'Mushroom' robot to plumb the depths

After a successful deep-water test in Mexico, a NASA-funded autonomous robot is a step closer to proving its ability to carry out a mission to seek life on Europa, an ice-covered moon of Jupiter.

The robot, the Deep Phreatic Thermal Explorer (DEPTHX), which resembles a 2.5m-wide, 1.2-tonne orange mushroom, has the tools and intelligence to swim to the depths of flooded caverns, create maps of the area, then bring back scientific samples. Carnegie Mellon University developed the software that guided it.

The robot's test involved exploring La Pilita, a 115m-deep sinkhole in eastern Mexico. In the next challenge, planned for May, it is expected to descend hundreds of metres into a dark, unexplored region of Mexico's El Zacaton, the world's deepest sinkhole.

DEPTHX is built to find its own way around an underwater cave without tethers, guidance or outside communication.

That autonomy is what distinguishes the robot from remotely operated vehicles such as the Alvin submersible, which was used in the search for Titanic.

Autonomous navigation is only half of DEPTHX's mission, however. The robot will also have the ability to identify targets of scientific interest and bring them back alive.

It can check the salinity, acidity, conductivity and chemical content of the water and follow the scent to a hydrothermal vent or a microbial mat. The robot will even be able to look for colour variations that signal the presence of organisms. It can then extend a mechanical arm, grab a sample and bring it to the surface.