Alien Ocean Probe Practices in Mexico

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May 18, 2007 — A sinkhole in Mexico seems an unlikely spot to prepare for a search for extraterrestrial life, but that's exactly where a team of scientists and engineers have gathered this week to test a NASA robotic probe that may one day dive into an ocean on another world.

The sinkhole itself is far from ordinary. It could swallow the 1,046-foot tall Chrysler Building with room to spare, though nobody yet knows the chasm's true depth.

That's one goal of the expedition to El Zacatón, located in central Mexican state of Tamaulipas.

Some scientists suspect the vertical cave, or cenote, could be deep enough to hold a stack of three Chrysler Buildings.

Another objective is to study the geothermal vents that feed the 328-foot wide sinkhole and find any life forms that may be down there.

The expedition will be the most ambitious test in NASA's Deep Phreatic Thermal Explorer, or DEPTHX, program. Researchers are using an unmanned automated submersible that can navigate without tethers in confined and complicated underwater environments.

The probe, which was built by Texas-based Stone Aerospace under a $5 million NASA grant, was lowered into the sinkhole on Tuesday.

Once scientists are sure all the instruments are working properly, the probe will have about six days to make three-dimensional sonar maps of the cave and collect samples for life science experiments.

"It's an ambitious program, but the vehicle performed well in two earlier field tests," said David Wettergreen with Carnegie Mellon University, which developed software for the probe's navigation systems.

If all goes well, the next test of the robot is expected to take place in Antarctica's Lake Bonney, where conditions are much more similar to the ice-capped environment of Europa, a moon of Jupiter's that is believed to hold an underground ocean.

Europa is a leading candidate for hosting possible extraterrestrial life in the solar system.

"Because of the well-supported presence of water ice on Europa and the probability that there are briny oceans, Europa has to be a major target for the search for life in the solar system," said Jere Lipps, a University of California, Berkeley integrative biology professor.

"In Antarctica, every phylum of algae, protozoan, bacteria and animal lives in the ice, many of them in brine channels that don't freeze," Lipps said. "Life thrives in ice, it doesn't mind at all."

Before leaving Mexico, DEPTHX also will explore two nearby cenotes, Caracol and Verde, during the planned two-week expedition.