NASA probes sinkhole as proxy for icy moon

NASA is testing an underwater robot in one of Earth's deepest sinkholes in a first step toward searching for life on Jupiter's icy moon, Europa.

El Zacaton, near the Gulf coast of northeastern Mexico, is about 100 metres (328 feet) wide and more than 1,000 metres (3,280 feet) deep. It could easily hold the Eiffel Tower.

Scientists plan to map and take samples in the dark, water-filled fissure with the 1.5 tonne DEPTHX robot over the next two weeks as a prelude to the proposed navigation of Europa's ice-capped oceans in about 20 years.

The mission is the latest step in a 400-year-old endeavor to understand Jupiter and its distant moons.

"We're so sure there's water on Europa that the real question is whether there is also life, whether there's something in the ocean that bugs can eat," said Chris McKay of the NASA Ames Research Center in California.

"This robot is the ideal way to search," he said.

Lowered by a 60-tonne crane, the battery-powered robot, nicknamed "Clementine" for its round shape and orange color, will make daily descents into the vertical cave known in Mexico as a cenote.