeys were coming out of the oven. Noshing away on our stuffing and sweet potatoes we admired our surroundings. Unlike our camp at Blood Falls, the Lake Bonney camp is a permanent installation that is used every season. It is larger than our camp, with several large tents in addition to personal sleeping tents and a 15′ x 40′ jamesway building which is the kitchen and community space for the group there. Also they have WiFi. It was field camp nirvana. After thoroughly enjoying the good food and good company provided by the Bonney Camp researchers we took ATVs back to Blood Falls for the night.

Everyone relaxes after Thanksgiving dinner in the Lake Bonney jamesway.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Since our next moves can only happen after the bot is delivered tomorrow, today was a natural day to just take a break. The winds continued to barrel down the valley but some folks decided to take the free time as a chance to do some hiking anyhow. The others caught up on office work, read books and drank cocoa. Around the dinner table Peter explained the origins of the incredible wind we’ve been experiencing. The Antarctic continent is shaped like a giant dome, more or less. The land in the interior of the continent is covered with a massive ice sheet over two kilometers thick and the highest elevation of this dome is around the center of the continent. During the winter the rock and ice radiate their heat out to space and temperature drops. As the land cools, the air does, too. The air grows denser as it cools and gravity starts to drive it downhill. The phenomenon is called a katabatic wind and in Antarctica they are known to be fierce, cold and persistent.

This diagram by Hannes Grobe was copied from the Wikipedia page on katabatic wind.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

In accordance with our hopes, the winds died down enough by this morning that helos were flying today. In addition to the much-anticipated delivery of the bot, we were expecting several other sling loads, including the final bits of plywood for the bot house floor and the roll-away cover for the melt hole, now referred to as the moon pool. These items arrived first thing in the morning and we wasted no time getting everything in place. The next sling load to come over the horizon was a black oval with yellow feet and flame-decaled yellow fins. Everyone scurried to pull out their cameras and hunker down behind the various large shipping crates that are scattered around the platform. With a 2000 lb sling load, a Bell 212 helo creates a tremendous amount of rotor wash and certainly a lot of noise. The physical turbulence made the emotional rush of seeing the pilot set the bot squarely down on the platform all the more exhilarating. The pilot unclipped the cable and thundered off. Now it was time to get to work.

We look on nervously as the helo lowers the bot onto our Bot House platform.

The next step on our agenda was to build the polar haven tent structure of the Bot House around the bot. We learned the procedure in McMurdo: assemble the pipe arches and walls that make up the frame of the haven; pull the insulated blankets (tarps) on the end walls; pull a liner tarp over the arches and tie it down to the floor on either side; on top of this go insulating layers over the arches; and then finally a large, weather resistant cover goes over it all. Our entire practice run in McMurdo took six hours.

Things started off well enough. Though it was slightly breezy, we made quick process in constructing the pipe frame. Two people worked from the top of some scaffolding and the rest scrambled around arranging pipes and fitting them together. Over the course of the afternoon the wind began to build, but in our concern to get a shelter built over the bot we didn’t take much notice—yet. Once the frame was together we pulled out the liner tarp and prepared to install it on the 16-foot-tall frame. We lined the tarp up on the ground along one side of the arches and tied ropes to one edge of the fabric. Then we threw the other end of each rope over the entire frame to people standing on the other side of the structure. Half of the team pulls the ropes to drag the tarp up and over the arches while the other half feeds the tarp up and manages any snags that occur. This is when we really noticed the wind. We were trying to pull the tarp from the upwind side of the structure to the downwind but the force from the wind meant that the tarp simply pressed against the pipe frame with enough pressure that it was incredibly difficult to drag it up to the peak and over. Once we did get it over the top, everything got worse. With no wall to press into, the downwind end of the tarp whipped up violently against the four ropes we had tied to it. It became a sail. Helpers jumped in to assist the rope haulers, who were nearly being whisked away on the ends of their ropes. The points where we had tied the ropes on the tarp began to rip through, giving the raging beast a greater range for its erratic motions. With the whipping and cracking of the tarp, the gusting wind, and our layers of hats and hoods, shouts and instructions were snuffed out. This was the stuff of epic sea chanteys, not field robotics. Somehow we managed to tie down, at least marginally, both sides of the tarp. Worried that the liner tarp would rip further unless we put up the end wall tarps quickly, we plunged into this next struggle. By now we had been working on the tent for about eight hours. After some time spent fighting more of the same battle with the first end wall, Peter made the call that we were in a losing battle; the wind was just too strong. The rest wearily agreed and after the equally arduous task of removing the tarps from the frame and corralling the unruly masses of fabric back into boxes for the night we dragged ourselves back to camp. Sometimes it’s just best to try again tomorrow.

Members of the team work together to construct the final pipe arches (there are 17 total) of the tent frame.

With the frame completed we begin to unroll the liner tarp on the up wind side of the structure. We plan to tie ropes to one edge and pull it over the frame to tie off on the downwind side.

This quick photo, the only one snapped during our epic battle, does little to convey the chaos of the gusting wind and the tarp that threatened to carry us all away.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

What a difference a day makes. Kristof was the first one up and about this morning and he immediately set out on a mission. He drove the ATV from our somewhat sheltered camp on the shore to our Bot House site on the ice. After a brief stop at the platform to assess the situation, he returned to camp directly to report his findings. The rest of us awoke to the sound of two cooking pots banging together and Kristof shouting, “Everybody up! The wind has died down! Let’s get to work!”

We were all still exhausted from our efforts yesterday but this news rousted us from our sleeping bags. As we hurriedly ate our breakfasts and gulped down some of Bob’s coffee we wondered, “Can we do it? Can we get the rest of the tent up before the wind kicks in again?”

We marched out to the melt hole and found that yes, it was much calmer out there. But was it enough? With trepidation we unpacked the liner tarp and once again tied on the ropes and tossed them over the frame. With the first few tugs on the ropes we found that things really were much easier. We had the liner tarp up and secured and the end walls in place in no time. We had just started to pull the middle insulating layers onto the tent when a helo carrying our carpenter friends from McMurdo arrived to help us. From there on out the Bot House was abuzz with productivity. It was difficult to even keep track of all the activities that were happening simultaneously the insulating blankets and outer cover were pulled over the tent and secured; inside, the bot’s lifting gantry and hoist were assembled; electrical outlets were installed; heaters were brought in and propane tanks were staged outside; generators were set up; communications technicians arrived and set us up with solar powered wireless internet; the crust of ice that had refrozen on the surface of the hole was melted and chipped out; stairs up to the front door were installed; shipping containers full of our equipment were sorted and the contents brought inside; and finally the shipping containers themselves were pulled in close against the outside walls and secured with cargo straps to ensure that nothing could blow away.

The gantry and hoist are set up inside our completed tent.

Maciej starts the melting coil on the refrozen cap on our melt hole.The steam generated from this made the Bot House into a sauna for a few minutes.

Once the melter punched through the frozen cap, Maciej and Johnworked on chipping out some of the ice around the sides of the hole.

The Bot House is open for business! Bob, Vickie, Shilpa, Bart and Peter (left to right) pose in front of the haven.

The commute back home after a satisfying day.

Tired but happy we plodded home slowly tonight. It was a good day.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

After our brief stint as Antarctic carpenters, we have returned to doing what we do best—working with the robot. Today we got the Bot House set up as a working mission control. The programmers set up their computers along the far wall and boxes of tools, robot batteries and spare parts were unpacked and set up on tables along the two long walls of the building. The bot and gantry dominate our workspace and setting up desk and bench space for eight programmers and technicians was a little tricky. With everything unpacked and the empty shipping cases stacked high along the walls, we set about getting the bot into working order.

First of all, the bot had to be put back together. In Texas, before we shipped the bot to the Ice, we removed the most delicate sensors and packed them in padded cases to be shipped separately. This ensured that they weren’t damaged in transport and it reduced the weight of the remaining vehicle so that it would be light enough to be flown on the helo trip from McMurdo to Lake Bonney. Now that we’re here though, all of these sensors had to go back on before we can think about putting the bot in the water.

The USBL (ultra-short baseline transceiver) and HID (high-intensity discharge)lights were just a few of the components to attach to the bot today.

As Vickie bolted each sensor back to its proper place, Shilpa and Kristof worked on some of the vehicle code. Chris and Bob assessed the bot’s giant batteries and started charging them up. Bart sorted hardware and worked on developing mission plans. When Vickie went to mount the Delta T sonar to the vehicle she noticed that the bracket that should attach the instrument to the bot wasn’t here. Talking with Bill, they realized that somehow in the rush and confusion of packing the vehicle, tools, spare parts and whatnot in Texas, the bracket they had ordered had never been delivered and thus never brought. Bill and Peter therefore designed and constructed a new mounting bracket out of some extra prototyping materials we had brought along for just this kind of thing. So far this looks like the only thing that didn’t make it to Antarctica from Texas—not bad!

Bill finds some hardware to use on a new mounting bracket for the Delta T sonar.

The team works to get the bot put back together and get the Bot House set up as a workshop/mission control.

At the end of the day, most of the vehicle is back together and we should be able to start real testing tomorrow.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we put the bot in the water. Since the vehicle hasn’t been wet since our last tests at NBL (NASA’s Neutral Buoyancy Lab) in August we wanted to check all of the electronics pods for leaks and check that all of sensors and instruments were working. The bot has traveled halfway around the world, after all. To do these checks we hung the bot from the hoist without the orange syntactic blocks we normally use to make the vehicle float. John and Peter paid particular attention to their scientific instruments on the drop sonde. They adjusted the water pump on the sonde, raising the bot out, priming the pump and lowering it again a few times to watch its behavior. With the pump in order, Chris, Shilpa and Kristof ran through the checklist of sensors and electronics: No pod leaks, sonars, DVL (Doppler Velocity Log), depth sensors, IMU (Inertial Measurement Unit), cameras, lights and so on, all working. Check, check, check…

Kristof, John, and Peter watch intently as the bot is lowered into the melt hole for the first time.

John and Peter get the Seabird pump on the drop sonde working.

One of the last few tests was to check the science payload package, the profiler. The profiler is made up of several parts. First there is the drop sonde, basically an aluminum frame with all of Peter and John’s water chemistry instruments strapped onto it. This sonde hangs from the bot by a Kevlar reinforced Ethernet cable. The cable feeds over a pulley and onto a large spool on the opposite side of the vehicle. Servo motors spin the spool to raise and lower the sonde through the different water strata in the lake. Normally, with the floatation blocks in place, we are not able to see much of the spooler functioning; only the up and down motion of the sonde is visible. Since we left the blocks off for this test we were able to watch the entire profiler in action underwater. It was satisfying to see how smoothly the level winder guided the green Ethernet cable between the spool and the pulley as it wound and unwound, raising and lowering the sonde. Several minutes into the test run, however, the spooler stopped unexpectedly. Chris noted that the software was reporting a temperature fault – it was too cold. What we found was that if we heated the electronics pod for the profiler in air with the Herman Nelson heater, the driver would function correctly, but once the pod had cooled to 10°C in the nearly freezing water, the driver would stop.

We watch from above as the spooler drum (on the right) unwinds the bright green Ethernet cable that holds the sonde (underwater on the far left).

With the bot back on the surface, Chris plugs directly into the profiler electronics pod to investigate the servo motor malfunction while Kristof looks on.

Of course we had considered the effects of Antarctic temperatures on the vehicle before. We wondered if such cold water would cause equipment malfunctions. In February we operated the bot under ice in Lake Mendota in Madison, Wisconsin. Those tests identified a problem with the electronics that control the thrusters. We later traced that problem back to some poorly soldered connections – a slip in quality control from the manufacturer. The faulty electronics were immediately replaced and the bot suffered no further problems from the cold. But during the February tests in Wisconsin the profiler was still in the design phase; it didn’t exist and thus couldn’t be cold tested. So what exactly is the problem? Is there a way we can fix it in the software settings, a minimum temperature parameter we can change to allow the servos to run at a lower temperature? There isn’t anything about it in the servos’ manual and, given the time difference between here and the States, we’ll have to wait until morning to ask the manufacturer.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

The first people bringing their breakfasts into our camp mess tent this morning found Bart already on the phone with the servo driver manufacturer. Fortunately, when the comm techs set us up for internet, they also gave us a VOIP phone. After breakfast we tore ourselves away from eavesdropping on Bart’s conversation with tech support to start work out in the Bot House. Just because the profiler is temporarily stalled doesn’t mean we can’t proceed with other tests, so the plan of the day was to put the bot in the water with the syntactic on and take it for its first Antarctic swim.

Before taking the bot down under the ice, we wanted to make sure that the bottom perimeter of the ice hole was snag free. The lake ice is about 3 meters thick and the level of the lake water in the melt hole is about 30 centimeters below the ice surface. The other 2.7 meters of the hole is underwater and this makes it difficult for us to judge if the wall surface is smooth or jagged. To give us a definitive answer, Peter decided to do an ice dive and have a look. As he donned all of the gear associated with ice diving in Antarctica—layers of fleece, a drysuit, dry gloves, and a full face mask—Vickie hooked up his air supply. In these kinds of ice dives, it is nice to keep the scuba tanks in the warm air at the surface and run long hoses from the tanks to the diver’s full face mask. This keeps the tanks and first stage regulators warm, making the dive safer and more enjoyable. The full face mask includes a comm unit so we could talk to Peter during his dive. He took an ice chipper bar down and busted off all of the jagged corners at the bottom of the ice hole.

Once the melt hole was prepared it was time to get the bot ready to swim. We put the syntactic blocks on, lifted the vehicle with the hoist and set it in the water. To make the bot as power-efficient as possible, we always ballast and trim the vehicle. To ballast, we add or remove lead weights to the bot to make it neutrally buoyant, so that without hooks attached it floats just under the surface of the water and neither sinks nor rises. To trim the bot we place the lead weights we’re using for ballast in specific locations on the bot’s frame so that it sits level in the water. The whole process is a little time consuming but a neutrally buoyant and well-trimmed bot won’t use much battery power for thrusting, so it is important to get it just right. In our previous tests in tanks or at the Quarries in Austin, it was easy to add and remove lead because you could just lean over the vehicle. Here, however, there is about a meter drop from the top of the platform to the water level, where the vehicle is floating, and you would have to lean out horizontally as well to work with the ballast. Since we didn’t want to drop either a person or our lead weights into the icy water, Vickie rigged a climbing rope to the gantry and, wearing a harness and using climbing ascenders, hung just above the robot to adjust the lead weights more easily.

We put the orange syntactic blocks onto the vehicle to provide flotation.

Vickie gets on rope to ballast the vehicle and get the buoyancy just right.

Once we felt confident that the vehicle was ballasted properly, Kristof, Shilpa and Chris took their seats at the mission control table and drove the vehicle down and under the ice for the first time.

“The ice is smooth!” Shilpa reported.

This was a relief. The top surface of the lake ice is anything but smooth: it is scalloped and cracked with plateaus and valleys and in places can vary in height by half a meter. So naturally we wondered about the underside of the ice. We hoped it would be smooth because it would make navigation easier and it would be less likely for our fiber optic line to become ensnared. We all crowded around the monitor displaying the view of the horizontal-facing camera. Yes, the ice was smooth as glass.

We motored the bot around under the ice testing the various sensors in action. After a while we noticed that some of the sensors that use sonar elements started to drop out and we didn’t know why. We brought the vehicle back to the surface to check it out. As the bot rose up through the hole we noticed that it looked different, kind of…fuzzy. Also, it was too buoyant. At the end of its ascent, the bot was riding almost 2 inches higher in the water than it had when we ballasted it half an hour before. Looking closer we learned that the white “fuzz” we were seeing on the bot was actually thousands and thousands of tiny bubbles coating the entire exterior of the vehicle.

The white speckles and fuzz on the bot in this photo are actually thousands of tiny, trouble-making microbubbles.

The lake water is supersaturated in dissolved gases and as the bot moved through the water, some of this gas was apparently coming out of solution and forming these microbubbles on the robot’s surfaces. The microbubbles were making the bot significantly more buoyant and were interfering with the acoustics of the sonar transducers. We’ve never had the bot in such gas-rich waters before and didn’t predict this kind of problem.

While we found this surprise to be another puzzle we’d have to deal with, Peter reminded us all that this is the kind of stuff we are here to learn about. There are two parts to the Endurance mission here in Antarctica: one is to collect data from Lake Bonney and the other is to develop some of the technology that an AUV on Europa would use. In this way, our fieldwork here is proving to be a good analog for a mission on Europa. The exploration of Europa is bound to contain some surprises, just like our exploration of Lake Bonney and the microbubbles. The more we can learn about possible issues like these in the experimental phase here on Earth, the better we could design an AUV for alien environments.

Our attempt at a quick fix for the microbubbles on the sonars was to take a small amount of Simple Green hand cleaner and rub it over the sonar faces. This seems to keep the bubbles from forming on these surfaces but we might be able to find a better substance to act as a surfactant here. To counter the extra lift given by the bubbles, for now we just threw an extra pound of lead on the vehicle.

We took the bot back down under the ice for some more tests. For one thing, we wanted to test one of our bot recovery procedures. Now that we knew that the underside of the ice was smooth, we figured that if the bot were to die, that is, lose communications with mission control or run out of battery power, we could pull it back in by hand by tugging on the fiber optic line we use to communicate with the bot’s cPCI (the bot’s main computer). To make sure, we did a practice run of physically pulling the bot back in with an extra safety cord we had tied on. It worked very easily, so we know that in a crisis we have a way to get the bot back.

During this emergency practice, we had the upward-looking camera on, and were displaying its images on one of the mission control monitors. The upward-looking cam is at the top of the bot and faces directly up. Normally we would only use it for visual homing to help the bot return to the melt hole at the end of a mission. What we didn’t expect is the kind of images we would see while the bot was just running around under the ice. We found that the ice was amazingly clear and that a lot of sunlight came through. There are thousands of bubbles in the ice. Some bubbles contain sediment that was blown onto the ice from the land and frozen in, some bubbles are white and clear. They form columns going from the bottom towards the top. It was beautiful and Peter added enthusiastically that the views from this upward camera were a source of data that no one had recognized before. The ice was clear enough that we could even tell when we had crossed under the Bot House floor.

When we finished the remaining tests for the day we pulled the bot up for the night, put the batteries on charge and went back for dinner.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today’s testing schedule included doing some ground truthing of the navigation programs and to test our recovery beacon. Happily, it was easy to do both at the same time, since we could use the recovery beacon to locate the bot and verify if it actually navigated to the points it was programmed to go to. We sent the bot down under the ice and gave it some coordinates to drive to about 10 meters away from the Bot House. Bill and Vickie, meanwhile, suited up and went outside with the loop antennas.

Our recovery beacon is a meter-long cylinder that hangs inside the bot frame and produces a magnetic field. The field can be sensed above the ice by a loop antenna, essentially a coil of wire about half a meter in diameter. The loop antenna plugs into a receiver box and the receiver box has a set of headphones. The operator wears the headphones and can hear the signal. When the signal goes null, or makes no noise, then the loop is pointed directly at the robot. When there is a loud tone then the loop is pointed away from the bot. With two people using loop antennas, it is a simple matter to zero in on the beacon.

When mission control radioed that the bot had reached its waypoint and stopped, Vickie and Bill located the bot and marked the spot with an ice screw. A GPS check confirmed that the bot appeared to be navigating correctly. Good news!

Kristof, Shilpa, and Chris track the bot’s progress from mission control.

The next thing Peter wanted to check on was a mystery object stuck in the lake. Several researchers have worked in Lake Bonney over the years and occasionally the equipment from their various experiments—ropes, sediment traps, stakes, etc.—is lost or forgotten in the lake ice. One of our biggest fears is that Endurance will run into one of these objects dangling below the bottom surface of the ice and get the fiber optic snared. When we chose the site for our Bot House, Maciej found some crossed bamboo stakes lying on the ice nearby. It turned out that there was a string tied to them and some sort of object, one of these old experiments, dangling from the string in the water. We navigated to where we calculated the bamboo stakes to be and, approaching carefully, looked at this mystery obstacle through the forward looking camera. We could see some sort of dumbbell-shaped object but couldn’t tell what it was. Maciej then melted the object out of the ice. When Peter returned to the Bot House carrying the retrieved object we all crowded around. It was much smaller than it looked on the screen and no one had any idea what it was, just that it was corroded and crusted with salt that had precipitated onto it from the salty lake. While it remains a mystery, we’re just happy to have this obstacle removed from our path.

Peter displays the mystery experiment pulled out of the lake. The white goop on the body of the thingis salt from the lake. We salvaged the square of Plexiglas for use as a prototyping material later -you never know what you’ll need in the field.

While today went well, the end of the day was still a bit of a bummer. Bob and Annika left on a helo flight this afternoon and after a day or two in MacTown they’ll be heading off to holidays in New Zealand. Thanks for your help guys, we’ll miss you!

One last shot of the team before Bob and Annika leave. From left to right: Bill, Chris, Vickie, Annika, Bart, Kristof, Shilpa, John, Peter (standing in back), Bob, and Maciej.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we decided to spread our wings a little bit and try a longer run. We had two goals to start with. The first was to make sure the navigation really is rock solid even over long distances, and the second was to try to find another piece of lost equipment that Peter thought might be waiting to snag us. These goals would take the bot 380 meters from the melt hole, which is actually the farthest we’ve ever sent the bot away from mission control, even including all of our previous tests in the States and the DepthX missions in Zacatón. In preparation for this rite of robot passage, Vickie swapped out the 400 meter long fiber optic line we had been using up to now for a 1000 m line. While normal fiber optic would sink and droop down to the halocline in Lake Bonney, this fiber optic has a special coating that allows it to float up to the ice ceiling. This way, when the bot spins in a circle or lowers the sonde, it won’t get wrapped up in the fiber.

Vickie unspools the kilometer-long fiber optic in preparation for the bot’s380-meter journey away from the melt hole today.

A destination point was entered into the bot’s navigation system and Endurance motored off while Peter, Bill, and Vickie tracked it from the surface. The target was the last known GPS location of an old ablation stake (essentially an ~8 meter long rod used to measure how much the lake ice ablates over time) that had disappeared into the ice in a previous year. Peter said there was a small chance that the stake could be sticking straight up out of the lake sediment and might serve as a fiber optic snag if we didn’t check it out first.

Vickie tracks the bot’s magnetic beacon using a loop antenna.

The GPS point we had turned out to be inaccurate by several meters but there was also a flag marking the spot on the surface so, since we were able to locate the bot from its magnetic beacon, Bill was able to report a heading and distance to Shilpa, Kristof, and Chris at mission control, and they were able to drive right to the spot, confirming that both navigation and beacon were working correctly. A wrench securely tied to some rope had been lowered down a small melt hole at the target so that, looking from the forward-looking camera, mission control would be able to confirm that they reached the spot. Reach it we did, and we proceeded to investigate the area, spinning the vehicle and using the forward-cam to look for the missing ablation stake. After some time spent hunting for the stake we decided to bring the bot home for the final test of the day: visual homing.

This image comes from the bot’s forward-looking camera. When we saw the wrench in the field of view,we knew that we had reached the flagged point on the surface successfully.

One of the interesting technological problems with working under a 3-meter ice cap is the question of how to get a 2 m x 2 m bot covered with delicate instruments back out of the melt hole you tossed it into. Coming from the DepthX project, we knew that the bot’s dead-reckoning navigation was quite good and could get us back to within a few meters of the melt hole. But short of manually driving the vehicle up the 3-meter tall melt hole, how could we get it to ascend at the right time? The answer was machine vision. We have an upward looking camera on the bot and above the center of the melt hole we have a 12 watt LED light that blinks on and off at a specific frequency. Shilpa worked with Aniket and Greg, two Stone Aerospace programmers back in Austin, to write a visual homing program that would start up when the bot approached the melt hole. It would use the camera to identify all of the light sources above it, pick out the bright light that blinked at the right frequency, lock onto that light, and then kick in the appropriate thrusters to center the vehicle under the light and follow it up to the surface. That is, if it worked.

We had tested the visual homing in our final bot tests over the summer and it appeared to work well in the wide open waters of NBL’s brobdingnagian tank. However, we had never been able to test how it would perform in a tall, narrow tube like the melt hole, where the consequences of running just a little off course meant hitting the wall. Shilpa urged us all to have faith in the program as we leaned over the railings around the melt hole, looking down and waiting for the bot. The orange edge of the bot’s syntactic became visible in the southwest quadrant of the melt hole. It started to pass under the hole, still under normal navigation. The regular pulse of the blinking light flashed off the water surface onto our faces. As the bot passed under the hole it stopped, shimmied a little to one side and then to the other, centering itself before ascending gracefully up the hole. The skin of the syntactic broke the surface of the water and the whole room cheered. Not only had the bot navigated to a target 380 meters away under a 3 meter ice cap, but it came home and, using the visual homing, popped straight up to the surface like all good robots should. We are beginning to feel like all of our hard work is paying off.

Video, recorded by the bot as it approached and ascended the melt hole:The bot moves along under the ice; the string wiggling above the camera is the fiber optic line.It reaches the edge of the melt hole, identifies the blinking light, locks onto it and ascends to a cheering crowd.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

With yesterday’s success and some navigation data for the programmers to occupy themselves with, today seemed like a good day to work on the problem with the profiler. Through some research, Bart had established that there was a thermistor in the servo driver electronics that would trigger a fault at temperatures around freezing. This seemed like a strange design because the usual concern with electronics is that they will overheat and fail, so having a maximum temperature cutoff makes sense. At our temperatures, though, the electronics will still work fine and there is no real reason to trigger a fault. There are several ways to get around this problem and all of them involved getting into the driver’s electronics. What Bart decided to do was to replace the thermistors with a fixed value resistor.

The first step of this repair was to remove the housing that contains the profiler electronics. Unfortunately, this is not easy. Of all of the housings we might need to open, the profiler electronics pod is in the physical heart of bot, buried in cables, metal frames, pulleys and so on. We had to remove the drop sonde from its cable, remove the pulley, and undo dozens of nearly-impossible-to-reach bolts. To everyone’s surprise, we had the pod out in only two hours.

Here is the pod we have to remove, right in the center of the vehicle.

Bart slowly slides the electronics pod and pulley assembly out of the vehicle.

Bill and Bart inspect the pod after we’ve detached the pulley assembly.

Pulling the pod out of the bot was only the beginning of the process. Once we had opened the pod, it took Bart several more hours to meticulously remove the electronic components that blocked his access to the servo driver electronics, where he needed to work. He decided that the easiest fix to our temperature fault problem was to spoof the firmware temperature fault control so that it would never trip off. He did this by soldering a standard value resistor in series with the thermistor that had been built into the driver by the manufacturer. A thermistor is a like a temperature sensitive resistor. At lower temperature it provides less resistance and at higher temperature it provides more resistance. Placing another resistor in series with the thermistor adds to the total resistance “felt” in that part of the circuit. Since the firmware equates higher resistance to higher temperature, it is fooled by this new high resistance to think that the temperature is higher than it really is and it doesn’t trip the fault.

Bart works late into the night opening up the pod, digging through the layers of electronics and soldering in the resistors.

It’s good in theory, and we all hope it’s going to work.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Thanks to Bart’s long night with the servo driver electronics, we were ready to test the fix this morning. We hooked the pod, with electronics still exposed, to the bot and ran some tests in air to see if everything was functioning normally. Once we saw that the profiler drum was spooling out and winding up as directed we sealed the housing back up and spent a few hours remounting it into the bot. Now it was time for the real test—putting it back in the water. We lowered the bot nervously. Every time we open an electronics housing we run the risk of scratching the pod’s sealing surface or pinching an o-ring. Either mistake will allow the pod to leak, an obvious catastrophe. We were relieved, therefore, when the leak detector board in the pod showed normal data, no leaks. Even better was the news that the profiler was working, even after it had cooled down. We weren’t getting any temperature faults. Another hurdle is out of the way.

Bart and Bill test that the profiler is spooling cable in and out properly. The open profiler electronics pod is sitting on wood blocks between them.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Back in business with our repaired profiler, today we planned our first drop sonde mission. With Bill and Vickie waiting outside to track the bot from the ice surface with the loop antennas, the crew at mission control sent the bot under the ice on its first real data collection mission. We were done with all of our preliminary check-out tests and now its time to do some science. The idea of the drop sonde missions is this: We have made up an imaginary grid over the whole lake. The lines of grid are spaced apart by 100 meters in the x direction and 100 meters in the y direction. Every spot where two grid lines cross is a point where we want to get water chemistry measurements. To get these, the bot navigates at a depth of 1 meter below the ice ceiling to a grid point in its mission plan. When it reaches the point it floats up until the four feet at the top of the bot rest against the ice, a maneuver we call ice-picking. Once the bot is ice-picked, it is stable and begins to lower the sonde. The instruments on the sonde take measurements of the water chemistry and so on as the sonde reels out. The sonde stops lowering at a distance of 1 meter from the bottom, takes a photo of the bottom and then the sonde reels back up. While the bot is ice-picked and dropping the sonde, Bill and Vickie locate the bot’s position from the surface and mark the spot with a flag. At the end of the day, Maciej uses a GPS to get a coordinate for each flag. We can compare these coordinates showing where the vehicle has actually traveled to where the computer’s mission log says it has traveled. This is a double check for our navigation and assures Peter and John that we have an exact and accurate location for the instrument measurements we’ve taken.

Vickie prepares the flags that will be used to mark the locations of the sonde casts.

For our first data run, everything went incredibly smoothly. Bill, Peter and Vickie tracked the bot on the surface and watched as the flags marking the grid points lined up in 100 meter intervals. The folks at mission control found that things were going so well that we still had enough battery power to do an extra point on the way home. This gave us a total of eight sonde casts for the day, a very satisfying start to our scientific work at the lake.

Peter marks the location of our first data point!

On the bot’s way back to the melt hole after the sonde casts, Kristof took the opportunity to troubleshoot some problems he had been having with the USBL. The USBL is one of the bot’s navigation tools and there are two parts to it, the large transceiver is mounted to the vehicle and the 30 cm long transponder hangs down in the melt hole. It is kind of like a homing beacon: transponder sends out a signal, the transceiver picks up that signal and can then calculate the distance and bearing to the transponder. It feeds that bearing and distance to the bot and the bot uses it to help navigate home. For the past few days we had not been able to get it to work; the transceiver was not receiving the transponder’s signal, but after some experimentation today, we found the best depth at which to hang the transponder, and now that system is working.

John adjusts the depth of the USBL transponder.

Chris downloads our first lake data from the Seabird instruments at the end of the day.

Our status at the end of the first profiler mission.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Our successful sonde mission yesterday had us convinced that we were over the hump and would just be running uneventful missions from here on out. Chris, Bart and Kristof took some time in the morning to change the lens and adjust the focus on the sonde camera, so that our images of the lake floor would be crisp.

Bart and Chris work on focusing the camera on the sonde.

Once they were done, we sent the bot out on its mission for today, nine sonde drops. At the first grid point, we began to lower the sonde but less than halfway down the drop the data coming from the altimeter turned to garbage. The altimeter sits near the bottom of the sonde and tells us how far the sonde is from the bottom as it is slowly lowered. For environmental and hardware reasons, we want to avoid letting the sonde bump into the lake bottom. Normally the sonde is lowered until the altimeter indicates that it is 1 meter above the bottom. Without good data from the altimeter it is difficult to know when to stop the sonde drop and there is really no way to continue the science mission from that point, so we aborted the mission and called the bot home. Strangely, the altimeter resumed normal operation somewhere on the trip home.

Back in the bot house we started to work on the problem. We pulled the bot out of the water and, thinking that the garbage data might have been caused by a poor communications connection somewhere between the altimeter and mission control, we started to check the altimeter’s connections in the electronics housing in the sonde. Everything seemed fine, and anyhow, the altimeter now seemed to be working. We spent some time dropping the sonde in and out of the water and correlating the altimeter readings to the encoder on the spooler. Coupled with a depth-under-keel measurement from the sonar units, this gives us an additional way to know how far the sonde has been spooled out and how much distance is left as it approaches the bottom. Assuming that we don’t see anymore problems from the altimeter, tomorrow we’ll be back to running missions.

A Quickbird satellite image taken recently shows our camp and Bot House on West Lobe Lake Bonney.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

We were back to work as usual this morning. We planned a mission in the southwest end of the lake, around the same area we navigated to on our first long run. Launch went smoothly; we are really getting the hang of our routine here now. Bill and Vickie tracked the bot on the surface and the folks in mission control watched as the bot navigated from point to point. A little over halfway through the mission, though, mission control radioed a message to the tracking team, “We seem to have the fiber snagged on something. We’re going to stop here and dive a little, see if we can get the fiber free.”

In order to get as many points covered as possible per mission, the missions are planned to be long narrow loops, usually working up one row of grid points and down the next row. Somewhere in this loop, we had wrapped the fiber around something sticking out of the ice ceiling. Now, even though the bot was heading closer to home, the fiber in the bot house was still spooling out, instead of going slack to be pulled back in.

After the dive, mission control let the bot continue its planned route and hit one or two more grid points. When the fiber continued to feed out, even as the bot approached closer and closer to home, we decided to cut a few points off of the end of the mission and head straight home. Since we have a 1000 m long string of fiber, we had enough line to bring the bot home, even with the fiber wrapped on some mystery obstacle several hundreds of meters away.

With the bot safely home and the fiber optic still wrapped around something out in the lake, the debate began about how to proceed. Some people wanted to recharge the bot’s batteries and go back down and, using the upward and horizontal cameras, follow the fiber back to find whatever it was caught on. Others wanted to detach the fiber from the bot and just pull it through by hand. By pulling on both ends of the line—the outgoing and the incoming—we could feel that the line was wrapped around something smooth because there was not much resistance to tugging in either direction. In the end we decided that while finding and identifying the snag object would be useful for future missions, it was too risky to take the bot back out to investigate while the line was tangled—it might just make the problem worse. Instead, we decided to pull it through. We taped a small piece of foam to the metal connector on the end of the fiber so that it, like the rest of the fiber, would float on the ice ceiling. We tossed the connector into the water and began to pull on the other end of the line. Everyone watched with anticipation as Bill pulled the line and fed it onto the deck as it came up. We all wondered if the connector would get stuck in the snag point, should we have cut the connector off? After a few minutes of pulling line in, Bill reported that there was suddenly much less resistance in the line, the connector must have made it around the snag. It was several minutes more before the end of the line made it back to the bot house. What a relief to get out of that mess. Although we still don’t know what we got caught on—an old experiment or an imperfection in the ice surface—we had the foresight to mark the cable before pulling it through, so now we know how far away the snag was, and in what approximate direction. Even though we had to cut the mission short, we still got seven data points today.

Our status at the end of Mission 2.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we had a couple of changes in crew. We got a new helper, Leah, from the Berg Field Center in McMurdo to keep us sane, and Peter and Bart left in the afternoon for McMurdo. Since Bart had been the only person designing mission plans for the bot each day, he took some time in the morning to show Bill and Vickie how to design a mission plan and then check whether the mission length and number of sonde drop points planned was within the bounds of our battery power. After the coordinates for the mission plan were extracted from the planning map and Shilpa programmed them into the bot, we were ready to get in the water.

Our smiling assistant Leah from the BFC has come to help us stay sane. Good luck!

Shilpa and Vickie plan the upcoming mission. Mission planning is the balancing act of connecting the dots to hit as many points as possible without running out of battery power.

Today’s sonde mission took us to the southwest edge of the lake. We were able to get the bot much closer to the shore than we had predicted. We hit 9 points today, including the points we had to skip from yesterday’s truncated mission. We continue to rack up data.

Our status at the end of Mission 3.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Now that we’ve completed three successful sonde missions, we took today off. We have been working 12 to 14 hours per day out here and now that things are going well, it is time to rest. We stayed up late last night watching a Bruce Lee flick, so most folks slept in a bit and then we all went to Lake Bonney Camp to lounge about in the Jamesway. Leah baked cookies, since there is an oven at the camp, and we each had the chance to take a shower of sorts by using a solar shower bag filled with water we heated on the stove.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

This morning was deceptively warm and sunny. As soon as we got out to the bot house and started mission four, the wind kicked up and the temperature dropped. Both the team at mission control and the team out tracking the bot had a chilly day. We had a few nervous moments where the communications link between mission control and the bot dropped out due to a kink in the fiber as it spooled out of the bot house but otherwise it was a textbook mission. In terms of the number of points hit, mission four was our most productive so far, with 13 new data points. We ran parallel to the north shore of the lake and got some exciting photos of the lake bottom.

Today the sonde camera recorded this image, among others, of microbial growths on rocks at a depth of 10 meters.

We pulled the bot back into the Bot House at the end of the mission and put it on charge. Originally our plan today had been to run two missions but the tracking team was chilled and tired and we decided that the day would just run too long by the time we had recharged the batteries, so we headed off to dinner.

Our status at the end of Mission 4.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today’s profiler mission, Mission 5, took us towards the lake shore south of the Bot House. Our aim was to fill in the gap between where we had gone on Mission 3 and our keep-out zone. The keep-out zone is the area around John’s limnology tent, where we know there are active experiments hanging down into the water. To avoid entangling the bot or disturbing the experiments with either the bot or the fiber, we’ve had to designate a wedge of the lake as a keep-out. Unfortunately this wedge means that there are a few grid points that we won’t be able to get to, even though they are within our range.

We ran through our launch checklist and dropped the bot in the water. The weather was much nicer today and the mission went quickly and cleanly. There was some worry that, even with our conservative stand-off distance from the limno tent keep-out area, we might snag something under the ice on our way back to the Bot House, but Leah reported that the fiber was feeding back in as it should and the bot came home without incident.

Going through the launch checklist, Bill inspects the o-rings before sealing up the radio beacon battery compartment.

Later that day, Maciej returned to the Bot House carrying a long pipe. He had spent the afternoon working around the limno tent and had encountered one of the experiments that defined a part of our keep-out zone, an ablation stake. It had ablated out of its spot in the ice and was lying on the surface, so he removed it. While there are still experiments to avoid in the keep-out zone, it is nice to know that there is one less object in the lake to trip us up.

Maciej returns to the Bot House with one of the obstacles we have been avoiding near the limno hut, an ablation stake that has ablated out of the ice. It may be an object like this that snagged us a few days ago.

Our status at the end of Mission 5.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Now that we have our act together on these profiler missions, it is time to do the riskier missions. In our previous missions we have picked off almost all of the nearby, easy grid points and now we have to go further out. The mission plan for today was a 1620-meter long loop, with 11 grid points. It’s the farthest distance we’ve planned to traverse, by over 100 meters. According to Bart’s mission planning worksheet, it cuts into our reserve battery power. We decided that if we are very efficient with our launch procedure, we should have enough battery power to run the mission safely. The second concern is the sheer straight-line distance from the Bot House to the furthest point on the plan, 704 meters. If the fiber gets caught that far out, we don’t have enough fiber to drive it all the way back still connected. Everything needed to go right today.

We got off to a good start, getting the bot into the water quickly. The buoyancy, which mysteriously changes a little bit from day to day, was adjusted and looked good. Just before diving the bot down to the bottom of the melt hole, we noticed a small white object in the vertical thruster mesh. Since we didn’t want this foreign object to interfere with the thruster, Maciej got into a harness and leaned out over the bot to pick the object out of the mesh – it was a small chunk of syntactic that must have broken off. We took the bot down under the ice, went through the rest of our launch checklist and the bot started off to the first point for the day. When it got there, the ice-picking maneuver, where the thrusters turn off and the bot floats up to rest against the ice ceiling, didn’t work. With the thrusters off the bot was slowly sinking instead of rising. Somehow, the buoyancy was off. Given our tight battery budget for the mission we could not afford to keep the thrusters on to hold the bot against the ceiling, nor could we dally, find some other solution and then continue on the mission. The only choice was to go straight back home, take some lead off the bot and then recharge the batteries to full capacity and start the mission over.

Just before launch, Maciej leans out over the bot to remove a small chunk of syntactic that has broken off and become stuck in the mesh above one of the vertical thrusters.

The bot’s buoyancy in Lake Bonney has consistently been a bit of a pain. One would think that if we could get the buoyancy just right one day then, with no changes to the ballast or the bot, the buoyancy should be the same the next day, but that has not been the case. There are probably several factors in play here: the bot’s temperature when it goes into the water, the water temperature and density in different parts of the lake, microbubbles and so on. For this reason, we’ve been in the habit of checking the ice-picking maneuver right at the beginning of every mission, just beyond the melt hole. Today the ice-picking worked during the launch check but wasn’t working at the grid point. We couldn’t establish a cause for this problem so we decided to just deal with the situation by removing two pounds of lead.

With the batteries back on charge after our aborted launch,Bill works on adjusting the bot’s buoyancy for round two of today’s mission.

After we had charged the batteries for a few hours we were back to full charge and ready for Take Two of our mission. This time we were able to launch the vehicle in even less time and in a flash we were cruising back out to the first grid point on our mission plan.

This time the bot ice-picked normally, we did the sonde drop and were off to the next point. By this time in our field season here, all of our repetitive tasks have become second nature. Chris, Shilpa and Kristof are able to do sonde drops more efficiently now and Bill and Vickie have no trouble keeping up while tracking the bot and flagging the sonde drop points.

Bill tracks the bot’s radio beacon with a loop antenna while pulling a sledwith the flags and kovacs drill needed to mark the sonde drop points.

Bill drills a hole in the ice for the bamboo pole that will flag this sonde drop point.

On the return leg of the loop there was a moment of concern when the fiber appeared to be caught, but a short dive with the bot cleared up this problem. When the bot returned to the Bot House, we still had several amp-hours of battery life left, more than we expected. What’s more, today the bot went as far away from the melt hole as it will go in Lake Bonney and it returned home successfully.

Our status at the end of Mission 6. The grid is almost done.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

While yesterday’s mission was pretty long and took us far from home, the plan for Mission 7 was even more aggressive today—1730 meters long, and again about 700 meters straight-line distance from the Bot House. Also we would be operating close to shore again. The north shore of the lake is a steep talus slope that tops out in a large cliff face about 600 meters vertical distance above the lake. This slope is littered with huge boulders and it seemed quite likely that the slope under the ice would have some big rocks, too—hazards for the bot. So, just like the start of every mission, we had some reasons to be a little nervous.

Vickie poses next to Potato Rock on the north shore of West Lobe Lake Bonney.It is rocks like this that had us worried about bringing the bot close to shore in this area of the lake.

We topped the batteries off, dropped the bot in the water and started off. Vickie and Bill tracked the bot as it traveled between sonde points. The phono plug on one of the beacon receiver headsets broke about halfway through the mission and since time is of the essence with these longer missions, Kristof hopped on the ATV and raced out to the tracking team to give them a replacement headset so that there would be no delay in locating the bot.

As the bot approached the north shore in the second half of the mission, mission control kept a close watch on the water depth and the obstacle avoidance sonars. As predicted, we encountered a large rock on the bottom that was big enough to halt our progress to shore. We did the sonde drop from the safe point we stopped at and then proceeded parallel to the shoreline, approaching more closely once we passed the rock.

The sonde camera took this image of a large rock near the north shore. It was about two meters tall.We avoided this obstacle and happily didn’t find any others.

In no time the bot had run through the remaining sonde points without further incident. On the 350-meter journey back to the Bot House, we ran the bot on a course parallel to and 30 meters offset from the path it took out in the morning. This provides us with a patch test for the multibeam sonar, basically calibration data we can use when we post-process the sonar data.

The bot made it home safe and sound. With the exception of a couple of sonde points we might grab later when we are running missions to the glacier face, we are done with all of our 2008 sonde point targets; we have succeeded with a large part of our job here this year and our spirits are high today. Tomorrow we start on another objective: mapping the glacier face.

Our status at the end of Mission 7. We have hit all of our sonde targets for this year!

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we shifted gears from running sonde drops at grid points to mapping the face of the Taylor Glacier. The glacier ends at the head of West Lobe Bonney and the face of it extends down below the surface of the lake. Peter is interested in getting a 3D sonar map and, if possible, photos of the underwater glacier face.

We spent the morning re-arranging some of the sensors on the vehicle. During the profiler missions we had our multibeam “DeltaT” sonar facing downwards to map the lake floor as we went from point to point. For the glacier missions, we want the DeltaT to face the vertical glacier wall, so we mounted it sideways on the front of the vehicle. We also moved the horizontal camera and HID lights to face the same direction as the DeltaT, also on the front of the bot; previously they faced out from the aft direction of the vehicle to help us avoid obstacles as we drove the sonde from point to point.

The HID lights, forward camera, and DeltaT sonar were all placed on the front of the vehiclefor the glacier-mapping missions.

We were worried that we would snag the fiber close to the glacier because the lake ice is somewhat broken up there and there are large icebergs sticking up out of the lake ice. Trying to avoid this, we drafted a mission plan where we would drive up to the glacier face, spin the vehicle slowly to get a sonar scan, and then retreat along the same line we approached on. Then we would move sideways 25 meters, approach, scan, and retreat again. The resulting mission plan looked like a dinner fork, where each tine was an approach and retreat. It was not an efficient use of battery power but we hoped it would keep the bot from looping the fiber optic line around any obstacles out there. The northernmost section of the glacier face looked the most straightforward and hazard-free, so we decided to start there.

We started to run the mission and as the bot approached the glacier, it became evident that somehow either the data on the mission plan map or in the bot’s navigation was incorrect. The coordinates that should have had the bot right against the glacier actually left the bot about 20 meters short of it. Bill and Vickie, who had been tracking the bot, hopped on the ATV to drive back to the Bot House and draft some extended coordinates. However, in the last few days, thanks to the warm weather we’ve been enjoying, the surface of the lake ice has morphed dramatically and the ATV got stuck in a water-filled ditch on the rough ice, leaving them soaked and walking back to the Bot House. Armed with an ice screw and some cargo straps, Maciej went out to retrieve the ATV as Vickie drafted new coordinates and Bill changed into dry clothes.

With the new coordinates the bot approached the glacier as originally intended and the sonar scans reported good data. Bill and Vickie continued to track the vehicle until Vickie suddenly broke through a layer of ice, getting wet to her knees, at which point they decided the ice near the glacier was too instable to follow the bot any further out.

As the weather get warmer, the lake ice gets rougher and rougher. This makes tracking a slower process.

The folks at mission control were getting enticing images from the horizontal camera so they decided to approach the face a little closer to get more footage. When they did so, the bot unexpectedly bumped into an ice ledge, which knocked out the readings from the DVL (Doppler Velocity Log). The DVL is a key sensor in the bot’s navigation system so if it loses lock momentarily the bot becomes entirely disoriented, even after it regains lock. So now, with the bot in a place where we could not track it, the bot didn’t know where it was. Luckily, Chris was able to watch the sonar feedback and camera images and manually drive the bot away from the wall. The programmers estimated how much the bot might have drifted before the DVL regained lock and sent the bot an estimated location and told it to navigate back to the last point flagged by the tracking team. As it approached this flag, Bill and Vickie tracked the bot and reported the error, a few meters, in the bot’s calculation of where the flag was. Mission control reset the location using this groundtruth data and sent the bot home.

The forward camera took this image of the ice ledge the bot bumped into near the glacier.

To make matters even more interesting, by now the batteries were getting low and the bot was still several hundred meters from the melt hole. In addition, the visibility in the water had been decreasing all day and by this point in the mission, the water was quite murky. The warmer weather has been melting the glacier ice and there is now a waterfall blasting out a tremendous amount of water from the glacier face into the lake. Also, the flow in the Santa Fe stream next to our camp has increased. This influx of water is stirring the lake up and carrying in very fine-grained sediments. The result is that the crystal clear water we saw this morning is now a milky stew. The loss of visibility means that the visual homing program, where the bot follows a blinking light up the melt hole does not work because it is not be able to see the light.

Water has started gushing out of a 3-meter wide hole in the glacier face. The waterfall is about 10 meters high.

The visibility in the water has suddenly dropped from almost unlimited to about 30 cm.

Exhausted from the stressful mission, we resorted to our recovery strategy of tugging the bot in by its tether. We navigated to within a few meters of the melt hole and then Kristof slowly and carefully pulled the fiber optic line. To everyone’s relief, we soon saw a dark shadow rising up through the murk. In a few seconds the shadow became an orange blob and then the bot was home.

Upon closer inspection we were happy to find that the bot suffered no major damage from its bump into the wall. The DVL bumped the ice shelf directly but none of the sonar transducers on it were scratched, and the HID light mounted just to the left of the DVL had been bumped and was aiming upward, but it was not even dented.

Despite the chaos today, we had a successful mission. We navigated to the glacier face for the first time, got a lot of sonar data and images, and navigated home. A few more data collection runs from the glacier face and we will have accomplished our objectives here at Lake Bonney.

This is a screenshot of the live feedback from the DeltaT sonar. It shows a profile view of the glacier face at this point. The top horizontal stretch is the ice at the lake surface; below that, the glacier wall starts as a curve on the left; the middle point is a ledge jutting out and below that the wall recedes again. Mission control found this pattern common.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we took a day off!

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Recovered and ready to try another approach to the glacier face we sent the bot to the middle section of the glacier face, just south of our run on Friday. This would take the bot into the iceberg zone so the plan was to stop the vehicle periodically and do a sonar sweep to look for the subsurface portion of the icebergs. If we could, we would drive the bot into the channel between the glacier face and the icebergs.

To our surprise, the sonar scans showed nothing under the ice in the area where icebergs stood 2 meters high on the surface. It would seem that either the warm water entering the lake near the glacier has melted the subsurface portion of the bergs or that the surface bergs were formed ice that spalled off the glacier face never broke the surface of the lake ice in the first place. In any case, we were happy that this hypothesized snag hazard didn’t exist.

The water continues to be murky so we were unable to take any visual images of the glacier but we racked up a ton of sonar data on the glacier face. With today’s data and the data from our first glacier mission combined, we have mapped half of the glacier face so far.

A screenshot of the visualizer program that shows us where the sonars are getting hits.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we continued our glacier exploration, this time doing a combination sonde drop and glacier-mapping run in the southernmost area of the glacier face. The mission plan took us first to the delta south of the glacier face where we did a few bonus sonde drops in the shallow waters there. Mission control had to do a little bit of maneuvering to avoid some underwater moraines.

From the southern delta, the bot traveled north along the glacier, scanning it with the DeltaT sonar. Things went smoothly until Leah reported that the fiber was feeding out, not in, meaning that the bot was snagged. We managed to unsnag by diving the bot down and then moving to the side to get out of the snag zone before continuing. As the bot proceeded to head home after that it snagged again and this time the diving trick didn’t work. Instead, mission control directed the bot to back up past where, calculated from the distance markings on the fiber, they estimated the snag to be. After backing up, we tried diving again and managed to free the bot. Even with the extra time and battery power this delay consumed, the bot returned home after the six and a half hour mission. Now we have some great 3D data from the southern edge of the glacier face. Our job over the next few days will be to continue scanning the north end of the face.

This panorama shows the complex surface of the Taylor Glacier face on the surface. In a few days we’ll learn what it looks like underwater, too.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

In this morning’s group meeting we discussed the possibilities for today’s mission. We determined that if we gave the bot a fairly ambitious mission plan today we might be able to get the rest of our DeltaT glacier scans done by the end of the day. We decided to go for it.

Soon after starting to go through the bot’s pre-launch checklist we heard someone hail us on the helo communications channel of our radio, accompanied by the distant beat of a helo rotor coming up the valley. We had been informed that there might be visitors today, so we figured we would be giving the grand tour to some folks from McMurdo or Scott Base (New Zealand’s science station on Antarctica). The helo landed outside the bot tent and the visitors came in. To our surprise, however, these were not the normal kind of visitors we had seen before. These folks were decked out in red and green, jingle bells, and Santa hats. After marching into the Bot House and singing us a Christmas carol or two they presented us with gifts. The boxes contained the best thing you could bring to a bunch of researchers working on a frozen lake for over a month: food. There were fresh baked cookies, bread, and candies and, one of the most valuable and rare things in you can wish for here in Antarctica, fresh fruit.

Santa’s jolly elves gather around the moon pool to sing us a carol.

Our jolly visitors departed, off to spread cheer to the other field camps, and we munched some cookies and got back to work. We completed the checklist and sent the bot on its way. There were no snags today and the bot succeeded in doing a continuous sonar sweep of the remaining glacier face. Chris took the bot’s trip home as a chance to experiment with running the vehicle at higher speeds to find the most power-efficient speed. We took the bot up to a whopping .25 meters per second!

This image is a panorama south to north across the 1 km wide glacier face.
We got more than 100 million sonar hits to build the map; only about 5 million
are shown here to keep the file size reasonable. In the center portion it appears that the glacier is actually floating on the lake (there is an undercut cave at the bottom that runs about 1/3 the length of the image). You can also see moraine deposits at either end. This is a 2D end-on rendering of the glacier—the data are full 3D and we will be generating some “fly through” videos with the UIC electronic visualization lab over the next month that will give life to this and to the lake chemistry data. Click here for the largest version (8Mb).

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from Blood Falls Basecamp

Today we decided that we would use our last day of mission runs to approach the glacier face for one final time this year. While we have been able to map the glacier surface with the DeltaT over the past several days, the murky water has prevented us from taking the photographs we had hoped to mosaic and overlay onto the 3D surface map we have. Still eager to get some good images despite the poor visibility, Kristof suggested sending the bot to within a few meters of the glacier, closer than our previous stand-off distance. Maybe closer to the face we would be able to get some good images, we hoped. To minimize the risk of any bumping or snagging hazards we decided to visit a flat, uncomplicated stretch of the face that we had spotted in the sonar data from the past few missions.

Since the navigation systems lost lock the last time we approached the glacier close-up, we were cautious in our approach this time. The bot continued to function properly during the entire mission but unfortunately the poor visibility in the water thwarted our attempts to take photos, even at our closer range. The bot returned home and we pulled it out of the icy drink for the last time this year. With our last mission now completed, all that remains for us is to pack up our equipment, break down the bot house and return home to finish processing all of the data that we’ve collected. Goodbye Lake Bonney—we’ll see you again next year!

The lake’s currently cloudy water made photographing the glacier face practically impossible. Still, it is possible to make out vague shapes and variations in color in these two photos taken by the bot’s horizontal-facing camera today.

Here is the first image from above, digitally processed to show more detail.

A parting shot of our camp a Blood Falls before we start packing up.

Reporting by Vickie Siegel

Antarctica
Reporting from McMurdo Station

The Endurance 2009 mission is underway!

Chris Flesher and Vickie Siegel left the States on Friday night and arrived in New Zealand on Sunday after a twelve-hour flight (ponder that one for a second…). From there it was on to Christchurch, the city on New Zealand’s south island where the United States Antarctic Program (USAP) stages the logistics for running the McMurdo and South Pole research stations.

The next day we went to the Clothing Distribution Center and were issued ECW (Extreme Cold Weather) gear. This is all of the stuff that keeps one alive in Antarctica—things like long underwear, thick socks, snow goggles and so on. The two most important items are the voluminous parka, fondly referred to by all as “Big Red”, and the super warm “bunny boots” (more on those later). We received the requisite flu shots (disease spreads quickly in Antarctica’s close indoor quarters) and sorted luggage for the flight to the ice the following day.

This poster shows some of the cold weather gear that researchers and support workers get from the Clothing Distribution Center

On this CDC visit we were reunited with Maciej Obryk, good friend and Endurance teammate from University of Illinois at Chicago. Boisterous greeting and catching up followed and Maciej introduced 3 new folks we would be working with at Lake Bonney this year: Jim Olech, who will be assisting Maciej with his Long Term Ecological Research (LTER) at the lakes this year; Loralee Ryan, who, after a brief stint of helping the Endurance team, will be working on John Priscu’s Limno team; and Emma Steger, who will be the East Lake Bonney camp manager this year.

After a group dinner we were off to bed, excited to be heading back to the Ice the next day. We all awoke around 4:30 am to a chilly, dark morning and hopped on the shuttle back to the CDC, where the C-17 military jet leaves for McMurdo. We groggily finished sorting our luggage for the flight, weighed ourselves and our baggage for the flight manifest, sat through some briefings, ate breakfast and generally milled around before the flight. Despite the early hour, there was a festive air in the crowd of 130 support personnel and scientists heading down to the Ice. Chris likened the scene to a really big family reunion, one where you don’t know everyone but you recognize many faces, do a lot of gabbing and catching up, and find that everyone is generally ready to enjoy the times ahead.

Emma and Loralee break in their Big Red parkas while waiting in line for flight check-in.

As of this writing, we are about halfway through the 5 hour flight. About a third of the group is snoozing. Others are reading, rocking out to their mp3 players, or pursuing half-shouted conversations over the engine roar. More briefings await us this afternoon and there are trainings to attend tomorrow. That done, we will be reunited with the Endurance robot, which has been safely stored away in McMurdo over the Antarctic winter, and work will begin!

Jim, Emma, and Chris employ different strategies to pass the time on the 5 hour flight.

The C17 has landed; we are on the Ice.

Reporting by Vickie Siegel

Antarctica
Reporting from McMurdo Station

The last few days have been busy. The first wave of Team Endurance has been dealing with the practical aspects of living and working on the Ice. Nearly every facility we use around McMurdo station and in the field requires an orientation briefing. In addition to these, we’ve attended refresher courses in cold weather survival, ATV and generator operation, communication equipment and protocols, and so on. In between briefings, we’ve been getting our in-town lab space set up for the robot.

To avoid costly shipping charges, at the end of our field season last year we stored the bot in McMurdo, instead of sending it back to the states. So here, a giant grey orb amidst a yellow sea of snowmobiles, Endurance has waited all winter in the station’s Mechanical Equipment Center building. Now we have moved the bot to a building that is called—for reasons unknown to any of us—The Incinerator. The Incinerator is to be our lab/work space for the next week as we prepare the bot and our new batteries for the field. We’ve moved the bot into the building and a crew of janitorial staff came out to give the space something of a deep cleaning, since the last thing we want is to get grit into any of the electronics or into the water-tight seals on the vehicle.

The bot now resides in The Incinerator building. We like to think that the robot adds some class to the joint.

Since the bot has been sitting completely inactive since early January, Chris’s first task was to see if the main computer would boot. There was no reason that it shouldn’t—still, conventional wisdom says that if you leave your car parked in one place for 10 months without driving it, there are a number of reasons it may well not start when you come back. Fortunately, Chris was able to boot the robot up yesterday. Now we will connect all of the sensors that aren’t currently mounted on the vehicle to check that they, too, are functionally correctly.

Chris is able to communicate with the bot!

Reporting by Vickie Siegel

Antarctica
Reporting from McMurdo Station

Over the past week we have continued to make preparations for our field work at Lake Bonney. Maciej, Jim, and Loralee flew out to our camp on East Lake Bonney several days ago. They have been preparing camp for the rest of the team and have been melting an 8 foot diameter hole in the ice that will allow us to deploy Endurance in the lake.

Back in McMurdo, Chris, Vickie, and Emma have been joined by other members of the Stone Aerospace team: Bill Stone, Bart Hogan, Kristof Richmond, Shilpa Gulati and Rachel Price. This influx of troops has made The Incinerator a much livelier place. We are currently working to make sure that we deal with any Endurance maintenance, software, or upgrade issues here in McMurdo before the bot is shipped out to the field. A few problems have been encountered but we are steadily working through them and are still on schedule. Thus far we have plugged in all sensors and established that they are working. Chris has been working in the cPCI (the bot’s main computer), swapping out an old hard drive for a bigger one, installing an additional hard drive, and rewiring the cPCI’s connection to bot’s multibeam sonar unit, the Delta T, to allow us to view this sensor’s high-quality sonar data on our mission control monitors in real time.

While inspecting the vehicle, Rachel noticed that one of the six thrusters was leaking vegetable oil. The thrusters are pressure-filled with this biodegradable oil to keep water from leaking in, so it is important that that pressure be maintained. Upon removing the thruster we saw that it is leaking from the cable that runs from the thruster body to the motor electronics pod. We’re not sure why it suddenly began leaking but the most likely answer is that some part of the connector expands and contracts with temperature changes differently than the part it mates to. Since the bot had a nice cold, exposed ride on a trailer down to the warm, sheltered Incinerator, it recently went through some drastic heat changes, which may have caused the leak. Fortunately, we have a spare thruster that we can swap in. We also ordered some replacement oil and parts from the states for the leaky thruster and these arrived today with Shilpa, the final SAS installment to Team Endurance for this year.

Another system we have been working on is the vehicle batteries. The batteries the robot used last season are the same batteries that were used for the DepthX vehicle, are 4 years old, and have seen a lot of action. They are large, custom designed batteries using lithium ion cells and they are rechargeable. However, like any rechargeable battery, they degrade over time and eventually they will become unusable. Anticipating this degradation, Stone Aerospace used some upgrade funding from NASA to design and build two new batteries. We built these new batteries in August and shipped them down to McMurdo soon after. Chris and Bart have been busy finishing various wiring odds and ends on these batteries and soon they should be ready to test on the vehicle. The plan is that we’ll use these new, more powerful batteries for all of the Endurance missions this year and we’ll have the old batteries on standby as back-ups. While the old stacks were charged a few times over the winter by a technician here in McMurdo, they were still in pretty bad shape (very low charge and in a few cases individual cells even had negative charge) when we arrived to retrieve them, thus, we are now working to carefully and slowly bring them back up to full charge, if possible.

Chris checks out the wiring on one of the bot’s new batteries.

We also continue to get up to speed with living and working in Antarctica. All of the new arrivals have gone through their intro briefings. Since Rachel and Emma weren’t here on the Ice with us last year, they had to go through Happy Camper School, where newbies learn cold weather survival skills for 2 days and spend the night camped out in the snow. In the meantime, Vickie and Bill, accompanied by McMurdo’s dive coordination officers, each did a dive under the sea ice in McMurdo Sound. The extremely cold water (about -1.9°C or 28.6°F) means that divers here typically use drysuits, full face masks and surface-supplied air. These check-out dives, in addition to extensive training completed in the states, qualify Vickie and Bill to serve as divers for the Endurance project. As such they will be able smooth any sharp corners around the bottom edge of the ice hole to prevent damage to the bot and to swim a short distance to the bot and attach a tow rope in the event of a minor mishap.

Vickie Siegel enters the icy seawater.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The past week has been a blur. Bill Stone shipped out to East Lake Bonney main camp on Friday October 22 to guide the assembly of the Bot Garage foundation while the remaining SAS crew continued bot checkout and assembly at the incinerator building at McMurdo. Ten carpenters (“carps”) from McMurdo led by David “Mombok” Story had already flown out to West Lake Bonney the previous day and were camped in an array of small tents on the ice around the melt hole. They had also constructed two “Jamesway” huts (3 x 4 meter half-cylinder habitats made by Weather Haven) and were using those for a mess hall and work shop—environmental regulations do not allow any kind of contaminant to be released in the Dry Valleys so wood sawing has to take place indoors and be vacuumed up. About this time bad weather set in again with strong winds (katabatics) coming down off the Antarctic ice sheet, hitting 30 knots in Taylor Valley, driving wind chill down below -35F. Helo ops stopped for close to two days and the bot did not arrive until Tuesday morning. By that time the overall crew of 15 (in addition to the carps there were Maciej Obryk, Jim Olech, Emma Steger, Loralee Ryan, and Bill Stone) had worked two days to get the lab foundation set out and leveled. Then came the heavy lifting of getting all 16 segments loaded and bolted up, with around 300 connections to be made.

Condition 2 storms grounded most of the team in McMurdo for several days.

Work continues in the Incinerator. Vickie installs a new mount for the Delta T and the bot is plugged into the new batteries (on orange crate, left) for the first time.

Bill and a team of carpenters work to assemble the floor of the Bot House on Lake Bonney while the rest of the team is wrapping up work in McMurdo.

Life in Taylor valley is cold. Each morning we have to commute 20 to 30 minutes by six-wheeled ATV from ELB main camp to the melt hole (the previous year’s camp at Blood Falls is occupied this season by a small team of glaciologists). The coldest it has been, counting wind chill, was -58F. So you have to layer up and cover every square centimeter of exposed skin and wear goggles. Even with all that the ATV driver’s thumb controlling the throttle will get painfully cold unless you place a heater pad inside the thumb of the glove. The fastest route between ELB and the ENDURANCE melt hole is by following the “moat” ice — a rim of smooth ice surrounding the edges of the lake about 5 to 10 meters in width. The rest of the lake is a series of up to 1 meter high wind blown ridges and troughs that make cross-lake traffic tedious, slow, and bumpy even in a six wheeled vehicle. The moat ice is frequently a criss cross of crack patterns (not unlike the moon Europa’s surface), some of which are up to 15 cm wide and demand attention while driving.

Maciej and Jim have spent the past week running up to four “Hotsy” melt systems—complicated and noisy devices that burn “mogas” to heat glycol which runs through a spiral shaped stainless tube that hangs in the water, slowly enlarging the hole through which ENDURANCE must fit to gain access to the sub-ice lake. Each Hotsy also requires a large generator to power its electric pumps to push the hot glycol through the tubes, so at times the cacophony is the only thing you can hear near the melt hole. These two have been putting in a relentless around the clock effort since the heaters require recharging every four hours, day and night. With some luck the hole will be finished tomorrow.

Jim maintains the Hotsy devices that are melting the bot’s hole in the ice.

The morning of October 27 was clear and almost dead calm. Helo ops was back up and delivered the bot with pin point accuracy, landing it on top of the completed platform. A few hours later the remaining six SAS crew (Vickie Siegel, Bart Hogan, Kristof Richmond, Shilpa Gulati, Chris Flesher, Rachel Price) arrived on a Bell 212 at the melt hole. By this time half of the large Weather Haven hemisphere frame was up and in place. By 5pm we had the frame complete and began pulling up the multiple layers of over shell—first an inner layer, then 18 overlapped insulation layers and the final exterior weather layer. Each of these required ropes to be tossed over top of the 8m high arch in order to pull the sheets over and tie them down. By then the wind was picking up again and just managed to get everything tied down before gusts were back in the 15 to 20 knot range coming up the valley.

Our new batteries arrive at West Lake Bonney as an internal helo load.

The next two days (October 28 and 29) were spent finishing off the interior of the bot house (getting heating up and running, getting the electric power installed—a 10 kW diesel generator this year) and beginning the unpacking of ENDURANCE gear. By the evening of October 29th most of the vehicle sensors were installed, the profiler servo motors were in place, and one of the new upgrade batteries was completed and loaded into its waterproof housing.

Scheduled for tomorrow: initial power up of the bot for a full systems and sensor integrity check and scouting the location for the sub-chemocline glacier face access melt hole.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The “morning” (we now have 24 hour light—just some hours are dimmer than others because the surrounding peaks shadow the valley) brought the clearest blue skies we’ve yet had this year. It was somewhat warmer, only -14C, and the sun shone brightly as we commuted to work. We found the center of West Lake Bonney considerably more empty than yesterday—all of the carps but Mombok had helicoptered out early this morning. Maciek and Jim continued work on the melt hole—it is now an oval approximately 2.5m x 2m. It needs to reach a circle 2.5 m in diameter before we can send the bot down.

The morning was spent cleaning up the bot house and reorganizing following the arrival of a dozen tables from McMurdo along with a telcom team that installed a solar powered internet link to the Bonney Riegel repeater station. Mission Control was set up and projection screens installed for the main vehicle status, situational awareness, and science instrument displays. The last of the sensors were installed on the vehicle and the second battery was loaded. Around 6pm the vehicle was put on charge while Kristof read off a checklist of all electrical connectors for inspection. Several of us went around the vehicle and checked over a hundred connections while Vickie performed the final assembly of the science payload sonde sensor suite.

Bart gives the new batteries a final once-over before closing them up in water-tight housings.

Vickie ties up loose cables on the sonde.

Around mid-day Bill and Maciej drove 400 meters over to the edge of Taylor Glacier to determine a suitable location for an access hole for the vehicle. The idea is complex and will be described in detail later as the mission unfolds, but basically we will drive under the ice to this auxiliary hole and re-ballast the vehicle so that it is capable of exploring under the hypersaline chemocline at 14m depth. The water density shift at that point is so pronounced that the current vehicle would bob like a cork on water at that interface and only an additional 250 kg of ballast will allow it to submerge. We have a permit to take the vehicle beneath the chemocline only at this location. The plan is to then lower the vehicle into the chemocline (using a portable hoist) and release it, at which point it will map the bottom of the lake leading into the glacier. We believe that there is a possibility of a substantial cave under the glacier at the center point of the lake but only an actual exploratory mission will prove this out.

Maciej notes the location where he and Jim will start melting a second hole, about 30 meters from the Taylor Glacier.

With some luck the bot house melt hole will be large enough by tomorrow to perform the traditional “dunk” test to check out vehicle integrity.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

Halloween at Lake Bonney!

After a filling breakfast of pumpkin pancakes, compliments of Emma, we hopped on the ATVs for the morning commute to the Bot House. To give the Halloween morning a spooky feel, we made a pit stop to look at two of the many frozen, mummified seals on the east lobe of the lake (for more about these guys, see November 29 of last year’s blog).

Upon arriving at the Bot House, Chris, Kristof, Bart and Vickie worked through the pre-dive checklist for the bot in preparation for its first dunk while Bill, Jim, and Maciek went about clearing the layer of ice that had re-frozen over the melt hole. Once this inch-thick skin and the Hotsy melt fingers were removed, it became apparent that the hole was still not quite big enough. The bot has a diameter of just about 7 feet and the hole had a bulge of ice on one side that made it an oval rather than a circle.

Wearing a harness for safety, Jim breaks up the ice that has formed on the surface of the melt hole.

After chipping at the bulge for a minute or two with little success, Jim decided to restart the Hotsy fingers and put them to work melting out the bulge. After a minute or two of watching the water surface re-freeze before our eyes, even as the Hotsies were chugging away, we decided to employ some more advanced strategies. The floor Bot House sits about 1 meter above the surface of the lake ice so the melt hole is fairly exposed to the cold wind gusting up and down the valley. The wind also chills the interior of the House, particularly when we have the moon pool cover (a sturdy plywood panel on rails) open to allow access to the melt hole. What we needed was something to cut the wind so we took some 2.5 x 2.5 m pieces of heavy, coated fabric and fastened it to the perimeter of the moon pool. To anchor the bottom of the fabric, which was now flopping in the wind, Jim crawled under the floor, pulled the excess fabric away from the hole, laid it flat on the ice and covered it with chunks of ice that had been chipped out of the hole.

Bill and Bart attach the windbreak fabric to the edge of the floor’s moon pool.

Jim stacks blocks of ice on the windbreak fabric to anchor it down.

Now that the bot dunk-worthy and the hole has a little more insulation from the elements we just have to let the Hotsies do their thing and return in the morning.

Not having a lot of entertainment options for off-time (nor costumes for Halloween festivities), Chris decided to dress up the team by way of crayon drawing!

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

We continue to struggle with the melt hole. Since we are starting our work here nearly a month earlier than we did last year the ice is both colder and thicker (4 meters thick, compared to 3 meters last year), making melting much trickier. Last year the hole took 3 days to melt out. This year’s hole was started 13 days ago and while the wind shield we put up yesterday has helped significantly, so far the hole is still too small for the bot to fit all the way through. Bart and Kristof have become amateur Hotsy wranglers, coaxing the fussy machinery to work and readjusting the melt coils throughout the course of the day. Our original ice cowboys, Maciej and Jim, take the night shift. Between the four of them we have the Hotsies running 24 hours a day.

Vickie and Bill left the Bot House for a brief trip to set up a GPS base station at the nearest benchmark, located at the Blood Falls Camp, where we were based last year. The base station will remain anchored to the benchmark for the duration of our work here. The GPS system will allow us to obtain real-time, high-precision coordinates for the sonde-drop points that the bot will travel to once we start running missions.

Bill unpacks the base station for our Real Time Kinematic (RTK) GPS system.

Later in the day, the hole finally cleared out enough that we could just barely submerge the bot, without the orange syntactic blocks, to run some basic tests and check that none of the electronics housings were leaking. No leaks turned up and all systems functioned normally, with the exception of some minor problems with a data line to the sonde camera.

Vickie and Kristof watch to make sure the bot will not bump the side of the melt hole as it is lowered into the water for the first time this season.

The bot, minus syntactic blocks just barely fits in the melt hole for some initial in-water testing. Two Hotsy fingers (coils) continue to melt the ice during the tests.

As of this evening, the bottom of the hole is still too narrow, so it will be another long night out on the lake for the Hotsy cowboys. Thanks guys!

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

After some hard work by our night shift melters, the hole looked much more promising this morning. We kept the Hotsies running as we got down to work. We ran through the pre-dive checklist and hoisted the vehicle, again without syntactic, above the melt hole. This time, instead of doing a full-vehicle dunk we kept the bot hanging above the hole and ran sonde up and down to check that we had successfully troubleshot the sonde camera communications problem. We had, and the profiler was functioning well, so we turned attention back to working on the hole.

We suspended the bot above the water and ran the sonde down into the water for testing.

The lake water is typically crystal clear but it is also super-saturated with gases. The vibrating Hotsies knock some of that gas out of solution, making the water in the melt hole very fizzy like a glass of soda, as tiny bubbles of gas escape the water. While interesting, the effervescence decreases the visibility such that we cannot see the bottom of the ice hole. In order to get a better feel for how the lower reaches of the hole were progressing, we decided to send a human diver into the water. Vickie and Bill assembled the surface-supply diving equipment and suited up in their drysuits. Vickie did the dive and found a few hook-shaped knobs of ice sticking around the bottom and chopped these off with an ice axe, helped the people on the surface measure the diameter of the hole along the bottom, and strategically placed a trombone melt finger so that it would cleanly cut off a particularly large flake of ice.

Suited up for the cold water, Vickie is lowered into the melt hole. She is the first woman to dive in Lake Bonney.

Vickie inspects the lower reaches of the melt hole.

Satisfied with our new melting strategy, after Vickie’s dive we spent the remainder of our time this evening installing the bot’s syntactic blocks so that we are ready to go with the next steps first thing in the morning.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

To our delight, a large, irregularly shaped chunk of ice was floating on the surface of the melt hole this morning—the trombone melter had cut off the large flake Vickie had seen underwater yesterday. Removing this 1 meter long by half meter tall by 10 centimeter thick chunk of ice was a little tricky. We ended up screwing an ice screw into each end and lifting it out of the hole with the bot hoist.

This chunk of ice is all that remains of a large lump that was one of our problem spots around the bottom of the melt hole. We were able to saw it off with a trombone melter over night and it floated to the surface.

A close-up view of the ice chunk we sawed off, showing the elongated air bubbles that are present in most of the lake ice.

Once the rest of the morning ice crust had been broken up and hauled out of the hole, Rachel did some final adjustments with the syntactic mounts, Shilpa, Kristof, and Chris started going through the daily pre-dive procedures, and Bill and Vickie went out to get GPS coordinates of the Bot House for the programmers to use for the vehicle’s navigation. At some point in the middle of all this a helo landed and delivered our new, 2000 meter-long fiber optic cable.

A technician from McMurdo tests our new 2 kilometer long fiber optic cable. We will use this longer line for our missions to the far east end of the lake.

Our morning tasks completed, we regrouped after lunch and worked together to put the bot in the water and work on the ballast. Like last year, it was difficult to nail down how much lead we need to put on to achieve neutral buoyancy because of the microbubbles that form on the robot’s surfaces (see last year’s blog entry on microbubbles). Eventually we got it narrowed down and left the fine tuning for tomorrow.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

This morning we set straight to work on the ballast and got the bot neutrally buoyant pretty quickly. After the pre-dive check we lowered the bot into the water, ready to swim and perform some tests away from the hole. As the bot descended to the lower reaches of the hole for the first time this year it unexpectedly stopped just before it reached open water. We pulled out Maciek’s “fish cam”—a small underwater camera, camouflaged to look like a perch, with a live feed to a black and white monitor—and confirmed our fear. The bot was stuck. The hole had started to refreeze and now the last half meter was too narrow.

Rachel lowers the bot, complete with syntactic this time, into the melt hole for its first real swim this year.

Fortunately, it was only stuck in one direction, that is, it could not go down but it could still come up. So we brought the bot back to the surface, put the hotsies back in to work on the worst spots and ate lunch while debating our next move. It was decided that Bill would dive in and try to chisel the bottom edge with an ice chipper bar. After some hard work on Bill’s part, sure enough, good sized ice chunks started to float up and bob on the surface of the hole. After he made a couple circuits around the bottom edge, he came back up and we pulled him and the new ice chunks out.

The products of Bill’s underwater chipping efforts float to the surface to be scooped out.

Hopeful that Bill’s efforts widened the hole enough for the vehicle to pass, we dunked the bot again. Luck was with us and the bot made its way through the hole and down and under the ice. We proceeded to set up the visual homing beacon, a flashing light suspended over the melt hole. With the light in place, we ran some visual homing tests (for more on Endurance’s visual homing feature, see last year’s blog) and tested other basic behaviors: navigation, station-keeping and ice-picking. Everything is up and running!

Bill adjusts the visual homing light so that it points straight down the melt hole.

Shilpa inspects the placement of the visual homing light. The bot sees the blinking light with the upward looking camera at the top center and uses this light to navigate its way straight up the narrow hole.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

Today we tested the obstacle avoidance system. This year we have the high resolution Delta T sonar pointing forward for our sonde drop missions to identify objects, such as other science projects, hanging in the lake that may snag our fiber optic link to the bot. This is a change from last year, where had the Delta T facing down to map the lake bottom, so we wanted to see just what kind of objects the Delta T could resolve. Below are some of the results from our tests.

In this augmented reality visualization (part of the newly developed “situational awareness” system for ENDURANCE) the forward looking multi-beam sonar is swept under the ice cap at West Lake Bonney in the vicinity of the melt hole. We lowered three test “obstacles”—a steel ice chipper bar on a 10mm diameter rope; a 50 mm diameter pvc pipe; and a sack of lead weights on a 10mm diameter rope. At 15m radius we were easily able to detect them. The overhead red points are reflections off the underside of the ice cap. Interestingly, we also got returns from the surface of the super-saline chemocline at -14m depth (the yellow vertical lines near the bottom).

In this oblique image of the underside of the ice the bot is about 7 meters east of the melt hole—the underside edge of which can be clearly seen along with a long yellow vertical line on its west edge. This yellow stripe is the sonar return signature from a 50 mm diameter pvc tube that we lowered to a depth of 5 meters below the melt hole—so ENDURANCE is also able to detect plastic materials.

In this final test of the obstacle avoidance and detection system for ENDURANCE we maneuvered the vehicle to 50m radius and 7 meters depth. We removed all obstacles but the steel ice chipper bar (to simulate cables) and the vehicle was able to clearly detect it, along with the western side of the melt hole (the beam pattern from the vehicle was able to “illuminate” the back side of the hole and hence obtain ranges which show up as red vertical lines to the left of the image). The chipper bar shows up as the bright yellow vertical line projecting below the ice cap at the left of the image.

Reporting by Vickie Siegel

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

Prior to commencing production science missions this year we needed to conduct a navigation calibration. There were also further questions about the presence of hanging cables under the ice near the traditional LTR limnological research station located about 200 meters east of the ENDURANCE lab, so plans were made to incrementally approach that zone and perform multibeam sonar scans now that we had calibrated our obstacle avoidance system (see November 5 images).

East Lake Bonney camp is located about 20 minutes by six-wheeled ATV from the ENDURANCE site. Each day begins with a cold trip in the wind.

A software bug discovered this morning required a hardware reset in the motor controller pod. Vickie prepares to close up the housing after the fix is in place.

Bill aligns the forward-looking glacier imaging camera (one of three on the vehicle).

A rectangular navigation course—see figure—was established along a true north-south grid centered on the lab with the designations N1 through N8. As with the 2008 ENDURANCE mission the method by which we established the calibration was through the use of RTK GPS. Before that could take place, however, it was necessary to locate the bot. The procedure there was to use a low frequency magnetic beacon that was pendulum-mounted inside the vehicle. The null (vertical) axis of the field can be detected at considerable distance (we were able to achieve a positive location out to 150 meters radius this season through 3 to 5 meters of ice cap) using phase-locked loop ring antennas. This is somewhat of an art form to do in real-time but we developed a procedure using two individuals (Vickie and Bill) with two receiver sets. This year the bot moved considerably faster (nearly double) than the previous year, following further power consumption tests that refined the lowest dynamic drag velocity of the vehicle. Thus, the field tracking team had to move fast and keep a location lock, otherwise we would end up burning power while the bot waited at a sonde cast (chemistry) location.

Vickie and Bart generate today’s vehicle trajectory using the ENDURANCE mission planner.

We spent a considerable amount of time scanning the limnology site, finding one full-depth sediment trap and another cable structure, which allowed us to more precisely define the “no fly” zone for our data fiber on normal missions (special missions will sample the “no fly” zone later in the season by using a diversion pole—a smooth tube with a radius larger than the minimum data fiber bend radius).

Shilpa, Vickie, Chris, and Bart check out a replay from the ENDURANCE Situational Awareness 3D visualizer, developed for this year’s missions.

Following the obstacle location runs we returned to the “N-series” calibration test course. At each designated location the vehicle was put into “ice picking” mode where it was allowed to float up and stabilize under the ice cap. We then localized the vehicle on the surface using the magnetic beacon, drilled a hole, and placed a numbered flag so that we could return to the location. Later in the day GPS measurements were taken at these same locations and the data were reduced to UTM coordinates that could be compared with the vehicle navigation record. With these data, fine-tuning corrections were made to the onboard dead-reckoning navigation (one of four nav systems used by ENDURANCE).

The navigation calibration test course for today. The small blue circles to the right are obstacles detected by ENDURANCE. The larger blue circles are “keep out” zones to avoid contacting the vehicle data tether with these hanging obstacles.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The morning started off auspiciously enough with bright sun and no wind. We had the bot in the water by 11:30am (getting the pre-dive checklist and nav system alignment completed in under an hour) and successively drove to the navigation waypoints established yesterday. This time Bill tracked the vehicle using the magnetic beacon while Vickie took a GPS fix as the vehicle reached each waypoint along the course (we knew where the bot was going this time and were waiting for it to arrive at each point). The GPS points (the second set in two days) would be used to verify that the navigation system was working correctly (it was).

Sunshine and no wind can sometimes make life outside our remote lab seem pleasant.

Vickie gears up for GPS tracking of the vehicle at the conclusion of the navigation calibration tests. The differences between the actual locations reached yesterday and the originally targeted locations were used to create an adjustment matrix which compensated for any instrumental scaling and rotation errors.

Pressure ridge remnants near Taylor glacier pop up from the ice cap—underneath, we suspect cracks and bulges that snag a data fiber.

When we reached the conclusion of the navigation re-calibration course Emma Steger (our camp manager) met us with a “banana” sled laden with bamboo flags pre-labeled for the upcoming sonde cast mission planned for today. From there we branched southwest to re-target sonde locations achieved in 2008 (each of which was GPS-located in 2008 and these coordinates were then entered into today’s onboard mission so that both year’s data could be geo-registered to the same location). We proceeded swiftly along to points E5, E4, D4, C3, and E3. Before reaching F3 mission control reported a fiber snag somewhere in the loop—probably due to under ice cracks or bulges associated with pressure ridges near the glacier. We then began a series of lengthy evasive maneuvers ending with a return to C3, then to D4, then back to F3, successfully. By this time, having started with only 80% charge on the batteries and having maneuvered an additional 500+ meters we were beginning to run low on power and decided to return home, stopping at F4, F5, and F6 on the way. We got the sonde drop at F4 but as the vehicle was slowing down at F5 all communications went dead. All attempts to resurrect it electronically failed so we resorted to reeling it in—slowly—using the data fiber. The vehicle is designed for “ice picking”, using rounded posts for contacting the underside of the ice sheet, so it has very low friction resistance to horizontal motion. Provided we encountered no further ice cracks or bulges recovery using the data fiber is straight forward, but slow… about 5 to 10 meters per minute.

Following a non-recoverable communications link failure to the bot the team slowly retrieves it by tugging on the data fiber.

The prodigal bot returns safely.

With the vehicle back we began a post-mortem and discovered that the redundant batteries had both tripped around 20% power reserve. An analysis of the time-domain response of the voltages, however, showed the cause: we had been moving at high speed (twice that of last year) and the sudden stopping to acquire a sonde cast caused a current spike to the thrusters which depressed the battery voltage… enough that one cell in each of the large lithium stacks went below its safety threshold and the auto-disconnect kicked in. By 11pm we had diagnosed the problem and had developed a plan for resolving it. By 12:30am we were packed up and ready to head home… and into an approaching snow storm.

Chris and Bart ponder the power-time history of the mission, looking for clues.

As if the stars were completely mis-aligned this day, the Hotsy melter system—which we had to run in the melt hole each night in order to keep the hole from re-freezing—died, and another hour was spent in the cold. Post-mission discussions lasted till 3:30am. It was a long day in Antarctica.

Bart, Maciej, and John Priscu work on the dead Hotsy. Repairing equipment in the field is the nature of work in Antarctica.

And then the storm hit…

Sonde casts achieved on November 7 (green circles).

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The snow storm went on through the night and into mid-day on November 8. Helo flights were grounded and areas around McMurdo reached Condition 1.

Given the very late finish the previous day most people slept until around 1pm. We left for the lab at 2pm to begin a detailed assessment of the situation that had caused the battery system to shut down at the end of yesterday’s mission. A team meeting was held—always with everyone standing to get to the point—and tasks were assigned.

Chris (left), Bart, Shilpa, and Kristof discuss the chronology of the previous day’s mission. The team holds its meetings standing up—so everyone gets to the point of their thinking swiftly. We hold these meetings as needed, mainly in the morning to define the mission objectives and roles, but as needed for brainstorming and debugging.

Vickie and Bill headed off on an ATV with the GPS equipment to locate all of the surface fixes obtained during the tracking of the vehicle. Bill then reduced these data to calculate circular error probable (CEP) for the re-navigation to the 2008 grid points (the main purpose of this year’s mission is to duplicate last year’s data set to observe temporal change in the lake chemistry). The CEP was 1.92 meters, meaning on average the bot navigated to within that radius of the exact GPS point reached last year for the sonde grid points. Some (perhaps the majority) of this error was related to the method by which sonde points were acquired: the vehicle navigated to the grid point coordinates where it then went into “station keeping” where the thrusters maintained that position horizontally while allowing it to rise until it stabilized against the underside of the ice cap (the vehicle was always ballasted about 400 grams positively buoyant for this purpose). This condition is referred to as “ice picking”. At that point the thrusters would shut down. The vehicle is equipped with ice picking stand-off posts with rounded ends with very low friction resistance. So if there is any gradient to the underside of the ice (which is not uncommon) the bot can slide a meter or more on occasion before coming to rest. Even with this variation, the re-location navigation error was well within the five meter radius defined by the science team (Peter Doran and John Priscu) as being good enough for a match to the previous data set. So yesterday’s data set was good, both from the chemistry information acquired as well as its geo-spatial position.

Meanwhile, Bart, Chris, Shilpa, and Kristof went through a detailed review of yesterday’s onboard data log files to reconstruct the incident. The conclusion, as Bart had hypothesized yesterday, was that the batteries had automatically shut down just as the bot was stopping for a sonde point. The data logs showed clearly that the current draw on the power stacks reached 30 amps on fast stop—this depressed the single cell voltage of the lowest cell in the lithium stack and tripped the first battery safety latch. The second battery, similarly already reduced in power, was then tasked with all the remaining vehicle power load and it also then tripped—at an apparent 20% remaining power. Why there would be additional “stranded” power is a separate issue we will investigate in the coming days. In the meantime, Kristof began writing a current-limiting behavior for starting and stopping on high speed transit. Theoretically the voltage depression spiking will be reduced if we limit the thruster current draw and allow us to utilize closer to 100% of the battery. With the batteries now re-charged the system came up normally with all communications re-established and all sensors working normally. We are planning current-spiking tests following the conclusion of tomorrow’s long sonde mission.

John Priscu (left) and Bart Hogan are bundled up for the drive home after work at 10pm.

The view out our back door—the Matterhorn peak on the north side of Taylor valley,taken from main Bonney camp.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The bot was in the water at 11:30am. Around an hour later it was apparent that there was a navigation error which was being manifested as a scaling and rotation error. We subsequently drove the vehicle to stations F5, F4, and F3 which showed a straight line at about 95% scale and rotated 8 degrees counterclockwise from the accurate data from two days ago. We returned the bot to the lab and GPS-located the achieved stations targeted at F5, F4, and F3.

Kristof soon realized that the navigation correction transform obtained from the 2009 calibration had been accidentally applied to the previous 2008 corrections so we had been doubly correcting. We made the correction but decided to put the vehicle on charge for an hour to make up for the lost power before re-starting today’s mission. We were back in the water at 3:30pm.

Ultimately this was a 19 point sonde mission. We started off swiftly with F5,G5,G4, G3, H4, H5 then encounterd a data fiber snag when returning from the closest approach to the glacier—probably from the same type of pressure cracks and bulges that had plagued the previous mission. We modified the mission to go to G6 whereupon the fiber pulled free. The remaining stations—H6, G7, H7, H8, H9, H10, G10, G9, G8, F8, F7, F6—proceeded without issue.

View of the lake bottom at station H4 showing microbial mats.

View of the lake bottom at station H8 showing a strange reddish deposit—probably iron leaching out of the mud.

In Mission Control, Kristof monitors the live video feed coming from the sonde camera.

At this point we had 32% remaining battery power (about what we had originally wanted to return with… leaving about 10% safety margin to work with above the level where the mysterious power failure had occurred on the previous sonde mission. The actual usable power currently seems to be around 48 to 50 AH relative to last year’s 30 AH max. We expect that another 20% power is being “stranded” due to internal cell power imbalance and plan to investigate this further.

The vehicle was moving at an average of 0.26 m/s for most of the mission and so we were back to the bot garage by 9:40pm—about 6 hours and 40 minutes on the actual mission, including 19 sonde drops. This would have been equivalent to conducting two missions last year in the time of one. Emma Steger kindly brought dinner up at around 10:30pm so we all just kept working. After the vehicle successfully auto-returned to the melt hole we ran it on additional 50m laps centered on the melt hole until the batteries finally died again at around 20% calculated state of charge. The issue appears to be that the lowest cell in one stack is sufficient to drop the battery (safety circuitry cuts it out if even one cell goes low). We plan to disassemble the stacks and investigate when time permits.

Sonde cast progress as of November 9, 2009 (green circles).

Frontice precipice about halfway up Mount JJ Thompson at 1am on our way home. The lighting angles in Taylor Valley are consistently striking and distinctive—since we have 24 hour daylight here the only way to tell the time of day without a watch is to observe where the shadows are and what peaks are lit.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

This was a day off. Most people were up at 1:20pm, after having gone to bed around 3am after downloading all the data and cleaning up from the late mission of November 9. Most people wrote blog entries and sorted photos. Kristof and John Priscu collected “glacier berries”—small chunks of ice that had broken off Taylor glacier—and hauled them back to camp in a sled behind their ATV. This has been our main water source.

John Priscu collects fallen blocks of ice for our drinking water from Taylor glacier.

Today was also a whirlwind of helo activity here with carpenters coming in from McMurdo to work on basecamp improvements and PIs (“Put Ins”) of empty wastewater barrels and removal of full ones. Items to be “retro’d” (returned to McMurdo) had to be loaded into cargo nets for sling loading beneath a helicopter. A typical load is seven 55 gallon drums or a similar number of loaded propane tanks. A total of four flights landed here today.

Kristof brings and empty wastewater barrel to the Jamesway hut. Everything from dish and washwater to urine goes into these barrels.

Emma Steger prepares a 7 barrel sling load of wastewater to “retro” to McMurdo.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

Today was to be the first long range mission, going 300 meters further east than we had reached in 2008. In preparation for this we re-spooled a new 2 kilometer data fiber we had commissioned for 2009. This, plus mission planning and software upgrades keep everyone busy until 2:45pm when the mission got fully underway, targeted at achieving 19 sonde drops. We had sunny weather with a persistent 10 knot wind coming up the valley from McMurdo Sound.

Vickie “flakes out” the 2 kilometer data fiber spool so that it will deploy without hockling (a tendency of coiled ropes, fibers, and cables to form loops).

We had already logged the first sonde cast (F10) and were localizing the vehicle at G11 when at 4:45PM mission control called to indicate communications went down on the bot. The team at mission control tried rebooting; changing the short fiber from the main targeting computer; changing the fiber optic to Ethernet conversion boxes, but no go. They then began pulling fiber in to test if communications would come back—due to a kink straightening out—but also no go. So Bart and Kristof began pulling it back using the fiber with a slow, steady 2 kilogram force—enough to gently get it moving under the ice cap. Vickie and Bill tracked it for 50m to assure it was pulling straight back towards the bot house before packing up and returning the remaining 400 meters on foot. The vehicle was in the middle of a sonde caste when the communications had gone dead so it was unclear whether the sonde mission completed and the instrument package homed to the bot.

Bill operates an instrument for measuring the surface albedo at station F10. These data will be used to cross correlate PAR (photosynthetic active radiation) readings from the vehicle sonde sensors with surface illumination.

Vickie grabs a quick bite of lunch while waiting at station G11 for a decision from Mission Control (450 meters away towards the glacier) on the status of the vehicle.

The vehicle successfully returned to the melt hole at 7:44pm, whereupon an extensive investigation began that would last another day. It was floating neutrally in the water, an important sign that there had been no housing leaks. We made a direct fiber optic connection (bypassing the 2 kilometer spool) but still no connection. Similarly, a wireless link that was activated when the bot was out of the water also would not work. We discovered when the bot was hoisted out of the water that the sonde had not reeled back in—indicating a significant communications problem had affected all systems at once. Vickie connected a diagnostic serial communications cable directly into the Profiler housing and Chris was able to verify that the bot had significant reserve power and was responsive to direct local commands—and we thus respooled the sonde—about 26 meters had been paid out at the time of failure. Further investigations through other independent instrumentation data ports showed that the main processor stack data router was down. We were able to talk to the cameras and several other key instruments but it was the main processor stack that issued commands to operate the various parts of the vehicle. The batteries had more than 50% power remaining. An independent test of the 2 kilometer fiber showed that to be operating as expected.

At 9pm we recycled vehicle power and the wireless link came up temporarily then crashed. We then opened up the main processor housing. There were no “smoking guns” that would suggest a shock-induced failure (e.g. a loose connector from impacting the underside of the ice during ice picking). We held a team meeting to discuss and the general consensus was that oxidation on wires from internal power supply to router may be the problem—will investigate tomorrow.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The mission today was clear: find the cause of the communications system failure of yesterday. We had already tested all the elements of the external system yesterday (fiber, data converters) and the internal data hub itself proved to be functioning correctly when run off an external power supply dialed to the appropriate drive voltage. Similarly, the onboard power supplies were also working correctly. It took eight hours to methodically go down the list of likely contenders. In the end, the theory that wire terminations in a screw-type termination block had oxidized and thereby reduced the voltage getting to the communications hub had proved correct. In effect there had been a power “brown out” that was enough to drop the hub for the remainder of the mission after the initial failure at G11. There were parallel communications (via internet) going on with several members of the SAS engineering team in the U.S. and elsewhere to confer on this subject. Ultimately, we pulled the wires leading to the data hub, trimmed them, reterminated and soldered them and then re-installed into the terminal block. The system powered up normally. The general conjecture was that the bot had sat in the MEC engineering center in McMurdo station for 10 months between the last power up and that this had given time for a loose connection to oxidize enough to manifest itself as a reduced voltage coming out of the power supplies. We pre-empted at this point and re-terminated all the other wires going into this same power block.

Vickie connects a local computer interface to the Profiler housing. Using this and an external laptop computer we were able to respool the instrument sonde.

Chris checks voltages on a power supply terminal strip in the main computer processor housing.

The suspect power terminal block.

With refurbished connections, Chris successfully logs into the bot through the wireless interface.

Rachel reassembles the main computer. This is actually a stack of several processors. Overall there are 45 computer processors in ENDURANCE.

Meanwhile, Bart used the down time opportunity to play out a hunch regarding the 20% “stranded” power in the batteries. the new design, completed just in time for this season, used two stacks of batteries in series along with custom circuitry to balance the voltages. But that circuitry had to get its power somewhere and it was connected to the first half of the stack, slowly causing the voltage there to drop below the other stack. Safeguard circuitry looked for the lowest cell in the system and if it fell below a certain value (for fire safety) it disconnected the battery. What Bart discovered was a significantly larger power draw by the monitoring circuitry than was needed to run it. So a modification was made to the boards to reduce this demand by a factor of ten. Some test calculations indicated that at the new level of power draw from the monitoring circuits that the overall voltage balancing system would succeed (it was not designed for differential power draw). With the two halves of each of the power stacks (the vehicle uses two sets of two stacks) now balanced (manually) and the control circuitry installed, we anticipated a significant change in available power. Tomorrow’s mission will tell.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

The lead team of Vickie, Kristof, and Bill was up at 6:40am and off to the bot garage by 8am. They reloaded both battery stacks into their housings and into the bot, then reconnected power lines and re-installed ballast lead. By 10am the system was powered up and showing 100% power charge.

By noon the bot was over the melt hole for the sonde instrument calibration. Outside, winds began to pick up steadily from South Pole (katabatics) to 30 knots gusting to 35 knots. Wind gusts hitting the north end of the lab were violently shaking it—every time it moved it blew out the heater. The air temperature at the start of the mission was a warm 32F but dropping.

We shortly received a radio briefing that helicopters were grounded at McMurdo for at least two days, preventing arrival of chief project scientist Peter Doran. At 12:20pm we performed a sonde test drop to 18m depth to verify changes made by Chris and John to the sonde instrument parameters—all looked good on the live sonde monitor at mission control so we proceeded. By 12:30pm the bot was down at 5 meters depth and performing a test of ice picking behavior. This time, due to variations in temperature, the vehicle was proving to be too heavy so we recalled it to the melt hole and removed 500 grams of ballast.

The ambitious 3.2 kilometer sonde mission planned for November 13, including 19 sonde casts.

The wind was blowing down valley strongly for the entire mission without let up. Going eastward the tracking team was being forcefully pushed ahead; coming back was a fight. Taking tracking beacon readings were difficult — the wind was blowing the coils and the wind drone made it difficult to hear the tone.

The mission was successfully concluded at 7:15pm with an automated ascent up through the melt hole and a 25% remaining power reserve. We had completed 20 sonde drops today: G12, G13, F14, F15, F16, G16, G15, G14, H13, H12, H11, F13, F12, F11, F9, E7, D7, D6, E6, F6.

The total mission length was 3400 meters, including additional post-return navigation testing that was performed in the vicinity of the melt hole involving the USBL secondary localizer. Following the additional navigation tests the power was down to 12% and still usable, validating Bart’s hunch of several days ago regarding the battery balancing.

The team returned to camp at 9:20pm (an early night for us) and discovered to everyone’s dismay that the winds (which were still driving hard) had uprooted Shilpa’s and Chris’s tents. After dinner the entire team broke out replacement tents and helped set new sites up, these tied down to bigger rocks.

Status of all sonde casts (green = completed) as of November 13, 2009.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

We awoke to news that McMurdo was in Condition 1 (no travel). Here in the valleys it snowed during the evening at the higher peak levels but down low it was still dry.

During the routine (but extensive) pre-mission checklist we found that one of the six thrusters was showing a low level of pressure balance volume so it was taken out for maintenance and a spare swapped in.

Rachel completes the swap out of the #2 thruster for maintenance.

Prior to yesterday we had planned to incrementally (and conservatively) work our way out towards the “narrows” separating east and west Lake Bonney some 1.5 kilometers east of the lab. Using the revised mission planner and the improved battery behavior we realized we could acquire all of the remaining east end sonde casts in one mission. A year ago we had felt it would be required to have a secondary melt hole near the east end for “inflight refueling” and had re-designed the charging system on the vehicle for that purpose. Now with the improved vehicle travel efficiency and double power onboard it appeared we could run significant east end forays.

Our plan for today was to conduct sonde casts at E17, E18, E19, D21, E20, F19, F18, F17, E16, E15, E14, F14, and F6. Total mission length would be 3.2 km.

The mission began at 3:52 pm and the vehicle returned to the melt hole at 10:30pm with all sonde points acquired. Importantly, we had conducted a detailed multi-beam side-looking survey at two locations at western head of the Narrows. Multibeam was able to image all the way to shore on both sides. Depth at lake center in this area was 11m under keel, leaving enough to consider a more advanced mission in which the bot actually drove through the narrows and into East Lobe. At D21 (our furthest point today) we were just out of sonar range to image the location measured by Scott.

Marking the furthest exploratory mission for ENDURANCE, Vickie tracks the bot at 1.5 kilometers from the melt hole. Behind her is the “narrows” between west and east Lake Bonney, looking into East Lobe. Scott’s team took measurements here December 17, 1903.

Shortly after turn around (although still with more than half the sonde casts remaining to be performed) we had our only technical glitch for the day—at F19 communications dropped out for an unnerving 30 seconds. Then it suddenly came back. Shilpa analyzed the data and began searching a section of the onboard code she had been suspicious of for some time, ever since the earlier data link drop outs. With nearly 100,000 lines of software running the bot this would have been an insurmountable task during a mission, but Shilpa had spent a lot of time tracking this over the last 10 days and now found it—a “memory leak” in a routine designed to track the status of certain vehicle systems. Unchecked on a long mission, the errant process filled up memory and died. When restarted, it freed up memory and the system came back. The fix, until a more optimized re-write of that section could be performed, was to pre-empt and periodically re-boot that process—one of scores running the vehicle. Given the location of the bot at the time (1.5 kilometers from the hole) this was an impressive bit of thinking under pressure on the part of Shilpa.

At 8pm, still more than a kilometer from the lab, the grapel (1mm diameter micro hail) storm began with persistent 25 knot up-valley winds. The lab was already invisible from station F14 and we joked about having to navigate the tracking team back to the lab by following the bot home under the ice. By the time the tracking team returned there had been an accumulation of 1 inch of snow by completion of mission.

The grapel storm turned into a blizzard, obscuring the lab from 500 meters out in a white out.

Vickie gives Rachel a break from fiber tending following the 6 hour mission.

By 11pm the bot was on its sled at the lab. Power reserve was 21% when the it reached the melt hole, following a total of 7 hours 3 minutes in the water. At end of mission we found the bot very positively buoyant—adding the 8 kg dive bag we use to lower it each day would not get it underwater. Heavy micro-bubble formation had occurred all over the bot. There were also micro-bubbles all over the sonde (down-looking) camera window.

Shilpa, Bart, and Chris watch the new situational awareness visualizer at mission control as the bot “discovers” the melt hole on return from its long trip.

Status of all sonde casts (green = completed) as of November 14, 2009.

We drove home to East Lobe camp at 1am.

Reporting by Bill Stone

West Lake Bonney, Taylor Valley, Antarctica
Reporting from East Lake Bonney Basecamp

Most people did not get to bed until 3 or 4 am so it was a welcome sight to find John Priscu up at noon cheerily making crepes for everyone who walked in the door of the Jamesway at East Lake Bonney. Today was an off day. Many people caught up on their blogs… a luxury since our science days here are excessively long and most people are dog-tired by the time dinner is over. Somehow sitting down to write at 2am after 18 hours on your feet is difficult. A tent and sleeping bag seem more appealing. It was also a chance to look through data from the past several days at a less break-neck pace.

John Priscu hands out crepes in the Jamesway.

Shilpa, John, and Emma eventually went on a hike up to the ventifact field some 600 meters vertically above camp. Kristof went for a run along shore to the east. Chris built two snowmen (given the rare snow storm of yesterday). Vickie read Memoirs of a Geisha. In training, Bill did 155 pushups. Most watched an “Austin Powers” film following dinner.

Shilpa, Emma, Chris, Bart, Kristof, Vickie, and Chris’s creations “Frostie Boy” (left) and “Dr. Stone.” By the time Chris got to work most of yesterday’s snow storm had ablated.

Reporting by Bill Stone