NASA Robot to Explore 'Bottomless' Pit

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

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

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

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

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

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

Software written by Carnegie Mellon University's Robotics Institute will allow the untethered sub to navigate in the sometimes closely confined underwater spaces and probe the pitch-black sinkhole with 56 sonar sensors for mapping.

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

DEPTHX also will be used to explore two other sinkholes, Caracol and Verde, during the team's two-week expedition.

• Video: DEPTHX in Action
• Sinkholes: New Study Digs for Deeper Understanding
• Image Gallery: Robot Explorers