NASA Robot to Explore 'Bottomless' Pit

A robotic yellowsubmarine will journey this week to the world's deepest sinkhole, which alreadyhas taken the life of one diver who sought to reach its bottom and discover thelife that might exist there.

Others havetried to reach the end of this seemingly bottomless pit in the Mexican state of Tamaulipas, known to be at least 925 feetdeep, but no one has ever succeeded.

The self-automated"DEPTHX"(Deep Phreatic Thermal Explorer) will search the depths of the El Zacatoncenote, or geothermal sinkhole, for life and also study its dimensions and lookfor the vents that feed it.

NASA, whichfunded the robotic explorer, views the mission as a test-run for a potential journeyto Europa, a moon of Jupiter thought to contain liquid water beneath miles ofice--and possibly complex forms of life. New technologies that could helpexplore its ocean will be put to the test during the robot's descent.

"We'llspend the first two days checking out DEPTHX's sensors, updating its softwareand performing a test dive to 250 meters [820 feet] to check its pressurehousings," said David Wettergreen, who helped create the 8-foot-long submarine.

Once the vesselpasses it final exams, Wettergreen and his team will have six days to probe thesinkhole's watery depths. "It's an ambitious program," Wettergreen said, "butthe vehicle performed well in two earlier field tests at the La Pilita cenote,"another Mexican sinkhole.

Softwarewritten by Carnegie Mellon University's Robotics Institute will allow theuntethered sub to navigate in the sometimes closely confined underwater spacesand probe the pitch-black sinkhole with 56 sonar sensors for mapping.

Theprogress of DEPTHX, as it gathers water and stone samples from the cenote'swalls, can be monitored at the mission's Web site starting today.

DEPTHX alsowill be used to explore two othersinkholes, Caracol and Verde, during the team's two-week expedition.

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