Stone Aerospace

Forward Momentum

We made some great strides with ARTEMIS yesterday. Buoyancy trim is still not perfect (ARTEMIS has a slight lean to starboard), but after Saturday’s adjustments, the vehicle was sitting level enough yesterday that we were able to perform a 10 hour dive with some exciting results. We:

• drove ARTEMIS around under the sea ice near our camp
• tuned autonomous control loops and tested our new buoyancy-compensating feedforward control
• tested scripting of autonomous motions
• localized ARTEMIS from the surface using the magnetic tracking system
• displayed live science telemetry in the bot house
• docked ARTEMIS to the lighted docking bar under joystick control
• recovered ARTEMIS to the surface using the docking bar rigging​

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Here are some photos of the surface tracking operations led by Brian. Brian was pleased with the tracking system performance through the ice, and was able to localize ARTEMIS even at 35 m water depth. In these pictures, try to imagine 7 m of sea ice and brash ice underneath the feet of the tracking team, with ARTEMIS at 35 m water depth, and the bottom of the Ross Sea 700 m below.

The docking bar test was very exciting. I was “at the wheel” driving ARTEMIS onto the bar. The system worked very well, and now we’ve got our first set of images of the docking bar under ice as seen by the actual ARTEMIS cameras. Evan is using these images to validate our automated visual docking system. The first fully-automated docking run will be a real milestone for our project, and we feel it getting very close. Here are some views from the ARTEMIS camera of the docking bar during our piloted approach and docking run.

Since the docking bar hangs straight down through the culvert (and is covered in super-bright LEDs), we can see ARTEMIS attached to it from the surface.

With so many exciting steps taken, group morale was very high at the end of yesterday’s dive. However, we are now feeling serious schedule pressure. As the austral summer advances, the sea ice beneath our camp will break up and blow out to sea. We have ambitious goals and only a few precious weeks remaining here on the ice.

Reporting by Peter Kimball

ARTEMIS Ballast Dive

We had our third ARTEMIS dive last night and made excellent progress on ballasting. We had to make a few changes to the ARTEMIS configuration between our last tests in Texas and our first dives here in McMurdo Sound. As a result, we’ve had to adjust the number and locations of ballast weights in ARTEMIS to get it to sit level in the water. Bill dove beneath the ice to make some ballast adjustments last night. We hope to complete ballasting with some adjustments in the bot house today.

Here’s a quick collection of clips form the GoPro we attached to Bill’s dive helmet last night.

We use a large weight attached to the tail to hold ARTEMIS in a vertical orientation for deployment and recovery through the culvert. The end of the video shows Bill attaching the recovery weight before turning around and surfacing through the fish hut culvert. The yellow, red, and black tubes are Bill’s surface air supply, communications, and pressure depth measurement.

ARTEMIS hangs in a vertical orientation with tail weight attached, ready for recovery. (photo: Bill Stone)

Reporting by Peter Kimball

Observation Tube

I went with Keith, Brian, and Justin to the McMurdo Sound observation tube today. Set up by the USAP a few hundred feet offshore, the observation tube is shaped like a large thermometer, with a roughly 25 foot descent through a pipe into a small bulb with windows. The pipe runs down through the sea ice, and the bulb windows provide a view into the water all around. The view is spectacular, but we all throught the sounds of the underwater environment were the highlight of the excursion. The high-pitched sounds of distant seals can be heard faintly in the tube.

Reporting by Peter Kimball

Stargates

It seems the life-on-other-worlds motivation for our project has settled into the subconscious of McMurdo. The word “stargate” has come up independently in multiple disparate contexts relating to our field work. In a field safety meeting, we described the flagged access route from our camp up onto the ice shelf as a “stargate”. Now, completely independently, the USAP carpenters have installed a really nice new stair access to the bot house, and called it STARGATE – the Sea-Ice To Artemis Robot Garage Advanced Terrestrial Entry. These stairs, their name, and their abundant labeling are all totally fantastic.

Meanwhile, the bot house drill hole took on a particularly “stargate” appearance last night as we lowered ARTEMIS (with its headlight on) out of the culvert and into the open ocean for the first time. We used the ARTEMIS thrusters to maneuver around the area beneath the culvert (still in a vertical orientation), and confirmed the result of our ballasting efforts based on the scale readings from the night before.

Vickie watches ARTEMIS descending into the ocean through the culvert. (photo: Peter Kimball)

The ARTEMIS headlight gives the culvert and drill hole a “stargate” appearance. (photo: Peter Kimball)

Reporting by Peter Kimball

ARTEMIS in the Water

ARTEMIS sits fully submerged in the drill hole. The culvert liner glows in the dive lights used to check the vehicle orientation and mechanical clearance. (photo: Peter Kimball)

Yesterday (Monday), we submerged ARTEMIS in the Ross Sea for the first time. This is a huge milestone for us, but also one that we hope will feel insignificant soon as we progress to more ambitious operations.

The day started with priming of the pumped water instruments and sampling lines. These need to be filled with seawater (and emptied of air) before ARTEMIS can go in the water for buoyancy adjustment. The science team used a Niskin Bottle sampler to bring up seawater from beneath the culvert for this purpose. Meanwhile, the software and mechanical teams prepared the vehicle for submersion.

The actual dunking process was slow as we were very careful about mechanical interference between the robot and the culvert. We were able to fully submerge ARTEMIS and record its weight in water using a calibrated dial spring scale from Crary lab supply. This was the first step in the critical process of ballasting ARTEMIS to sit at near neutral buoyancy in the water of the Ross Sea.

From McMurdo and from our field site, the sun crosses over Mt. Discovery (or behind just two weeks ago!) at about midnight. The weather was a little nasty yesterday, but easing as we finally left the field site a little after 11 pm. The low sun and easing weather provided an epic view to the South as we headed home for the night.

Nighttime sun glints off of continental ice beyond Mt. Discovery. (photo: Peter Kimball)

Reporting by Peter Kimball