Mexican Sinkhole May Lead NASA to Jupiter

By Ceci Connolly
Special to The Washington Post
Monday, May 14, 2007

It may not show up on MapQuest, but NASA scientists are betting that the best route to Jupiter and its ice-crusted moon Europa runs through an underwater cavern in Mexico.

Though the space mission is probably 30 years off, the trek begins in earnest today outside the city of Tampico. A 60-ton crane is scheduled to lower a giant orange robot dubbed "Clementine" into what is believed to be the deepest flooded sinkhole in the world.

For the next two weeks, the fully autonomous robot, which bears an uncanny resemblance to a Volkswagen Beetle, will plumb the previously inaccessible microbial mysteries of the sinkhole -- or "cenote" -- El Zacatón.

Relying on an eclectic team of scuba divers, engineers, biologists and geochemists, NASA is hoping the mission will be the first leg on its journey to Europa.

"We're learning to explore Europa by first exploring a Mexican cenote," said John Rummel, a senior scientist for astrobiology at NASA.

Scientists consider the Jovian moon, with its evidence of liquid water and thermal energy sources, to be "one of the hottest targets for potential life" beyond Earth, said Peter T. Doran, an Earth scientist at the University of Illinois at Chicago who is part of the team.

In the past, if researchers "wanted to explore geologically, we sent a graduate student," Rummel joked. However, even if NASA had a Jupiter shuttle, it would be impossible for those students to take a look around.

"If we walked without a spacesuit onto [Europa] -- at 123 degrees below Celsius and no air -- the radiation would kill us before the lack of air or the cold," he said. "About eight years ago, NASA realized if it was going to effectively explore other worlds, it had to get a lot better about robotic activity."

For NASA, the $5 million, three-year Deep Phreatic Thermal Explorer (Depthx) project is an important test drive of a computerized, underwater vehicle that makes all of its own decisions -- where to swim, which samples to collect and how to get home. Each day, the battery-powered robot will travel deeper into the sinkhole, exploring nooks and crannies that human divers could never reach.

If Clementine performs well, a retooled version will head to Antarctica's Lake Bonney next year. Scientists think the conditions there -- vast thermal waterways below frozen ice -- more closely resemble those of Europa.

In developing Depthx, engineers aimed to build a machine that behaves like a microbiologist, said John R. Spear, an environmental microbiologist at the Colorado School of Mines. "I wanted this robot to be me."

Once the 3,300-pound vehicle, designed by Texas-based Stone Aerospace Inc., is lowered into the sinkhole, it "feels" changes in temperature, "sees" shifts in topography with 56 sonar sensors and "sips" water samples. Those are taken to a laboratory on the surface for further study.

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