ENDURANCE – Self Control

The Environmentally Non-Disturbing Under-ice Robotic Antarctic Explorer (ENDURANCE) is an autonomous underwater vehicle designed to swim untethered under ice, creating three-dimensional maps of underwater environments. The probe also will collect data on environmental conditions and take samples of microbial life. Researchers gathered last week in Madison, Wisconsin to test the probe under ice. They plan to test the probe in a permanently frozen lake in Antarctica later this year.

ENDURANCE emerges from its makeshift lab in the University of Wisconsin’s Water Science building.
Photo Credit: Henry Bortman

Astrobiology Magazine’s Henry Bortman reports on the probe’s progress in the field.

Madison, Wisconsin
Field Notes – February 15, 2008

NASA’s ENDURANCE robot today finally made a solo voyage in Lake Mendota’s icy water, albeit a short one.

An electrical problem prevented the robot from moving anywhere on Tuesday, February 12, the first day of testing. That got cleared up on Wednesday, and engineers from Stone Aerospace, the Austin, Texas, company that built the robot, were hoping to send it on an automated voyage to explore the Wisconsin lake on Thursday. But despite working into the night, they were unable to get the robot’s navigation system working reliably. The problem: the lake was too shallow, and the robot’s Doppler velocity logger (DVL) couldn’t get good readings of the lake bottom. This instrument tracks how quickly the robot moves through the water, critical information for automatic navigation.

Friday morning, the robot was reconfigured with the DVL positioned higher on its chassis and pointing straight down instead of at an angle. The change was just a small one, but it was sufficient to allow ENDURANCE to make a few short scripted runs, only a few tens of meters each. On a scripted run, the vehicle performs without human intervention, but it acts according to preset instructions given to it by the engineers.

ENDURANCE is lowered into Lake Mendota on its final day of cold-water testing.
Photo Credit: Henry Bortman

ENDURANCE also remained “tethered” via a fiber optic cable to the computer systems in “mission control,” a conference room in the nearby Limnology building on the University of Wisconsin campus.

On a fully autonomous run, ENDURANCE explores entirely on its own, with no instructions from the engineering team, and no fiber-optic tether attached. Full autonomy wasn’t attempted in Madison.

ENDURANCE will now be packed up for the journey back to Austin, Texas, where the engineering team will continue making both hardware and software improvements in preparation for its upcoming science mission at Lake Bonney in Antarctica later this year.

Read the February 13th field notes.
Read the February 14th field notes.

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