Field notes: ENDURANCE

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

We awoke to the sound of tents fluttering madly in 25 knot + winds—katabatics coming down the valley. The temperature rose to 3C (37F). Bill prepared the mission plan this morning, an ambitious 22 sonde casts to mop up the entire southwest quadrant of the lake. While this was underway Vickie pulled the sonde flags from the November 9 and 11 missions and she and Rachel re-labeled them for today’s run.

Mission plan for November 16 called for another ambitious sonde cast run to clean up the southwest quadrant of the lake.

Meanwhile, the strong winds played havoc with our melt hole wind screens, lifting up and tossing heavy ballast ice into the hole that had been piled on the sheets. Vickie and Kristof went to work and re-anchored the ends of the flaps (seen as the yellow colored panels on the four sides of the moon pool access port in previous photos) using ice screws and some clever rigging tricks Vickie had picked up on other expeditions.

Project PI, Peter Doran, arrived on a helo flight at 11am, in time to participate in the team meeting. By 12:33pm the vehicle was underway. It returned at 6:35pm in a textbook mission, acquiring all 22 casts: D5, D8, C4, C5, C6, C7, C8, C9, B3, B4, B5, B6, B7, B8, B9, A2, A3, A4, A5, A6, A7, and F6 without incident. The latter station is included in all missions as a time varying measure of lake activity over the season. Total distance traveled underwater today was 2.7 kilometers with an in-water run time of 6 hours. We still had more than 40% power reserves at the conclusion of the mission.

Kristof preps the pH sensor on the sonde before launch.

Vickie locks in on the bot position for the 22nd sonde cast of the day.

After being with us during the tedious start-up phase for six weeks, SAS chief engineer Bart Hogan began the long return to the US and his family today, hopefully arriving in time for Thanksgiving. Given the substantial changes and improvements made to the hardware and software on ENDURANCE over the past year, Bart’s presence on the field team was of enormous benefit. Thanks Bart!

SAS engineer Bart Hogan leaves the valley after six weeks on the ice.

Sonde cast progress at the conclusion of the November 16 mission.

Reporting by Bill Stone

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

Although ENDURANCE is an autonomous underwater vehicle (AUV)—it has several independent onboard navigation systems and auto-return and docking behaviors and can be programmed for entirely “hands-off” missions; in addition it contains its own redundant power supplies and is self-sufficient for up to 10 hours on its own—we have found over time the enormous benefit of a fiber optic data link to mission control. On deep space missions NASA enjoys the benefits of seeing (in delayed real-time, due to the transit speed of light) the responses and actions of its deep space probes and can upload revised mission plans if problems are foreseen, or, more importantly, if new science is detected in the data stream so that the vehicle can take a closer look. For identical reasons, the science coming from Lake Bonney ranks #1 on the priority list of what we are here to achieve and we have found it prudent (given the investment in the vehicle) to look over the shoulder of the bot during most missions.

Underwater, however, bandwidth is limited and the only way to see real-time data—especially the torrents of geometry data coming from a vehicle like ENDURANCE—is through fiber optics. Thus we trail out a thin data filament on all missions. The new ENDURANCE “situational awareness” 3D visualizer was built around this capability and it has allowed us on many occasions already to catch new features and to immediately investigate them during the course of an ongoing mission.

This capability comes with a price in a sub-glacial environment, namely the possibility of fiber snagging. Lake Bonney has an unusual constituency: under the 3 to 4 meter thick ice cap is a 10 meter fresh water lens riding on top of a 27 meter thick, ancient, hypersaline layer. The buoyancy of that layer is sufficient to cause a vehicle like ENDURANCE (ballasted to free-fly in the fresh water lens) to bob like a cork on water. Within this restricted domain we had three choices in the design of the data fiber: to have it sink and float on the salt layer; to have it neutral and free-float in the fresh water lens; or to make it positively buoyant and float under the ice cap. The middle option was ruled out due to the possibility of it wrapping up on the vehicle. But we did come equipped to work either of the other scenarios. Fortuitously, it turns out that the underside of the ice cap at Bonney is glass smooth in almost all localities except for some notable pressure-ridges near the glacier, and so we have successfully operated using the floating fiber approach. There are, however, several permanent science monitoring experiments near the center of the lake that are used by the LTER program and these have cables that run the entire depth of the lake. They constituted enough of a fiber snag concern that during 2008 we designated the “shadow” area (see map) behind the limnological experiments to be a “no fly” zone. This year we came prepared to scan the entire lake.

The November 17 mission plan took the bot into last year’s “no fly” zone to achieve full lake sonde cast coverage. To do so we employed a fiber diverter (the small black circle adjacent to R1).

The concept was simple enough: sink a 100 mm diameter smooth wall PVC tube through the ice cap so that it projected out approximately 3 meters below the underside of the ice and strategically divert the fiber away from the known obstacles. After selecting this point in the mission planner Vickie tracked out and marked it using GPS. Peter Doran then took responsibility for placing the tube (the location can be seen in the two figures as a small black dot just northeast of the obstacles, shown as blue circles). The procedure involved using a “jiffy” drill to make the hole and then lowering the tube on a piece of parachute cord to the precise depth. By 11am we received the cryptic radio message “Diverter King to Bot Garage. Mission complete,” meaning the tube was in place.

Today was a sunny, windless day, so we took the opportunity while the pre-launch checklist was being run to collect GPS fixes for some previous sonde casts (E14, E15, E16, E17, E18, E19, E20, F10, F11, F12, F13, F14, F15, F16, F17, F18, F19, G11, G12, G13, G14, G15, G16, H11, H12, H13, D14, D21). The bot launched at 2:45pm with the initial waypoint being R1, just 30 meters north of the diverter tube. We took the opportunity to navigate over to the tube for a visual inspection (see figure) as well as to verify the sonar image of the limno cables (our adversary today) then continued on with the pre-programmed mission to the final sonde casts for the general lake set in 2009: E10, E11, E12, E13, D12p, D13, D12, D11, C10, D10, D9, E9, F6.

From waypoint R1 we navigated back to the diversion point (30 meters away) to verify the status of the tube. Since all gear coming to our site is flown by helicopter, the MEC shop sent the tube out in sections. The tube is actually suspended from its bottom by a length of parachute cord inside the tube and gravity holds the pieces together. We duct-taped the joints, however, to prevent a fiber snag.

The multi-beam scan clearly showed the presence of the limno sediment trap cables extending the full depth of the lake, just behind the diversion tube.

The mission proceeded flawlessly. Run length was 1803 meters over 5 hours and 20 minutes, with 42% power remaining when the bot rose up the melt hole—all predicted within a few percent by the mission planner, which Bart Hogan had meticulously calibrated to recorded performance data prior to his departure. Also, the new balancing procedure developed for the batteries indicated that all but 3% of the theoretical maximum power was accessible. And the diverter tube concept had worked. This gave us ideas for a mission none of us believed possible before today.

Vickie listens for the approach of the bot to station R1 during the November 16 sonde mission. On a long approach to the first point in a grid, the tracking team can estimate the location where the bot will be and drive there (using an ATV). By orienting the radiolocation coil horizontally and using a digital phase-locked loop receiver, it is possible to detect the approach or recession of the field. Two people using these in orthogonal directions can predict the arrival from almost 200 meters out.

The tracking team at station D9, the point of maximum angular incursion into the previous “no fly” zone.

As of the conclusion of the November 17th mission the entirety of West Lake Bonney was sampled, bringing to fruition the concept developed five years earlier by Peter Doran and Bill Stone—that a robot could do with repeatable precision what no dedicated field limnological team could achieve: the full 3D aqueous chemistry characterization of an entire sub-glacial lake in a single season.

Reporting by Bill Stone

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

With the success of the previous day’s foray into the “no fly” zone behind the LTER limno cables and the knowledge that with proper battery balancing we could likely hit 5 kilometers of cruise range with the new power stacks, we began hatching a plan to visit East Lake Bonney. The previous year we expected that it would be necessary to create an auxiliary melt hole a kilometer east of the bot garage where we could surface and recharge the vehicle and then maybe continue on to the end of West Lake Bonney. The new batteries made that obsolete, but it did not solve the problem that the “narrows” at Bonney Riegel made a sharp 90-degree turn. With the presence of boulders along the lake edge, the probability was high that the data fiber would be drawn into the boulders and snag the vehicle if we attempted to navigate through the narrows. The success of the diverter pole concept changed all that.

We began work on the complicated mission plan at 11am. This work was punctuated by the arrival, on short notice, of a Bell 212 load of NSF visitors who toured the lab for close to an hour then choppered off. By 2:20pm we had the plan and vehicle trajectory worked out: the anticipated mission length was 3,931 meters with 8 sonde drops through the center of the Narrows. Run time was predicted at 6.5 hours door-to-door with 5.5 hours underwater. Some time before that, Vickie had driven an ATV out to the Narrows with the RTK GPS equipment and had set out two new locations “R2” and “Pivot2″—the latter was the location for the diversion tube and the former was the targeting point for the bot some 30 meters to the northeast of the tube to ensure the fiber stayed on the north side of the tube as the bot headed southeast. At 3pm John Priscu drove out to run the Jiffy drill and install the pipe. By this time we had also upgraded the radio communications system at the lab with a 5-watt base station that could be received all the way to East Lake Bonney camp—the previous hand-held radios inside the lab had difficulty with interference from the metal arch frames of the habitat.

The bot was programmed to proceed directly to mid-stage targeting point R2, 1520 meters from the lab while mapping the south lake shore grounding line along most of that distance. It then proceeded southeast through the narrows and more than 400 meters out into East Lake Bonney. It performed 8 sonde drops along the way (the “Ninja Romeo” series).

The November 18 narrows mission would be the longest ever attempted with ENDURANCE. To ensure the bot would make it back we kept the vehicle on charge through the sonde calibration cycle. The vehicle was then lowered into the water, the sonde “homed”, and the cables freed to allow it to begin its journey.

The bot garage was abuzz with helo activity today, with several pickups and drop offs. Here an ASTAR is dropping off another load of AN8 (diesel) for the main 10 kW generator.

By 3:50pm the bot was underway to station R2 with a predicted 100 minute run time to get there. Meanwhile, Kristof began a novel dance physically miming the vehicle programming for today with Shilpa calling out the various commands to verify that the bot was going to do the correct thing inside the narrows. We had the multi-beam sonar configured in side-look mode and it had been programmed to scan the south shore of the lake from an 80 meter standoff on its way outbound (see figure for a glimpse of the data results from the 3D visualizer). However, once it got to the narrows we needed to perform a series of obstacle avoidance sweeps to ensure the way forward was passable. The least energy configuration for achieving this (and today every coulomb counted) was to perform a 180 degree yaw rotation of the vehicle at the sonde drop points and then continue forward, alternately sweeping each side of the narrows; on the return to base the bot would sweep the opposite quadrants and all of this was verified by Kristof’s miming routine. For the same reasons, prior to launching the bot today we kept the vehicle on charge while the sonde calibration was being performed and only removed the charge cables at the exact instant when the vehicle was ready to be released.

Kristof Richmond (standing in the bot garage) mimes the mission programming steps for the run through the narrows.

In addition to the sonde runs through the narrows, today was also the first lateral imaging bathymetry mission. We maintained an 80 meter standoff range from the south shoreline (which we had acquired with RTK GPS) and mounted the multi-beam sonar in its horizontal (forward-looking) position. Because the vehicle is orientation-independent, we rotated the multi-beam so that its field-of-view was perpendicular to shore and drove the vehicle “sideways” down the lake to achieve the desired scan. Yellow points in this figure are valid bottom bathymetry hits; the bottom of the red points represents the underside of the ice cap. Above that are multi-path ground bounce (fictitious) points which will later be filtered out in the post-processed data set.

At approximately 5:45pm Bill and Vickie detected the vehicle under station R2 and verified it was sweeping past the pivot point on the correct side for a safe passage. They continued tracking it for another 400 meters out into the wide open expanse of East Lake Bonney. By 8pm the vehicle was back at R2 and the diverter tube was removed, leaving roughly 1600 meters remaining to reach the lab. The vehicle arrived at the bot house on cue shortly before 10pm and post-processing of the data took place for another 2 hours. We headed for bed at 12:30am. Given the long last three days we gave people till noon to recover. With the additional maneuvering to station F6 and some short range navigation testing prior to surfacing the total actual mission length was 4250 meters.

Bill sets station NR2 in the heart of the Bonney Riegel narrows.

The sonde camera bottom image at station NR2, showing what appear to be dendritic microbial mats.

Looking out into East Lake Bonney from sonde point NR8.

The narrows looking northwest from NR8. Vickie sets the final drill hole for GPS tagging.

Today’s mission was of some historical interest. In 1903 Capt. Robert Falcon Scott’s party passed through the narrows at Bonney Riegel. In addition to taking several black and white photographs they also measured the width of the narrowest portion of the ice at that location. This was a crucial measurement that, together with the high resolution multi-beam measurements just acquired by ENDURANCE, enabled us to demonstrate that the water level in Lake Bonney had risen more than 16 meters since Scott’s team was there. We wondered what they would have thought had they known that 106 years later a robot would be hovering beneath where they had stood.

Lake Bonney water levels: 1903 vs 2009. This computer-generated plot shows a slice through the 3D sonar data acquired by ENDURANCE as it navigated through the narrows. Scott’s party, whose ice width measurement is plotted to scale here in red, almost certainly stood at this location, about halfway between NR2 and NR3. The top horizontal line represents the surface ice cap level today; the second horizontal line represents the measured underside of the ice cap today.

With the December 18th mission the entirety of West Lake Bonney sonde grid was completed, plus the additional 8 casts made through the narrows.

Reporting by Bill Stone

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

With the sonde casts completed for 2009 we turned our efforts today to the more complicated task of exploring beneath Taylor glacier. We completed a 3D map of the entire face of the glacier (and its north and south lateral moraine areas) in 2008 but in the central portion of the glacier it appeared that the glacier was floating on top of the super saline chemocline at 14 meters depth. Below that, we had no 3D imaging returns (due to acoustic bounce off the denser water). So our next objective was to go through the chemocline, neutrally ballast the vehicle at a depth that would split the difference between the beginning of the chemocline and the lake bottom (at approximately 28 meters in that location) to give us the best chance to enter any sub-glacial caverns, if they existed. The problem with this scenario is that there is a dramatic increase in buoyancy at the chemocline. Earlier measurements from the LTER project predicted a water density of 1090 kg/m^3 at 20 meters depth and 1110 kg/m^3 at 40 meters depth, thus a precise ballasting would be required to achieve neutral buoyancy at the desired depth. With a vehicle displacement of approximately 1.5 cubic meters estimates for ballasting the vehicle at 21 m depth ran as high as 160 kg of additional lead that would have to be added to the vehicle—otherwise it would bob like a cork on top of the chemocline.

We were operating under further, administrative, restrictions imposed by the environmental impact statement (a 3 cm thick document) that the project had to file in compliance with the Antarctic Treaty (the Dry Valleys are in a specially protected locality). This allowed for no powered flight below the chemocline except for limited forays permitted immediately adjacent the glacier. This presented a logistical problem: we had to fly almost half a kilometer from the lab to reach the glacier, yet the vehicle did not have sufficient vertical thrust to maintain itself within the fresh water lens if ballasted to operate neutrally below the chemocline. The approach that evolved over 2009 was as follows:

• create a second melt hole at the glacier
• have the bot surface there
• attach the ballast lead
• conduct the sub-chemocline sub-glacier mission
• return to the melt hole and remove the ballast
• return to the lab for recovery

The second and third steps required a second portable gantry at the auxiliary melt hole and a means to quickly attach and remove the lead. Bill and Vickie spent today transporting lead to the bot garage from the helo drop zone and working up a rigging system for quick attachment of the lead. The solution was low-tech: eight heavy duty contractor open-top haul bags were connected to four sets of double 11 mm PMI rope harnesses that could be looped over the four auxiliary lift eyebolts between the four syntactic flotation blocks (see figure). The ballast calibration test would take place tomorrow.

View of the vehicle with the sub-chemocline ballast carrier test rigging.

Meanwhile, Kristof, Shilpa, and Chris performed several hours of short range calibration runs with the vehicle out to 200 meter radius from the melt hole to test the sensitivity of the iUSBL navigation system. These suggested that the melt hole transponder battery was dying. We subsequently disassembled the transponder and replaced the power pack.

The team returned to basecamp at 8pm. At that time John Priscu announced that the sonde data were indicating a potentially exciting discovery of an anomalous, very cold water entry near Blood Falls at cast G3. He and Peter Doran had discussed the findings and requested that we develop a mission plan for a refined sonde cast matrix in that area to localize the source. Everyone was in bed at 12:20am.

Reporting by Bill Stone

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

This was planned as an extremely long day. The team was up and working early and by 10:30am a pulley system was installed over the melt hole and the first test load of lead had been loaded into the carrier bags located about the circumference of the vehicle. Three tests were conducted with the following resulting data acquired:

Ballast (kg)	Neutral Depth(meters)
145	27.7
118	21.4
91	16.7

The recorded sub-chemocline ballast data at the main lab melt hole showed a near linear fit. The team planned for initial ballasting to 21 meters depth to explore underneath Taylor glacier.

No thrusters were used in these experiments and, because the overhead electric hoist only had 6 meters of range, we used a manual, 2:1 rope pulley system and ascenders to maneuver the vehicle passively down into the chemocline.

Kristof and Bill man the 2:1 haul system to retrieve the bot following a neutral ballast test. The vehicle was sequentially weighted and the neutral stabilization depth in the sub-chemocline zone was recorded. These were compared with numbers Chris (at right) had predicted based on free-release accelerations (which we could record very accurately with the onboard IMU).

Meanwhile, Vickie had re-acquired the GPS location for the glacier melt hole (now labeled GMH09), since the position had moved since our original fix several weeks earlier due to abnormally warm weather over a two day period sending runoff water ponding at the original site. By this time GM09 was 1.9 m in diameter—still too small to allow for the bot to surface there—and Maciej and Peter had two Hotsy coils running 24/7.

Although the original mission for today, following the ballast tests, was to scan the central portion of the glacier where the sub-chemocline mission would be run and thence make a trial approach and docking at GMH09, interest began to change amongst the science team to conduct a refined grid sonde mission near the glacier effluent source. A total of 39 sonde casts were being discussed with a predicted 9 hour run time. It was decided to forego the glacier scanning and docking experiment to get these sonde data. It was going to be a marathon mission, after which the team would sleep in late, take Sunday off and then return to the sub-chemocline mission on Monday.

The ballasted bot: with 145 kilograms of lead distributed evenly in eight satchels around the perimeter.

By 2:44pm the vehicle charging had been completed and the mission plan was generated and loaded for the “Fine Grid” mission. However, at 4:30pm, not long after the bot had been released for descent through the melt hole, bubbles were seen coming out of the vehicle. The vehicle was immediately recovered and inspected and found to be in working order—the bubbles apparently having been from a captured pocket of air that did not get released during the normal “burping” exercise that we perform before releasing the vehicle. This false alarm pushed our schedule too far and it was decided to abort the mission and start early tomorrow.

At 5pm Vickie and Bill resumed the RTK GPS survey roundup of prior sonde cast location, completing all but six. Everyone was in bed by 10pm.

Reporting by Bill Stone

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

Everyone was up at 7am. The rumor today was that helo-ops was going to make an attempt to reach Peak 1882 today to repair the internet repeater link that has been down now for 11 days and counting… it’s only after you lose your high-tech link to humanity that you begin to realize how remote the Dry Valleys are.

Jim and Maciek continue work on GMH09, the glacier melt hole. We are still at least a day away from being able to surface at this location.

By 10:13am the bot was in the water and being “burped”. This was usually accomplished with a boat pole, causing the vehicle to rock significantly in pitch and roll to encourage trapped air to come loose. Chris had implemented a text translator for the vehicle status monitor so that critical warning messages would be vocalized over the speaker system in the lab. Thus, hearing the computer-generated phrase “High Roll and Pitch” boom out over the speakers meant that you were rocking the vehicle sufficiently to purge the residual air bubbles. By 10:22am Sonde Mission 16 was underway to Taylor glacier. Shortly before noon the mission was aborted. The data feed from the sonde instrument payload was being intermittently interrupted. In normal operations the Sonde was an independent autonomous entity and it would relay data packets to the main System Executive that oversaw management of the mission. Today, the System Executive reported all systems operational but for some reason the data link to the Sonde would periodically drop out. Since the fine grid sonde mission was the objective, we could not continue with only partial data being recovered. Thus we issued an override causing the vehicle to return to the lab.

During the half hour return flight from the glacier we pondered what had happened. There was no question that whatever problem had arisen was not in the main vehicle but lay somewhere between the main power/data interface and the sonde. The key clue lay in the fact that the data drop outs appeared to be periodic. The only thing that was periodic about the Profiler system was the rotation of the drum that was spooling out the instrument package. Because the drum rotated and the data and power had to come in through a fixed cable connection we employed a device known as a “slip ring” to avoid twisting the cable. This is a rather complicated device that transfers all of the electronic connections through a series of rotating contacts, all contained within a waterproof housing. We focused our efforts there. At 2pm, with Vickie leading the investigation, we pulled the slip ring from the vehicle and found it to be flooded with highly salty water. Since we had maneuvered only in fresh water during today’s mission this could only have come from the previous day’s sub-chemocline buoyancy calibrations. As we carefully dissected the instrument we discovered something odd: a radial o-ring at one end of the sealing cover was not in its proper groove, but rather was compressed into a radial gap between two of the rotating cylinder core elements. The unit had been refurbished in mid-2008 and apparently the technician charged with the reassembly had mistaken the rotating clearance gap for the o-ring groove and installed the o-ring there. From a casual glance it would have looked correct. But when the system had gone to 27 meters depth the previous day the external hydrostatic pressure was enough to buckle a short section of the o-ring inward into the gap, thus creating a pathway for water to enter. Enough water seeped in to leave a quarter liter of the brine sloshing in the bottom of the slip ring. As the drum rotated, the contacts would periodically immerse themselves and short out, dropping the communications data for a short period of time. Fortunately, the contacts themselves had been robustly designed and had not corroded. Vickie completed the debug and rebuild by 4pm. During this time the vehicle had been placed on charge and by 5:30pm we were back in the water and headed for Taylor glacier.

Vickie debugs the flooded slip ring.

Re-assembly of the errant slip ring.

The mission proceeded almost flawlessly from that point forward, with the surface tracking team spending the next 8-1/2 hours on the ice keeping up with the bot as it maneuvered to the 39 pre-designated sample points. The live GPS fixes for the actual sample locations are shown as small dark blue dots within the red and yellow target circles. The majority of the navigational drift, where present, was due to the vehicle sliding on the ice ceiling during ice picking (when the thrusters were shut down for power conservation during a cast)—the ice cap frequently was not flat and given the very low friction of the ice picking contact hemispheres it would slide more than a meter on occasion. We were not able to reach point BF14 (see figure) due to the presence of underwater obstacles. We retargeted to a point halfway between BF13 and BF14, then moved on to BF16, then BF15, and BF15a (shown as an un-labeled blue dot under the glacier) before resuming the remaining as-planned sonde casts. During the cast at BF15 the floor sediment in the last few meters absorbed the altimeter sonar pulse and the auto stop system did not trigger. The instrument payload contacted the bottom momentarily before mission control caught it and ordered a retrieval. The sonde instrument readings appeared to be unaffected and the mission was continued to completion. The bot returned to the lab at 2am and the final crew returned to basecamp at 3am.

Mission plan for November 21 called for an ambitious 39 sonde casts. Yellow-filled red circles are the target points. Real-time GPS locations of the actual sonde casts are shown as dark blue dots.

A portion of the mission trajectory. Yellow and bright green lines show the trace of the vehicle sonars on the underside of the ice cap; deep blue lines are bottom sonar returns from the lake floor. Circular clusters of activity show locations of sonde casts. The vehicle thrusters were shut down during these times and, if the ice surface was not flat, the vehicle could either slide, rotate, or both over short distances. Surface GPS recorded the final stabilized location of the sonde cast.

Although this mission was not targeted specifically at Taylor glacier, we were within multi-beam sonar range and caught several interesting glimpses of the underwater portion of the glacier. The bright red points show the underside of the ice cap and the beginning of the top of the glacier. The ice cap thinned as it approached the glacier. The shadows between the green and yellow points highlight the unknown region beneath the glacier we hope to investigate in the next few days.

Reporting by Bill Stone

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

Most members of the team were up by 11am (having gone to sleep around 4am) and congregated in the main Jamesway structure at East Lake Bonney camp. Today was a rest day for most given the non-stop pace of the past week. Also, after a long, long dry spell the internet was suddenly up… which had the effect of reducing what would normally be animated chatter around the breakfast table to a cluster of isolated, silent individuals intently staring at 10 separate laptop screens. Maybe it was better without internet?

The impact of the internet on Antarctic scientist sociology. After 14 days without internet the team catches up on email. Clockwise from lower left: Emma, Vickie, Shilpa, Loralee, Jim, Kristof, John, Peter, Chris, and Bill.

Several people took long hikes up to the ventifact fields high above camp to the south. This is a plateau-like shelf some 500 meters vertically above the lake where wind-eroded, bizarrely shaped granite blocks sit atop a field of red and black colored volcanic clinker. There were still residual pockets of snow surrounding the ventifacts.

Vickie stands atop a striking ventifact on a wide shelf of volcanic cinder some 500 meters above East Lake Bonney. In the background the pyramidal-shaped Matterhorn peak is at left center while Peak 1882 is to the right. The internet relay station for Taylor Valley lies atop the latter and any severe weather that blows through can knock it out for weeks. The only access is via helicopter and the maintenance crews must wear harnesses and clip into fixed ropes—the south face drops precipitously for over a kilometer immediately adjacent the relay box.

While those on the marathon sonde mission of yesterday took the day off, John Priscu, the recipient of the data, spent the entire day reducing the results of the 39 casts with 9 instrument logs per cast. At 10:20pm he turned from his work with a grim look on his face and announced that all data beyond station BF15 were compromised. Well, not all—just the ones that depended on the water pump to flush the sensors. Apparently the BF15 cast had plugged the CTD water pump when it touched the silt floor and although the readings looked nominally correct during the mission it was now clear that they had not been updated due to the clogged pump. The import of this message hit us all: we would have to re-run the mission for all stations beyond and including BF15. Not a good day for Team ENDURANCE.

Reporting by Bill Stone

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

The team was up at 7:20am discussing the mission plan. John Priscu requested a synoptic fine grid measurement, meaning essentially that we would need to re-run as much of the original 39-cast grid as possible. Given that at least 14 of the previous casts were good (BF1 to BF14) we decided to invert the mission trajectory and would target BF39 as the first cast for today (see figure).

The mission plan for November 23, 2009 involved a clock-wise repeat (in reverse order) of the November 21 mission to recapture the sonde casts between BF15 and BF39.

By 10am the team reached the bot garage and began working up the mission plan and going down the pre-launch checklists. We suffered a minor setback during the morning battery top-off charging when one of the parallel high power amp systems was connected to a battery with reverse polarity. The battery promptly shut down on that system (the protective circuitry worked). It was not software re-bootable. There was an immediate conference and the consensus was that the internal battery fuse had blown. Vickie and Rachel pulled the battery housing from the vehicle and disassembled it on the workbench. A 35 amp fuse solved the problem and both batteries were back on charge by 2pm. Labels were installed on the charging cables to preclude a future error.

Rachel replaces the fuse on battery stack A.

Meanwhile an investigation of the SeaBird water pump used on the Sonde sensor suite proved that it had indeed been clogged, although it was not immediately evident from an external inspection. John, Vickie, and Chris disassembled it and found a small piece of gravel blocking the impeller. By 4pm the vehicle was down-hole and passed both the ice-picking (positive buoyancy) test and a sonde test cast at F6 that John reviewed and found to be delivering valid data. With that the vehicle began a half hour traverse to the glacier. The protocol for today was slightly different than two days ago. We skipped the surface PAR measurements (John indicated he already had what he needed from that area) and only performed GPS-tracking at the grid end points. The data from the previous mission had been reduced this morning by Bill and found to indicate a 1.7 meter CEP navigation accuracy, including the effects of sliding (up to a meter or more) that occurs during ice picking stabilization (due to the uneven, sloping underside of the ice cap). This was repeatable enough accuracy that we did not need to ground-truth all casts today, just the ends of each scan line for a spot measurement check.

John Priscu begins the investigation into the clogged water pump on the Sonde instrument package.

Vickie and Bill left the bot garage at 4:15pm to lock in the starting fine grid position for the vehicle at BF39. However, at 4:30pm, with the bot only a few tens of meters away from the radio location team, the navigation system crashed. Chris immediately confessed that he had, unbeknownst to everyone on the team until that minute, re-written the vehicle status monitor the previous evening and installed it to see how it would perform. It took close to half an hour after leaving the melt hole before a bug in the new code manifested itself and dropped the navigation system. Fortuitously, the bot was not far from fixed Sonde cast station D3, for which we had solid GPS coordinates. Thus, Bill and Vickie talked the mission control team in to the known point by providing guidance vectors to closure. When the bot was directly beneath D3 the coordinates were uploaded via the data fiber and the nav solution was back on track. Chris purged the new status monitor and re-loaded the prior version and we were back on the job.

Vickie locks in the GPS coordinates for sonde cast BF39, start of the fine grid sonde casts for today.

Things proceeded smoothly for the next five hours until 9:20pm when the cast at BF10 again lost altimeter data in a particularly non-acoustically-reflective zone of soft lake floor sediment and momentarily touched bottom before mission control could issue an over-ride (they could see it happening on the sonde down-look camera). We discussed the portent of this in view of the previous loss of data update to those sensors (3 of them) that depended on the water pump and Peter made the call to end the mission. He had been monitoring the live data from the sonde instruments along the way and was pleased with the data. They had already indicated that the anomalous phenomena of interest (a previously unknown cold water source at -20 meters) was located further south and west from any of the remaining grid points (BF9 through BF1). Combined with the previous good casts from BF1 through BF14 Peter declared the data set to be complete and we issued the recall message to the bot. It returned at 9:55pm and completed autonomous melt hole detection and docking.

While conducting the sonde casts we also programmed in yaw-rotational sweeps of Taylor glacier in preparation for the upcoming sub-glacier exploration. This plan view shows the edge of the glacier (in bright blue) along with section lines for the next two profile images. All of these were created using the multi-beam imager mounted in the forward-looking position.

A multi-beam side-look view of the north Taylor glacier moraine under the Lake Bonney ice cap.

Multi-beam sectional image of Taylor glacier beneath the Lake Bonney ice cap. Note the undulation of the lake ice thickness and the thinning as it approaches contact with the glacier (due to warm water run off from the glacier as summer begins to arrive in Antarctica). The main object of interest is the dark gap under the ledge at 16 meters depth. To see further, the bot has to be ballasted to descend below the chemocline, and will be the subject of the next few missions, now that GMH09 (the glacier melt hole) is open.

In parallel, efforts at GMH09 (the glacier melt hole) continued, with Peter, John, and Bill setting up the gantry crane over the hole and mounting the second electric winch. The hole now appears to be large enough to permit the bot to surface there.

More diesel fuel for the Hotsies arrives to complete the melting of GMH09.

The long ride back to East Lake Bonney camp continues to get longer as the moat ice begins to crack up, in some cases leaving 10 cm gaps where none existed when we first arrived. By 11:30pm the entire crew was back at camp working on dinner. It had been a day of success mixed with small glitches. Today we concluded that an investigation into the (now repeatable) Sonde altimeter spoofing under certain sediment conditions on the lake bottom needed a better-automated solution. With the sonde casts now complete and upcoming sub-glacier exploration and lake bathymetry pending, however, this became a side project that we vowed to return to before departure.

Reporting by Bill Stone

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

The team was up at 9am. A little over a centimeter of dusty snow had accumulated over the night and it was dark and overcast, unusual for the Valley. The surrounding peaks were obscured in snow and clouds. The internet link was down. Helo ops were cancelled today. Neither supplies nor personnel would be making their way towards Lake Bonney.

The afternoon view of the bot garage and the southern flank of Mt. J.J. Thompson from GMH09.

The plan for today was to run a horizontal sweep of auxiliary sonde drops at 25 m spacing along the glacier face from north to south at about 10 m standoff from the ice wall in order to obtain a more exact locality for the mystery source of cold water that had been detected in the fine grid. The grid casts of the last three days had indicated that a pronounced cold source was coming in at around 21 meters depth from somewhere south of the BF35 to BF39 line. The presumed source was from the glacier grounding line. Our job today was to find the low point in temperature along that line.

By 10am Peter and Emma were off to GMH09 to start the Hotsies in a final effort to assure the glacier melt hole would be ready for use later in the day. The main crew reached the bot garage at 11:10am and began work on the mission plan. By 4pm the Bot was in the water and the glacier melt hole team reported the site was ready for arrival.

Mission Plan for November 24, 2009. The outbound trajectory goes through waypoint E3 as a tracking check then to the glacier face proximity points BF13, BF15, BF24… BF45. Because the anticipated stand-off distance was less than 10 meters from the glacier we constructed a fall-back trajectory (BF24a … BF45a) in case an unforeseen obstacle appeared. The vehicle periodically swept the forward and westerly (left) pathway with multi-beam to guard against any surprises. The vehicle never had to deviate from the red path, ultimately converging at GMH09 for the first underwater traverse and surfacing at West Lake Bonney.

The mission proceeded smoothly until around 6:39pm, outbound about midway between BF15 and BF45, there was an apparent fiber snag. This was rough terrain under the ice in this location, as we had learned last year. Shilpa momentarily over-rode the mission sequence and caused the bot to dive a few meters (still above the chemocline). This evasive maneuver was enough to free the fiber and we resumed the mission at 6:50pm. At 7:30pm an auxiliary sonde drop mid-way between B3 and BF45a produced the lowest recorded water temperature reading in West Lake Bonney:—5 C (23F) [at UTM N: 1370881.271; E: 435585.644 meters]. The navigation system was performing well. Real-time GPS acquired by Vickie and Bill had shown a horizontal error (including ice picking) of less than 1 meter at E3 on the inbound journey and 0.8 meters at B3 just before the low temperature measurement.

Peter Doran and Vickie Siegel anxiously await the arrival of the bot at GMH09, just 30 meters from the glacier face. The 2×4 across the melt hole supports the collimated alignment beacon. Shimmering on the water surface is from thruster centering action of the bot as it rises up through the 4 meter thick ice cap.

At 8:30pm ENDURANCE completed the first “through-trip” in West Lake Bonney and surfaced at the glacier melt hole, GMH09. By 10pm the bot had completed autonomous recovery back at the lab and the entire crew was enjoying dinner before 11pm, an early night. With the successful completion of the localization and auto-docking and with the melt hole completed we were now ready for the sub-chemocline exploration of Taylor glacier.

Peter Doran waves hello to the crew back in mission control (the upward looking machine vision camera has a wide field of view and can easily see both Peter and Vickie).

Chemistry profiles from the Sonde instrument package in the refined cast zone near the glacier. These indicate an anomalous cold water source originating somewhere along the glacier line at a depth of 21 meters. Later work would locate an even colder source at -5C near BF45a.

The bot scans the upper face of underwater Taylor glacier at its interface with West Lake Bonney. The lowest green returns to the right show the lip of the glacial under-hang at the chemocline. The next two missions will explore underneath this ledge.

Reporting by Bill Stone

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

We were up early at 6:20am catching up on data processing and planning for today’s mission under Taylor glacier. The internet remains down and the tops of the surrounding peaks are still obscured in fog and snow. The mission plan (see figure) was conservative, given the absolutely unknown nature of what lies below the chemocline and underneath the glacier. The bets amongst the team as to what the bot would discover ranged far and wide from “a continuation of the vertical glacial interface wall straight to the bottom of the lake” to “a vast sub-glacial tunnel” extending westward under Taylor glacier.

Mission plan called for the bot to surface at GMH09, load up on ballast, then maneuver to pre-points BF15 through BF35 and from there to make tentative perpendicular excursions under the glacier to the west, leaving a straight egress path to the melt hole. The multi-beam data from Sections A-A’ and B-B’ are plotted in the subsequent figures.

The ice team awaits the arrival of ENDURANCE for re-ballasting for the first sub-chemocline mission. Taylor Glacier forms the backdrop, just 30 meters behind melt hole GMH09.

By 2pm the bot had autonomously surfaced at GMH09 and the crew, led by Vickie, went to work adding a series of ballast test loads to the vehicle to confirm the previous calibration done at the bot garage melt hole several days earlier. The first measurements suggested that there was a problem—the bot was sinking further than it did at the main melt hole. We therefore set about running another calibration run since it was certain that the bot was going to have to be ballasted to a precise depth once we got the first multi-beam data that showed where the best approach depth would be to get under the glacier. Within the chemocline we had limited vertical excursion capability. Even at full upward or downward thrust we would be limited to about a 6 meter rise or descent, all the while potentially stirring up bottom sediments. So the concept was to precisely ballast at the depth of interest and set the bot free for horizontal exploration. Here are the data we acquired today:

At Glacier Melt Hole
Ballast Load (kg)	Depth Reached(meters)
85	16.9
88	17.2
90	17.64
91	18.01
105	21.2
118	23.4

New ballasting data acquired today at GMH09 showed a striking offset from the data originally gathered at the bot garage melt hole several days earlier. The consensus is that fresh water entering from underneath the glacier is locally mixing and slightly reducing the salt content of the chemocline at this locality.

We finally ballasted at 105 kg of additional lead, which took us to a neutral depth of 21.2 meters. With all systems go the melt hole team radioed back to mission control that the bot was free and descending into the chemocline and they began a close approach to the original BF15—BF35 line (see mission plan). Because of the bot’s depth (at 21.2m) and the rising moraines to the north and south we were unable to reach BF15 without violating the ENDURANCE under-keep minimum depth. The deepest lake bottom depth recorded in this zone was 27 meters, so there was not a lot of maneuvering room. For the same reason we were unable to reach BF35. But, within that line we were able to sweep the face of Taylor glacier to the bottom with clean line of sight.

Getting down to the business of negatively ballasting the bot. The overhead 1-ton gantry is just barely strong enough to get the vehicle 2/3 out of the water—but high enough to add the additional 105 kilograms of lead to sink the vehicle to 21.2 meters depth, 7 meters below the chemocline layer.

ENDURANCE moved up close to the nose of the glacier at BF24 to try to get images of the grounding line. However, we were ballasted too heavy and the down-look cameras on the Sonde showed that we were beginning to stir up lake bottom sediment with the vertical thrusters attempting to maintain minimum standoff under-keep clearance so a retreat was ordered. We then cautiously moved southeast and again moved in close to the glacier about midway between BF25 and BF34, and midway between B34 and B35. The further southeast we went the shallower the lake floor / moraine deposit became. Based on this data it seemed clear that the ideal ballasting depth would be about 19.2 meters, and we made a note of that for tomorrow’s closer proximity explorations.

The bot’s multi-beam imager brought back a treasure trove of clean 3D map data (see Section figures A-A’ and B-B’ for a sample of some 2 meter slices of the data taken between BF25 and BF34). Unfortunately for those who had wagered on the presence of a vast sub-glacial cavern, there was no borehole leading off into the unknown. But there was plenty to be investigated further once we had the right neutral approach depth to minimize disturbance of the grounding line sediment. We auto-docked back to the melt hole around 9pm, removed the excess ballast, released the bot and it returned home for a second autonomous docking and ascent at a mission clock time of 7 hours and 26 minutes underwater. It had been a good day. We had pulled off a dangerous exploration mission and did not lose the bot. Tomorrow we will return for close-in visual imaging.

Section A-A’ (see mission plan above) shows a multi-beam 2-meter-thick slice of the underside of Taylor glacier, below the chemocline. Above 16m depth (to the right) the glacier face rises above the chemocline to the Lake Bonney ice sheet roof. Generally there is a concave cusp above this level (see the multi-beam image for November 26 that shows this well). The “grounding line” is where the glacier ice mass rests in contact with the moraine sediments. It is along this line that the anomalous cold water source localized yesterday is presumed to originate.

Section B-B’. Similar to the previous section but further south along the glacier face. ENDURANCE had a hard obstacle standoff limit of 1 meter of overhead space and 2 meters under keel for maintenance of navigation and image sensor reliability. The vehicle cross section is to scale and is located at the actual closest point of approach to the grounding line in this location.

Reporting by Bill Stone

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

Mission Objective: Investigate in greater detail the grounding line voids underneath Taylor Glacier and below the chemocline. Pending the early conclusion of the first mission, generate a second mission plan on the fly and run an autonomous shore bathymetry scan of the southwest quadrant of West Lake Bonney.

The crew was up at 7:20am and off to the lab by ATV at 9:15am. Kristof and Bill worked the 3D glacier geometry data from yesterday’s scans to select a target point for the start of today’s close-in glacier contact imaging. By 1:50pm the bot was in the water and on its way to GMH09. New ballast calculations performed by Chris and Bill using yesterday’s test data, combined with the geometry data from yesterday, indicated we would need to re-ballast to 85 kg negative at the surface to be neutral at 18 meters below the glacier lip at the chemocline. By 3pm the bot was at GMH09 and the trim weights were added and the vehicle released.

The first portion of the November 26 mission involved close-in exploration of the underside of Taylor Glacier, in an effort to locate the grounding line between the glacier and the lake sediment. The bot was re-ballasted to 85 kg negative at the surface at GMH09 and released to approach the underside of the glacier. The furthest penetration of the imaging sonar underneath the glacier occurred just south of BF35 at Section C-C’ and showed a 30 meter deep overhung recess.

At 4pm the bot discovered a cave going back under the glacier just south of BF35 for more than 30 meters (see Section C-C’ figure). It was too small to drive into, unfortunately. Similar investigations south towards BF45 indicated closure between the lake floor sediments and the underside of the glacier at less than 30 meters west of the main overhang at the chemocline, so it was apparent that no sub-glacial borehole existed. The multi-beam data from today and yesterday produced high-resolution imagery back to the grounding line across the entire central portion of the glacier (between the north and south moraines).

This is a plot of a 10 meter thick imaging slice of Taylor Glacier, looking south, taken along Section C-C’ (see the mission plot). East is to the left; west to the right. It clearly shows the grounding line beneath Taylor Glacier (which shows up mainly as blue and purple in this depth-cued plot). The lakebed and moraine sediments show up as green. The vehicle is shown to scale at the point of closest approach west of BF35. This figure also shows the presence of a concave ledge in the glacier face just above the chemocline (which starts at approximately 14 meters depth). This is typical along the central portion of the underwater glacier.

This high-resolution image of the moraine lake bottom sediment was taken by the Sonde down-look camera during an auxiliary cast of opportunity at BF35x.

This is a close-up view—taken by the forward imaging camera—of the overhang beneath the glacier at a depth of -16 meters along Section C-C’. The overhang continues for 30 meters to the west before the lake floor sediments rise to meet the ice at the grounding line.

By 5:50pm the bot was back to GMH09 and the sub-chemocline ballast was removed for the final time. Given that fiber snag problems had occurred several times this year in the vicinity of B3 we plotted an evasive trajectory back to E5 before heading to the southwest shoreline for bathymetry scanning. By 6:10pm the new mission code was uplinked to the vehicle while it was enroute to E5. At 6:12pm the bot went fully autonomous for the remaining 3 hours of the mission. The standoff range was 80 meters from shore. The bathymetric scan proceeded rapidly and smoothly with complete coverage to the grounding line between the West Lake Bonney ice cap and the lake floor. The coverage was high definition with 4 multi-beam scans per second (480 measurements per scan) and the vehicle running at 0.29 meters/s. At 8pm the vehicle turned the corner at BA3 (see secondary mission plan figure) and headed towards home. We were receiving much more detail of the lake bottom than anticipated considering the side-look orientation of the imaging sonar. At 8:30pm the vehicle crossed within range of the LTER limnological test site and captured a complete 3D map of the location of all of the suspended cables there (see figures). Considering that most of those cables were only 6 mm in diameter this was an impressive confirmation of the obstacle detection system. At 8:30pm the bot autonomously located the melt hole and rose to a cheering crowd. We were packed up and headed home with another load of data at 10:30pm.

Bathymetry Mission 1 was uploaded to the vehicle while it was traveling enroute to E5 from GMH09. The bot went fully autonomous at 6:12 pm and conducted a scan of the southwest shore of West Lake Bonney, returning on its own to the main lab melt hole at 8:30pm.

Results of the lateral bathymetry scan, plotted at a decimation factor of 100 (that is, only 1 point in 100 of the actual data is plotted here to show typical patterns of coverage). The system acquired good bathymetry (lake bottom topography) data all the way out to the grounding line between the lake ice sheet underside and the lake bottom. Ice thickness remained approximately 3 meters all the way to shore.

Frame capture from the situational awareness 3D visualizer shows that the bot cleanly imaged the locations for the existing permanent NSF LTER experiments (to the left of the vehicle track) located at the center of West Lake Bonney. The largest cluster is in fact a group of four 6 mm cables that suspend a series of sediment traps, used to monitor materials that may seasonally enter the lake, either through the ice cap through ablation and melting or from glacial melt coming in from the end of the lake and flowing atop the chemocline.

Reporting by Bill Stone

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

Mission Objective: Acquire lake edge bathymetry around the south side of the lake to the narrows at Bonney Riegel and then return via the entire north shore.

We were up at 8:10am to overcast skies. It was relatively warm (for Antarctica). The thermometer on the Jamesway read 7C but no one believed it since it was in direct sunlight. The wind chill on the ice felt much colder. But the sun was having an effect on the lake ice on the south side edges and our normal ATV route had become dangerous. We crossed the main bulk of East Lake Bonney directly to the north and then rode the much smoother, harder edge “moat” ice from there to the lab.

The sun had also affected the bot garage lab, ablating the edge ice and dropping the foundations on the east side of the structure. We periodically inspected this—in a single season a third of a meter of ice ablation was not unheard of here—and today found 40 mm gaps along the middle east side edge beams. Fortunately, we had known about this effect in advance and the foundation was equipped with industrial screw jacks, which we now activated to level up the lab.

Solar ablation on the east side of the bot garage foundation left a 50 mm vertical gap between the support beams and the upper structure, possibly explaining the difficulty we had been having of late with moving the loaded gantry inside the lab.

Fixing the foundation problem amounted to a few turns on the leveling jacks spaced about the outer perimeter of the lab. Here the 50 mm gap we discovered in the morning has been closed up.

By 11am the mission plan was generated, the IMU aligned, and the launch checklist well underway. This would be the most ambitious mission yet in terms of traverse length. The multi-beam sonar imaging system was again set up in side-look mode. No special physical arrangements were needed to do this. ENDURANCE is axysymmetric, so it is directionally-insensitive. So to map the side of the lake while moving forward we simply rotate the vehicle 90-degrees to the velocity vector and the onboard coordinate system transformations are automatic. At 11:55am the bot was in the water and on its way on autonomous bathymetry mission 2. At 5pm the it returned to the melt hole in one pass from the western end of West Lake Bonney without any additional search, discovered the central alignment beam and surfaced directly. The water was clear enough to see the vehicle at -5m as it returned. There were no incidents on the entire mission. There was no intervention from the team. Mission duration was 4 hours and 50 minutes with a trajectory length of 3.6 kilometers. A total of 34 million valid (non-noise / non-multipath) bathymetry measurements had been made and logged. This left only selected gaps in coverage across the lake which we felt could be covered in no more than four additional missions.

The longest mission yet for ENDURANCE was relatively simple in geometry: proceed straight to the south side of the lake and follow the perimeter around, scanning the shoreline from an 80 meter standoff radius. This resolved a long standing debate that had gone on regarding how to effectively capture the shallow portions of the lake bathymetry. In shallow water the imaging sonar, pointed in down-look mode, was inefficient because there was not much distance below the keel of the bot for the beam to fan out. So we would have had to make a very large number of concentric passes in this fashion to ensure we had measurement data over these areas. But if we inverted the problem and scanned from the side, we could cover the entire problem area in one pass. The 80 meter standoff distance was chosen because this had proven to be a maximum range for the imaging sonar before we began seeing noise in the data. The objective was both uniform as well as quality bathymetry data.

In Mission Control, Kristof (left), Shilpa, Chris, and Peter monitor, but don’t interfere with, the independent actions of the bot. The 5 hour, 3.6 kilometer mission proceeded without incident.

The crew was back at the ELB Jamesway by 6:30pm… a short day by our recent standards. Total automation can be boring sometimes.

Results from Autonomous Bathymetry Mission 2: a total of 34 million measurements along most of the lake shoreline. Internal gaps in the data will be filled in during the next four missions.

Reporting by Bill Stone

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

Mission Objective: recover, process data, go on hikes, eat lots of food.

This was our “Thanksgiving” day (the real holiday had passed several days ago while we were in the middle of key missions that we wanted to get under our belt before taking another break). Everyone slept in. The crew was up around 11am. Peter worked on his December 6 lecture back at McMurdo station. Doing similarly, Bill reduced data for the narrows and the November 26th glacier exploration to generate cross sections and movies for the lecture.

Several people went on hikes—it was a beautiful sunny day with little wind, a rarity for Taylor valley. Bill and Vickie hiked 3 kilometers past the east end of East Lake Bonney. They met Shilpa and Emma on their way back after having retrieved an ATV they had left at the east end of the lake. When they returned they found the vehicle pointed in the reverse direction from where they had left it. This was Shilpa’s practical joke. The four of them rode home together on the ATV. Meanwhile, Kristof hiked to the ventifacts, descending to the east end of the lake and then jogging back to camp.

Dinner was on at 5:30pm—way early for us—and there was lots of it: turkey, gravy, dressing (both vegetarian and meat), peas, corn, roasted veggies, kumara (New Zealand sweet potatoes), croissants, and pumpkin and cherry pies, all fresh baked by the team.

Chris supervises the carving of the Thanksgiving turkey at East Lake Bonney camp.

The team digs into a fine meal. Clockwise from left: Emma, Vickie, Chris, Rachel, Peter, Kristof, Shilpa, Bill.

Reporting by Bill Stone

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

Mission Objective: complete the final section of lake edge scanning with an autonomous, fiber-disconnected mission (we will retain the physical fiber tether but the link will be broken at the bot house). Subsequently, perform several autonomous sonde casts at F6 to test new code that has been developed since the November 21 and 23 instrument pod grounding incidents; then a calibration of the sonde encoder.

The crew was up and eating breakfast at the Jamesway by 7:30am. A full team meeting was held at 9am to plan out the final 2009 missions. Most of these focused on the completion of the lake bathymetry and a notable re-run of the Bonney Riegel narrows mission—not because of data error but in order to gain a second, temporal, data set that would show how the chemistry measurements changed at the shallow sill separating East from West Lake Bonney (WLB) as a result of the now increasing melt runoff from Taylor glacier. The team agreed to the following remaining missions:

• Nov 30: tether-disconnected (at bot house) bathymetry, northwest quadrant WLB
• Dec 1: tether-disconnected (at bot house) bathymetry, southwest 1/3 of WLB
• Dec 2: Narrows sonde re-run, with data fiber and with manually supervised sonde drops
• Dec 3: Narrows sonde re-run (if necessary), tether-disconnected (at bot house) or mop-up bathymetry southeast quadrant behind the limno cables
• Dec 4: pack up

The mission plan for November 29th, 2009 was fairly straight forward—a bathymetric side-look scanning run at 80 meters standoff range down the southeast edge of the lake to stitch together the previous two lake edge scans. But it involved moving through the limnological LTER zone. For security we left the data fiber attached to the vehicle (but not connected to mission control), so we again used the pivot point (tube) west of E10 to ward the fiber away from the limno cables.

The entire crew was on the way to the Bot Garage at 9:45am. By 12:30pm the mission was underway and ice-picking positive buoyancy checks At 12:35pm Vickie disconnected the data fiber. The bot was on its own. In order to keep some measure of what was happening Kristof and Bill proceeded to follow the vehicle using the thru-ice tracking system. They proceeded directly to the E16 sonde cast location (using GPS to re-locate it since the flags had already been retrieved after the surface fix was achieved). The vehicle proceeded smoothly down the southeast shore to B8, which was well behind the prior limno “no fly” zone. We were again using the PVC pivot tube (small red circle about 140 meters southwest of E10—see mission plan figure). All proceeded according to the program and at 3:30pm the vehicle returned to the melt hole with sub-meter navigation error.

Vickie prepares to free the bot.

The deed is done and ENDURANCE is running fully autonomously, without supervision from mission control.

Results of the November 29th lake edge bathymetry mission. Only 1/100th of the points acquired are plotted here.

Chris subsequently ran a few automated sonde casts at F6 to test new code that integrated several auxiliary sonar systems to augment the altimeter on the Sonde instrument pod. The remainder of the time until 8pm was used to calibrate the Sonde depth sensor. Kristof and Shilpa read off the precise descent distance (using a metric fiberglass tape) while Chris stepped the Sonde downward via software commands. Bill recorded the encoder ticks and the pressure sensor readings. With these entered into a spreadsheet we were able to develop a very accurate compensation system with which the Sonde altimeter readings, and those of alternative sonar soundings from other instruments, could be correlated. We planned to test this new concept following the December 3 mission.

With the bot suspended out of the water, the Sonde pod is lowered to lake bottom with a metric tape trailing behind. This external reference provided an absolute scale against which to calibrate several onboard sensors including the drum encoder for the spooler, the pressure sensors on the Sonde, and the down-look altimeter on the Sonde. These would later be fused in a new filter for enhanced autonomous bathymetry tests.

The planning for the next few day’s bathymetry missions meant post-processing all of the prior data (scores of gigabytes, including that from 2008), importing those into the mission planner, and then developing paths to assure we had as close to 100% lake bottom and ice cap topography as possible. Chris wrote code to decimate the bathymetry data while Bill did the mission planning. Both were up past 3am.

Reporting by Bill Stone

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

Mission Objective: clean up bathymetry gaps in the northwest quadrant of West Lake Bonney. Conduct instrument alignment patch and crossing tests.

The team was up at 9am (less than 6 hours sleep for Chris and Bill) and back at the mission planning task. At 10am Kristof delivered decimated data sets for the Narrows and the southwest quadrant shore scans. These were imported into the mission planner and work continued until 2pm. Bathymetry Mission 4 was a complicated, “gerrymandered” trajectory designed to accomplish the dual tasks of filling in the gaps in the 2008 bathymetry data in the northwest quadrant and, as well, to acquire data that would be used to calibrate local yaw, pitch, and roll for various critical mapping instruments. The main multi-beam imaging system was moved from its forward-looking mapping and obstacle avoidance position to a down look orientation for swath bathymetry mapping.

Kristof (left), Vickie, Rachel, Shilpa, and Chris go over the November 30th mission plan.

Prior to November 30, 2009 this was the plan extent of the bathymetry that has been acquired for West Lake Bonney and represents a composite of all 2008 and 2009 missions to date that collected bottom topography information. The blue polygon-enclosed areas represent gaps in the data set. Our goal was to fill these in to the maximum extent and leave no gap greater than 25 meters.

The gerrymandered mission of November 30 was meant to sweep out all of the blue polygon gap areas shown and, as well, to conduct calibration tests that would acquire data needed to align the critical mapping sensors in yaw, pitch, and roll relative to the vehicle coordinate system. The “patch” test used segments BA22-BA23 and BA24-BA25; the “crossing” test used segment BA35-BA36 in conjunction with BA30-BA31 and BA32-BA33.

By 2:40pm the bot was down hole and on its way. As soon as it cleared the positive buoyancy test Vickie disconnected the fiber and the next fully autonomous mission was underway. Kristof took a turn out on the ice with tracking the bot in real-time. Five hours later, having run the maze-like mission, the bot found the melt hole, locked onto the light beam and surfaced on its own. The entire mission had proceeded flawlessly with a run time of 3.8 hours underwater (4.8 hours total in-water mission time). The total underwater traverse was 3,481 meters. We had, using the mission planner, conservatively predicted 27% power reserves at this point; the actual reserve was 35% at surfacing.

Vickie breaks the data link to the vehicle for the second day in a row. From this point forward the vehicle was fully autonomous.

Given that we still had substantial power remaining, the vehicle was re-ballasted for neutral running at 5 meters and sent to station F6. A series of cast tests were conducted there (fully automated drops) using a simple control filter comprised of the Profiler encoder, the Sonde altimeter, and the Doppler vertical ranging. We will later include the following additional auxiliary sensed data to the control filter: bot depth sensors (meters); sonde depth sensor (meters); nadir obstacle avoidance sonar (meters to bottom); and central multi-beam range (meters to bottom).

At 8:54pm the bot returned to the melt hole, locked onto the guidance light beam and rose up the hole. The bathymetry data were downloaded and subsequently plotted later in the evening. These revealed some curious behavior in the data. In the central portion of the lake we obtained nearly 100% of the intended topographic fill content we were seeking. However, in the shallows along the northwest shore the acoustic reflectance characteristics of the lake bottom were significantly different, and the valid range returns from the multi-beam comprised a narrower swath than was originally expected. The instrument in question had software selectable range gating and signal gain adjustments, but these are frequently sensitive and too much gain, which would have led to a wider return swath, would have resulted in noisier, less accurate measurements unless the range gates were appropriately set. This process, currently, is something best done by a human while observing the data feedback. It would have been caught immediately had this been a human-supervised autonomous mission, as we had until now been running. It pointed to the limitations of a robotic system in a purely autonomous setting. Silicon intelligence only responds to that which it is programmed to perceive plus a few simple behaviors driven by direct sensed and derivative data.

Bathymetry fill results from the November 30 fully autonomous mission. Nearly complete fill was achieved at the center of the lake; less coverage (but still acceptable) was obtained in the shallows towards the northwest shore, largely because of a reduction in the acoustic reflectance of the material in that area.

Shilpa retrieves the iUSBL transponder prior to arrival of the bot. Since the data fiber was disconnected, we tracked the bot position using the through-ice emergency beacon. Kristof, who was on duty, radioed the message to Shilpa who pulled the beacon just as the bot arrived under the melt hole.

Returning home, image 1 of 3: the bot crosses the melt hole at a depth of 5 meters.

Returning home, image 2 of 3: the bot locks onto the central guide light beam.

Returning home, image 3 of 3: the bot surfaces, still locked onto the central beam.

Reporting by Bill Stone

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

Mission Objective: Southwest quadrant bathymetry cleanup.

The main portion of the team was up at 8:30am and off to the bot garage. The late team (who planned yesterday’s mission at 3am) of Chris and Bill slept in till 10:30am then came to the lab at 11:30am along with Marianne Okal from UNAVCO. Marianne would be running a series of LADAR scans of Taylor Glacier and the Bonney Riegel narrows to complement the underwater 3D map. Together these would form a permanent 3D temporal record of the geo-spatial topography of these features at this point in time.

Marianne Okal sets up for another LADAR scan at Taylor Glacier. The far tripod, with its white sphere, is part of the geo-registration system. Three of these spheres, whose GPS position is known, are positioned within each scan frame and the laser ranges to these spheres form a unique registration solution to the position and orientation of the LADAR. Like the underwater 3D data, we use UTM (Easting, Northing, and Elevation, in meters) as the reference coordinate system.

At noon there was an exclamation from Shilpa at Mission Control that the internet was back up… following another 7-day absence. There was a momentary stuttering halt to the mission checklist while everyone dashed to check their email. By 1pm all of the system checks had been cleared and the bot was underway on Bathymetry Mission #5. The mission plan (see figure) was as similarly complicated as the previous mop up missions, with the effort being to fill in the gaps from the previous surveys. In this regard it is worth pointing out that there was no apriori “most-efficient” method currently developed (by us or anyone else) for bathymetry mapping of an unexplored sub-glacial lake. The approach we took in 2008 was that the Sonde chemistry casts took highest priority; the initial scanning and exploration of the underwater entry of Taylor glacier into West Lake Bonney second priority; and, finally, to fill in bathymetry and improve the extremely limited knowledge of the lake bottom topography (obtained by the few wire drops that had been performed before 2008) as a “target of opportunity”. We took the philosophy in 2008 that we would mount the multi-beam imager in down-look mode and take what we could get in the form of bathymetry while otherwise getting the Sonde data. Fortuitously, we now knew from the successfully completed 2008 sonde missions what the topography looked like and were now able to go about a concerted program to fill in the gaps. The approaches we have selected to the November 30, December 1, 2, 3, and 4 missions have sought to fill in the gaps with the least number of missions. These have resulted in the “gerrymandered” shape to some missions, today’s included.

Bathymetry Mission 5, on December 1, 2009 was another “gerrymandered” convoluted route to fill in gaps in the lake bottom topography left by prior missions. The total mission length was 3,352 meters with an under-ice transit time of 3.6 hours (total of 4.6 hours in the water).

By 2pm the vehicle was at waypoint BA47. There was no surface tracking this time although we did keep the data link up. The only human input on the mission was to adjust the multi-beam range and gain settings to gain the maximum low-noise bathymetry data. This “supervised autonomy” approach worked well (as it has in the past) and the swath widths (and fill factor in the targeted regions) were maximized throughout the mission. By 4:12pm the vehicle was back at the melt hole, locked on, and auto-surfaced. We then submerged again and returned to F6 for further testing of the DVL-assisted auto-sonde drop code that Chris had developed. By 6:16pm the bot was back on charge on its carrier sled in the lab and the data were being downloaded. Bill completed the mission plan for December 2 and this was distributed for comment. Since this would again push the system to its limits (through the Bonney Riegel narrows) efforts were undertaken to balance the battery stacks and achieve maximum accessible charge. By 8:06pm the batteries were out of the vehicle and being manually balanced; by 8:37 pm the imbalances had been corrected and the full stacks were put on a 3.25 amp charge for the night. The canisters were left open for a final balance in the morning.

Supervised autonomy (with mission control actively modifying the range gating and gain on the multi-beam scanner) resulted in a nearly 100% fill factor in the targeted gap regions of the map. Extreme under-keep shallows prevented absolute coverage in the far western section of the map. In some places less than 2 meters of clearance under the vehicle existed—the lake shallows up considerably west of the A4-C4 line.

Going for maximum performance for the December 2 Narrows mission, the individual battery stacks are manually balanced prior to full charging.

Reporting by Bill Stone

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

Mission Objective: Narrows sonde mission temporal duplicate run (to capture the effects on water chemistry through the connecting sill between East and West Lake Bonney due to melt water runoff since the last run through the narrows on November 18th).

The crew was up at 6:30am working on data reduction and blogs and at the bot lab by 9:30am. At 10am Kristof delivered to Bill the previous mission’s ice picking pose coordinates. These were re-plotted in the mission planner to obtain the true location for NR7. This particular location had been moved 50 meters further into East Lake Bonney at John Priscu’s request on the original November 18th narrows mission. Since we now had GPS locations for the true points, these were used to establish the target waypoints for today. The batteries completed charging and were re-installed into the vehicle at 11:23am. By 12:13pm the bot was back together and on top-off charging. The IMU was aligning and the mission plan was uploaded. At 12:40pm the bot was underway to the narrows following an initial failed attempt at ice-picking adjacent the melt hole. Ice picking was one of our final checks before releasing the vehicle on a mission. In this case the vehicle was too heavy and would not float up under the ice—a requirement on all our Sonde missions for conservation of energy while conducting the sonde cast. We commanded the vehicle back up the hole, removed a kilogram of lead and sent it back down. This time it passed the ice pick test and we sent it on its way.

Chris tests the stack balances in the batteries before they are re-loaded into the vehicle for the December 2, 2009 mission to the Bonney Riegel narrows.

The mission plan was similar to the November 18th run with the significant changes in vehicle path at both the beginning and end to accommodate filling in missing gaps in the bathymetry data. Specifically the vehicle was targeted north to BA60 to BA63 on the outbound mission and to BA64 to BA67 on the return. The sonde casts through the narrows were identical to the prior mission.

At 2pm the bot reached the pivot target R2 just north of the Narrows. The navigation was off by 2.5 meters and Bill and Vickie on the ice tracking team reported this via radio to mission control. This was not enough error to cause any problems with the fiber diversion system (in place at waypoint “Pivot 2”) but by the time it reached the first scheduled sonde cast waypoint, NR2, the error had grown to 4.5 meters. The ice tracking team re-vectored the bot to the waypoint and the GPS coordinates were uploaded to the navigation solution, essentially re-initializing it to those known coordinates. The mission proceeded on schedule and on target from that point forward. By 6:15pm the bot was a half kilometer from the melt hole, having acquired all of the sonde casts at NR1 through NR8 and carrying a battery reserve of 32%. By 6:23pm it was 150m from base with 28% reserve. At 6:40pm the bot found the melt hole and automatically began its ascent. The auto-docking sequence was halted and the vehicle was put into station keeping mode while a new set of instructions relating to automated sonde cast testing was uploaded. The vehicle was then sent back down and retargeted to F6 where a fully-automated sonde cast was successfully accomplished using the new sensor fusion code. A full test of this new system was scheduled to take place at the conclusion of tomorrow’s final bathymetry mission. By 7:18pm the bot was back at the lab.

Vickie tracks the bot in real-time with RTK-GPS during the December 2, 2009 mission through the Bonney Riegel narrows.

The full picture of the narrows with Bill Stone standing directly above where Scott’s party stood in 1903 (with 16.2 meters in water level rise). See the November 18th, 2009 log entry for a cross section plot at this location.

Vickie Siegel acquires the last of the GPS fixes for the sonde cast waypoints. With an 80 minute transit time for the bot to return from the pivot point at R2 to the melt hole, the ice tracking team retrieved the white pivot tube (seen attached to the ATV), collected the remaining flag markers, and their coordinates.

In a post-mission debriefing we discussed the navigation error at NR2. Kristof hypothesized that it was due to the fact that the bot failed the first test for ice picking at the start of the mission. It was brought back and some lead was pulled off. Normally, once the navigation solution was acquired and the bot launched the vehicle moved in a smooth succession with all sensors acquiring data. Aside from eating up power (which proved to not be a problem) the apparent problem had been that the navigation solution had been updated without the benefit of several key sensors—which were shielded by the melt hole. Without those sensors in the loop, the position estimate was coming only from doubly-integrated accelerometer data, which is known to drift over time even with the very high grade accelerometers installed in ENDURANCE. This was enough to inject both a positional error of several meters and a slight angular misalignment at the re-start of the mission and this extended to NR2 where we reset the solution to the absolute coordinates there (acquired by GPS). With the main nav sensors operating the solution maintained lock for the remainder of the mission. The total under-ice run length, not counting the excursion to F6, came to 3,982 m today with an under-ice mission duration of 5.6 hours. The sonde cast data were excellent and formed a complete data set with which to compare to the set acquired three weeks earlier.

Lake bottom bathymetry was paved in and on target, mopping up the last of the gaps in the eastern half of West Lake Bonney. Only the area southeast of the limnological experiment zone remained to be scanned.

Reporting by Bill Stone

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

Mission Objective: Limno “no fly” zone bathymetry cleanup—final mission 2009; auxiliary navigation experiments; autonomous automated sonde mission down deep axis of lake if energy remains.

After a considerable amount of discussion and planning we sought to wrap up all remaining data collection and vehicle control experiments for 2009 in one final mission. The primary objective was to fill in the bathymetry map southeast of the LTER limnological cables. For this we would have to employ the diversion pole for the 4th time. The mission profile was complex and contorted and we hoped to fill in some of the northwest gaps left over from the November 30th mission. Last, we planned to test the finalized sensor-fusion Sonde cast system on a short mission down the deep axis of the lake through waypoints AC01 and AC02.

The complex December 3, 2009 bathymetry mission had as its initial objective the completion of lake floor mapping southeast of the LTER limno cables (shown as a cluster of four maroon spots south of AC02). It then proceeded north to fill in gaps in the November 30th mapping zone, and finally ended with automated sonde tests east of the melt hole.

The final mission was uploaded at 11:15am and the vehicle as in the water and neutrally ballasted 21 minutes later. The vehicle subsequently failed the ice-picking test at 11:48am and we brought it back and removed 1 kg of ballast, this time taking the precautionary measure of locking the nav solution prior to ascent through the melt hole. This procedure subsequently proved effective. The mission proceeded smoothly and it was supervised, although not interfered with, at mission control throughout the entire run.

Chris (right) continues work on the enhanced sensor-fusion automated-sonde code while Shilpa and Kristof monitor today’s mission.

The issue of the changing ballast requirements has remained one of the curious mysteries of working in Lake Bonney. From day to day—and even during the conduct of a mission—and with no physical changes to the vehicle from one mission to the next, the buoyancy has been seen to vary as much as 10 kg. Originally this was thought to be a result of the “microbubble” phenomenon discovered here in 2008. There, we believed that super-saturated gas dissolved in the water was allowed to leave solution due to the pressure drop associated locally with the vehicle’s thruster props. It would frequently adhere to the vehicle skin as white fuzz. This, however, had the effect of increasing the buoyancy of the vehicle, which altogether was not a problem for Sonde missions. The issue of increasing negative buoyancy following an otherwise positively buoyant state in the melt hole could potentially be explained by cold shrinkage of electronics housing and flotation or possibly by trapped bubbles compressing with greater depth. But great efforts were undertaken at the start of each mission to “burp” the vehicle of any trapped gas. So this issue remains for consideration for future sub-glacial autonomous systems operations.

At 4pm the bot detected a very large boulder on the north shore of the lake, on the order of 10 meters in diameter. At 4:35pm Mission Control interceded in the mission in a planned test of one of the auxiliary navigation systems (the iUSBL). In this test Mission Control induced a failure state in which the dead-reckoning navigation system went off-line. The vehicle control system picked up on this and successfully navigated back to the melt hole on the iUSBL system for the remaining 150 meters of this first part of the mission. By 4:44 pm we initiated the second half of the mission: an autonomous sonde run east of the lab. With no intervention the bot conducted fully automated sonde casts at F6, AC03, and AC04 (parallel to, but offset to the north of AC01 and AC02). Also, given that a large rock had been detected in this zone on the outbound journey to the limno zone we were able to use this information for further fine tuning of the roll calibration on the imaging sensors. Total mission length for today, not including the final sonde run, was 3,318 meters with 4.3 hours of under-ice time. With this mission complete the 3D geometry of sub-surface West Lake Bonney was complete (see figure). As of 6pm today, with the bot safely back, all mission objectives set forth for the ENDURANCE project had been met and in most cases exceeded by substantial margins.

Results of today’s supervised autonomous bathymetry mission. Complete coverage (and more) was achieved in all target zones (shown by the blue polygons).

By 6:21pm the moon pool cover had been closed for the final time and a group photo of Team ENDURANCE 2009 was taken. The rails were disassembled and taken outside. The Sonde was removed and packed. By 8:04pm the four syntactic flotation quads were in their yellow shipping transport cases and moved 50 meters west of the bot garage, within helo pickup range. All of the battery stacks (5 of them) were packed and stacked. At 8:30pm the 10 kW diesel base generator was powered down for the final time and we drove back to the Jamesway at ELB. Just two days of packing and break down remain in Taylor valley.

The composite result of all bathymetric data acquired in 2008 and 2009 by ENDURANCE. The entirety of West Lake Bonney is mapped along with the Bonney Riegel Narrows (where Scott’s party passed in 1903) as well as several hundred meters out into East Lake Bonney. There are other data, from obstacle avoidance sonar as well as glacial mapping from 2008 that are not shown here that fill in remaining sections up to the face of Taylor glacier. In all the map represents several hundred million measurements and by orders of magnitude is the most detailed map of any sub-glacial lake currently known.

Left to Right: Kristof Richmond, Chris Flesher, Emma Steger, Vickie Siegel, Rachel Price, Shilpa Gulati, Peter Doran, and Bill Stone.

Reporting by Bill Stone

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

The crew was up and at the lab at 8am and facing the substantial task of breaking everything down that had been set up for the past six weeks and getting it into the appropriate shipping containers, “Triwalls,” and readied to be lashed into cargo nets for pick up by the helo fleet that would now be visiting us like mosquitos on a hot summer evening.

Vickie, Emma, and Rachel disassemble the bot instruments for safe packing.

Looking like a quartet of killer whales breaching the surface for breath, the bot syntactic sits on a sea of frozen ice on West Lake Bonney, awaiting closure for helo pickup.

Chris, Kristof, and Shilpa re-load 2 kilometers of fiber optic data comm line for retro to CONUS.

By 4pm the first half of the team was heading back to ELB camp to begin packing up personal things in preparation for tomorrow’s expected retro to McMurdo. Along the way to ELB a team of four from the carpentry shop led by Chad McNaughton passed on their way to begin preparation of helo sling loads for the cargo boxes that our team had assembled. Several loads left for McMurdo today including all of our diving gear and a compressor in one sling under a B212. It was like Anti-Cargo-Cult mysticism… You laid out the loads on the ice and they disappeared before sunset. It was always impressive to watch when the McMurdo helo fleet kicked in. And to them we owe a debt of gratitude for their awesome service both in 2008 and 2009.

Bell 212 Helo “Oh-Eight-Hotel” carries a half ton of diving gear out in one lift.

There was one final piece of unfinished business for some of us. After having stared at the looming Matterhorn peak (see November 5, 6, and 22nd logs), 1860 vertical meters above our camp, everyday for 6 weeks and with precious few hours left this year before departure, Kristof, Chris, and Bill set off to climb it at 5pm. The weather was stark clear and the wind had died. Despite the good weather the three each carried ECW gear, food, water, and radios. Six hours later they reached a point about 200 vertical meters below the summit and found the route too steep with snow and ice to safely continue without technical ice gear. The view, from a vertical mile above camp, well above the southern Kukri Hills that flanked Taylor Valley, was one that would last in memory forever. The absolute pristine beauty, the stark geometry of rock and ice, of banded exposed geology, and the vista that went for more than a hundred miles, was stunning. We could see over the Kukri Hills to the south and beyond the Asgard Range to the north. McMurdo Sound was visible to the east. The descent was swift and sure and the team was back by 2am, in time to celebrate the return of Maciek Obryk and Jim Olech to ELB. They would help us take down the bot garage in the morning.

Chris (left) and Kristof make their way up the final basalt, dark-rock summit pyramid on the Matterhorn. Far below is the Matterhorn Glacier which, itself, is close to 800 meters above East Lake Bonney, far, far below.

A forever view looking north into the Asgard Range from near the summit of the Matterhorn.

A bizarre wind-eroded basalt pillar ventifact some 200 meters below the summit of the Matterhorn gives the appearance of a host of spirit faces scrutinizing the arrival of the climbing team. The angular distortion is deceiving—the pillar is actually vertical and the boulder slope is close to 45-degrees to the vertical.

Reporting by Bill Stone

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

At 7am Peter Doran came around to every tent in East Lake Bonney camp and woke the crew up one by one. Despite the cloud cap the word from McMurdo was that the helos were flying, and there was much to do today. Everyone crash packed their tent, sleeping bags, pads, personal clothes, and ECW by 8am and had lugged them down to a growing pile below the helipad just east of the Jamesway. At 8:10am Vickie, Rachel, Bill, Maciek, and Jim headed for the bot garage to join the carpentry crew for the dismantling of the now-empty lab structure. Kristof, Chris, Peter, and Shilpa were scheduled for the first helo flight back to McMurdo and stayed at ELB to pack.

By noon the tarps, insulation blankets and framing (tubes) were all down and boxed. We used a rolling scaffold with two persons on top and two ladders on the mid-sides.
We had to move the bot (on its sled) to the side of the platform to allow passage of the scaffold; otherwise it all went well. The carp team remained on site handling the preparation of sling loads for several more helo lifts expected in the afternoon. For our team, however, it was time to quickly retreat to ELB camp and make one last pass through the Jamesway to ensure everything was packed. It was time to go meet our science cargo back in McMurdo.

Maciek removes one of 17 mylar thermal blankets from the bot garage siding.

The interior, final shell of the bot garage presses against the tube frame in the up-valley wind.

With the superstructure of the bot garage stripped away and all of the science gear packed in cargo crates and sling loads, ENDURANCE stands alone in its own ECW gear, awaiting pickup.

The art of Antarctic Dry Valley conservation: Vickie, Rachel, Maciek, and Jim cart off seven 5-gallon bio-hazard drums of human waste from the yellow pyramidal Scott tent outhouse by the bot garage. The orange 55 gallon drums contain six weeks of urine. Nothing is left behind.

A B-212 helo dropped in on ELB camp around 2:20pm. We had already hauled all our bags up and had them sitting beneath the helo pad so it was a matter of putting on ECW jackets and white boots and running up. They handed out helmets and we crammed six of us in the back along with all our orange bags (sleeping kits had been left under the helo pad for later pickup).

Packing out: personal helo bags (orange) stack up outside the ELB Jamesway on December 5th. Each person gets two such bags. Science cargo goes separate.

The final hike to the helo pad for the ride back to McMurdo. Six people in full ECW gear with their personal belongings fit into the B212.

The housing office handed out keys when we arrived. Some people fared worse than others in the lottery: Kristof, Chris, Maciek, and Jim got bunks in the infamous Hotel California. Emma and Shilpa, on the other hand, got their own rooms in Building 203. So ended the 2009 field season. For some of, however, it would be another week in McMurdo, packing equipment for retro to CONUS.

Reporting by Bill Stone

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

Sunday is “brunch” day at McMurdo Station, so the team met for breakfast at 11am before going their separate ways to begin sorting out their various chores and responsibilities. Four of our crew (Peter, Shilpa, Kristof, and Chris) were scheduled to leave on the C17 flight on the 8th, in just two days, so they were more pressed for time than the rest to resolve any open issues in town (a lot of equipment had to be returned to various labs; offices had to be cleaned up and gear stowed; data had to be backed up; and any excess personal cargo had to be boxed and shipped).

Peter Doran and Bill Stone presented the Sunday Night Science Lecture at McMurdo to a crowd of about 150 in the main dining hall in Building 155. These lectures are a frequent place to catch up on what other field researchers have underway, what conditions exist out on the ice, and what logistics problems are currently at hand. Even as our team was leaving Taylor Valley, other crews were coming in for their 2-month projects.

Sunday Night Science Lecture series poster for December 6, 2009.

Peter Doran describes some unusual Sonde down-look camera images from West Lake Bonney at the Sunday night lecture.

Reporting by Bill Stone

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

At a 7:15am breakfast the team discussed the current status of our equipment. The bot, the two yellow shipping containers with the syntactic flotation blocks, and two heavy gray shipping containers full of instrumentation and power supplies were still at Marble Point, some 45 minutes by helo away from MCM. These were scheduled to arrive today (gray boxes at 5:35pm on 36H; bot at 10:20am from WLB on 08H; then several white science cargo shipping containers with such things as left over food, dive lead, ice axes, ropes, heaters, rigging hardware, tables, chairs, and the like from Marble at 10:25am on 36J; and two yellow boxes from Marble at 12:40 and 2:45pm also on 36J). Of these, the gray boxes failed to materialize due to deteriorating weather along with one of the yellow crates.

Science lab space, particularly space with an overhead crane, is at an absolute premium in McMurdo during the austral summer, when scores of large projects are passing through and returning to the base from further inland. We were not surprised, therefore, to find that neither our original work area of 2008 in the MEC complex, nor our more recent “A-Team” set-like staging locality for 2009 in the Incinerator building were available upon our return. There were some eyebrows raised, however, when we were issued a key to Building 126, where the bot and our gear would be warehoused until their shipment back to CONUS sometime in January. The building was located halfway up Ob Hill, where the old “SLOWPOKE” reactor had been located, in a building scheduled for demolition—due to asbestos. The place had a thick layer of dust over all surfaces with cracking plywood and deformed, rusting metal plate floors. It was being used for temporary storage of large, mostly black-painted, wood boxes and Triwalls and gave the strong subliminal impression of a 1930s era warehouse where gangsters would have had a shoot out with Tommy guns. The fact that it had been a part of the old reactor complex did nothing to dispel the ambiance. In the late 1950s the Navy, which had first established McMurdo as part of the original “Operation Deep Freeze”, decided that nuclear power was the solution to the base’s growing diesel consumption. The PM-3A, NNPU “Nukey Poo” US Navy power reactor produced 1.75 megawatts of electrical power, and, as well, provided heating and desalinization power. Initial criticality was achieved on March 3, 1962. It was “decommissioned” (shut down, due to chloride metal corrosion) in 1972. It operated on 93% enriched U235. The reactor, its associated building, and 9,000 cubic meters of irradiated foundation were retro’d to CONUS by 1979. Further fascinating reading on this topic can be had here:

The Antarctic Environmental Awareness Page at Southpolestation.com (not an official USAP website)

SLOWPOKE Reactor Wikipedia Entry

1950s photo showing the SLOWPOKE reactor complex on Ob Hill. In 2009 Team ENDURANCE used the right-most building for equipment re-packaging for retro to CONUS.

At 1:10pm we drove up to Building 126 and not long thereafter Tony Buchanan from MEC arrived with the bot from helo ops on a trailer. A large fork truck also arrived with a long extender “Y” shaped gadget that went on the forks to make a shackle suspension point. Using that they picked the bot off the trailer and dropped it in the building inside the role up door. Later Michael Davis at Science Cargo located the big crate ENDURANCE had been shipped in from Port Hueneme and brought that up on a large “duty fork”. We later had to request a “pickle” (green Mk4 2-ton capacity small fork truck) to come up to move this inside along with one of the yellow boxes.

A final team meeting was held at 3:30pm in Crary to discuss 2009 completion tasks. In addition to the above activities, throughout the day materiel was being returned to such places as the BFC, the field outfitting center. This included all of our sleeping bags, cook sets, and… pee bottles (no waste of any kind is allowed to touch the ground in the Dry Valleys). With regard to the last item, each person was responsible for cleaning their own bottles at the “Garofalo Memorial Pee Bottle Sink”.

Shilpa gets her turn at using the Garofalo Memorial Pee Bottle Sink in the Berg Field Center.

Also at the BFC, Emma returns unused human waste buckets.

Later in the evening a final Team ENDURANCE departure party was held at the Southern Exposure bar.

Reporting by Bill Stone

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

Following a team breakfast we bade farewell to Peter, Shilpa, Kristof, and Chris. They hiked off to the post office at 11:40am for pickup to the Pegasus ice runway and the waiting C17 for the ride back to Christchurch. The remaining members of the crew (Maciek, Jim, Vickie, Rachel, and Bill) met at Crary at 1pm and drove up to Building 126 to continue breakdown, sorting, and re-packing of the shipping containers.

We spent the afternoon setting up the lightweight gantry that had been used at the glacier melt hole, laying down the 6 inch steel channel rails for it, and getting the hoist loaded onto the trolley (a not-inconsequential feat given that the hoist weighed over 50 kg). We then picked up the bot for placement on its heavy wooden shipping pallet. Next came the four orange syntactic flotation quadrants (they had been removed for helo flight due to load restrictions; there were no such restrictions on the C17 so we re-assembled most of the durable systems into the bot frame. The expensive, sensitive electronics and sensors went in their own shipping containers. With the bot tied down on the pallet, we then turned the job of completing the giant box sidewalls and top to the more capable hands at the carp shop, who had been unendingly helpful this entire season. We plan to meet with them tomorrow to go over the bolt up procedures.

At that point what remained was to empty two large “Triwalls”—large 3-layer corrugated cardboard shipping boxes—into which we had dumped a good portion of our science cargo hastily at Lake Bonney and repack that load into the two now-empty yellow boxes. We put the lead on the bottom. There was a small debate over setting up the gantry to pull boxes out of the Triwalls (the men favored just jumping in and passing them out; the women wanted to use the hoist. As they had a 3:2 majority the men were chastened to finish their work at Crary while the others completed the transfer and the Rubic’s Cube dense packing. Around 5:30pm a call was received in Crary and the truck was driven back up Ob Hill to retrieve the three women. Everyone went to dinner then and retired early. While having more diverse and plentiful food, McMurdo certainly lacked the ambience that made staying up late and working at Bonney a pleasure.

Inside Building 126 on Ob Hill, Vickie, Rachel, and Bill repack the ENDURANCE shipping containers for maximum density.

Reporting by Bill Stone

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

Some of us were up at 6am working on data reduction and blog postings. There was a small team meeting at breakfast at 7:15am. Emma and Jim helo’d back to West Lake Bonney today to pack up the last remaining BFC items (tables, chairs, stove, heaters) contained in a small auxiliary Jamesway hut that had been erected adjacent the bot lab during the original set up in October. There had been a mis-communication last Saturday with the carp crew there about who would wrap that part up and so this last bit somehow never got done. Since no one gets cleared to leave MCM without cleaning up their field camp mess, back we went.

We spent the morning doing an inventory of all equipment in the two large yellow shipping containers. At 1pm we assembled a critical mass of crew at Building 126 and took down the hoist and gantry then transported that by truck back to the MEC shop. By 4pm we had the two yellow shipping crates closed up and cargo-strapped, ready for transport. We picked up the carpentry foreman over at the Carp Shop and went back to Ob Hill to discuss proper tie down procedures for shipping the bot as well as the bolt up of the sidewalls and top to the giant crate that went around it. We returned at 5:30pm and met the rest of the crew for dinner, including Emma and Jim who had successfully completed their mission to WLB.

First to go: ENDURANCE Li-ion power stacks at Science Cargo, ready for retro to CONUS.

This evening everyone spent time sorting through their ECW gear for tomorrow’s bag drag. The remaining six of Team ENDURANCE (Maciek Obryk, Jim Olech, Emma Steger, Vickie Siegel, Rachel Price, and Bill Stone) were now on the manifest for the December 11th C17 flight to Christchurch. Personal gear sorting at the end of a season is somewhat tedious. MCM gives you up to 70 kg of checked baggage but only one orange hand bag to carry on board, which includes your laptop. There is also a similar small orange bag that you can pack with emergency clothing in the event the flight “boomerangs” (has to abort and return to MCM due to weather or mechanical issues). The rest stays locked down in the cargo nets if the flight returns so you have to anticipated that if things go wrong you will be living with those two small orange bags for some time, hence the considered packing exercise.

Reporting by Bill Stone

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

The crew was up at 7am and met for breakfast at the Building 155 galley. The last of the BFC gear (sleeping bags, missing pee bottles, water bottles, food, and ice rigging gear) was collected, cleaned and returned, closing our tab at the Berg Field Center.

A final bolt-down of the syntactic to the bot took place up in Building 126 on Ob Hill. We used a pallet jack to move the 700 kg (each) yellow shipping crates to where they could be snatched by a “pickle” fork truck and taken to Science Cargo. By mid afternoon all our shipping crates were checked in at Science Cargo (including a large toolbox, the two yellow crates, and the two gray boxes that had finally come in from Marble Point as a one-stack pallet). The bot remained in Building 126 until the carps completed the crate around it. Science Cargo indicated that the bot, along with a science UAV (unmanned aerial vehicle) would be going back on a dedicated C17 at the end of January.

Rachel poses in front of the bot inside Building 126 on Ob Hill.

We spent the rest of the day cleaning up our rooms, packing, completing blog entries, and closing out our offices in Crary Lab. At 8pm we did the ritual “bag drag” up to the post office building where flight loads were prepared. Given the amount of field gear we had brought with us it took two heavily-laden trips per person.

Vickie backpacks a double load on the first bag drag haul to the flight staging area at the post office building.

Reporting by Bill Stone

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

Everything happened fast today. We had breakfast at 7am as usual then off to Crary to track last minute clean up issues (key returns, lab clean up, packing). We arrived at the mailroom at 11:30am amidst a growing crowd of people decked out in their full ECW gear (see October 6 blog entry). The group, probably 60 total, was enough that they crammed 18 of us into a Delta (which was a forced fit from any viewpoint) and had to load the rest into Ivan the Terrabus, which was also packed tight.

Rachel, Vickie, and about 40 others fill Ivan the Terrabus on the ride to Pegasus ice runway.

We arrived at the Pegasus ice runway site around 1:00pm and waited around for at least an hour and a half for the C17 to arrive. They first offloaded an amazing number of pallets, the last of which was a good 15m long—antennas for an experiment up on arrival heights. Then they loaded our grey and yellow boxes. Then us. We were in the air by 3:30pm and arrived in CHC around 9pm. The five and a half hour C17 flight was definitely to be preferred to the C130 we came back on the previous year, which averages around a 10-hour trip. It was nightfall when we arrived, something we had not seen for the past 2-1/2 months. And it was green. Green like you would not imagine except in some soap commercial shot in Ireland.

Pegasus refugees wait for the C17 on the ice runway. Pegasus is located on the Ross Ice Shelf proper, where the ice is permanently stable. But it is a long haul from McMurdo station—typically a 45 minute to 1 hour journey by Delta. Earlier in the season the sea ice in front of McMurdo is stable enough to use and the C17 can come within 500 meters of the base.

ENDURANCE gear on its pallet, waiting to be loaded into the C17. The strange looking vehicle in the background is used to compact the runway.

The “freedom bird” arrives.

C17 touching down on Pegasus.

C17 on ground approach for off-loading.

ENDURANCE shipping containers get loaded onto the C17.

Reporting by Bill Stone