2007-04-19 | SCIENCE
Antarctic Lake Robot Probe Sets Sights on Outer Space

A robotic probe designed to draw an underwater three-dimensional map showing the biological and geochemical composition of an ice-bound Antarctica lake may prove to be the ideal tool to search for life on other planets or moons where ice is known to exist.

Peter Doran, associate professor of earth and environmental sciences at the University of Illinois at Chicago, is the lead investigator in a three-year, $2.3 million dollar study funded by NASA to build the probe that will map Antarctica's West Lake Bonney, a two-and-a-half mile long, one-mile wide, 130 foot-deep lake located in the continent's McMurdo Dry Valleys. Bonney lies perpetually trapped beneath 12 to 15 feet of ice.

"Our goal is to build a submersible autonomous underwater vehicle to map in 3-D the geochemistry and biology of this ice-covered lake," said Doran, who is also a principal investigator on the National Science Foundation's Long-Term Ecological Research project in the McMurdo Dry Valleys. NASA is interested in the project because a modified version of the vehicle may be used to probe beneath subglacial ice and look for signs of life, past or present, on Mars or on moons such as Jupiter's Europa, which essentially is an ice-covered ocean. "The robot will swim under the ice un-tethered," Doran explained. "It will have a sensor package that will lower down on a cable as it moves under the ice. It will do a grid pattern, stop, and lower the sensor package down through the whole water column to build up a 3-D data set. It will also have a camera to take various images." The probe is called ENDURANCE -- an acronym for Environmentally Non-Disturbing Under-ice Robotic ANtarctic Explorer. It is a modified version of a device called DEPTHX -- Deep Phreatic Thermal Explorer -- developed by Austin, Texas inventor William Stone, a co-investigator on the ENDURANCE project. Stone is using DEPTHX to explore underwater caves in Mexico as part of NASA's Astrobiology, Science and Technology for Exploring Planets program. Once that is complete, DEPTHX will be reengineered to become ENDURANCE, then tested next February in an ice-covered Wisconsin lake before making the trip to Antarctica in November. ENDURANCE will map Bonney for a month, then do a second mapping in 2009. Data gathered will be relayed back to Chicago where it will be used by UIC's Electronic Visualization Laboratory to generate various 3-D images, maps and data renderings of the lake. "The potential scientific windfall is huge," Doran predicted. "We'll see lakes like we've never seen them before." ENDURANCE is about four feet tall and three feet wide. It will be decontaminated and sterilized before being lowered through the ice hole into the lake. Because it will gently float around the top water layer and will slowly lower its sensor package into older, denser layers of water below, there is little chance of the water churning and mixing, which could skew the biological and geochemical picture of the lake. If the autonomous vehicle works well, the next goal is sending a much smaller version of ENDURANCE to probe Antarctica's massive, Lake Ontario-sized Lake Vostok, which sits under more than two-and-a-half miles of ice. Some water in Vostok hasn't had contact with the earth's atmosphere in over a million years. "The lessons learned from mapping out Bonney will be important for developing strategies for exploring Vostok and icy moons, like Europa," said Doran. "You're not going to send people there, so you have to develop autonomous ways to do it." Other project co-investigators include Andrew Johnson, associate professor of computer science at UIC; John Priscu, professor of land management and environmental sciences at Montana State University; and Chris McKay and Bin Chin at the NASA Ames Research Center in California. Copyright ©2007, The Board of Trustees of the University of Illinois.

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