See below for a video from the test, and click here for a photo gallery.

Ace spelunker/space-hopeful Bill Stone, profiled in PopSci´s February issue, completed the initial field test of DepthX, his autonomous underwater robot, this week in the state of Tamaulipas, Mexico. If you´ve read the
target=”_blank”>article, you´ll know that the idea is to work the kinks out of this ´bot so that it might later become a model for systems that could be used to explore one of Jupiter´s moons, Europa, which is covered in ice but believed to be home to a subterranean sea.

After a bit of drama at the border (they were hauling a giant ovoid robot in a flatbed truck, after all), Stone´s team arrived in Mexico and camped out at Rancho la Azufroza, where they spent several days assembling the robot and testing DepthX´s sighting and maneuvering capabilities in an underwater cave called La Pilita.

The ´bot plunged to a depth of about 300 feet, captured images here and video [see below], and built a 3-D map of the cenote while the team tracked its functions remotely, from an above-ground computer screen. They collected data and some samples from the floor of the cave and confirmed that everything was in working order-overall, a grand success. [Read a complete account of the trip on Stone´s blog, target=”_blank”>here.

Next month we´ll cover part two of the testing mission, and then in May, the most ambitious expedition, in which DepthX will attempt to autonomously navigate to a depth of more than 1,000 feet in Zacaton, the world´s deepest sinkhole. View a slideshow of images from the most recent mission here, and watch a video of the adventure below.

Still Water Running Deep

The source of El Nacimiento (â€The Springâ€) lies just 100 meters west of the main field lab at Zacaton. The horizontal black slot at center is the entrance to the Pasaje de la Tortuga Muerta (â€Dead Turtle Passageâ€), which leads upstream and underground to the main Zacaton cenote. It was first explored in 1989 by Jim Bowden and Gary Walton and leads 220 meters underground, re-emerging at the southwest corner of Zacaton.

Tough Transport

Marcus Gary ably drives the ‘bot to cenote La Pilita, a four-wheel-drive journey of about a kilometer, successfully completed in about 30 minutes.

With Eye Wide Open…

The eye of the ‘bot-wide field camera on the Science Payload for DepthX.

Powering Up

After unpacking most of the hardware into the field lab the previous day, the first order of business was to top off the charge on the twin litihium-ion power stacks used to run DepthX.

Including Batteries

John Kerr carefully loading Battery Pod 1 into DepthX. Each of the two Lithium-Ion-battery stacks contains the energy equivalent of 6 pounds of TNT.

The Hard-Earned Sample

This small pile of soft sediment was collected at a depth of 50 meters in the cenote La Pilita 40 meters under the cave edge. It was collected by the solid-core sample device on the end of the sample arm.

Uncrating the ‘Bot

First order of business was to uncrate it. At 1.5 metric tons, DepthX is an industrial-strength machine (rated to an ocean depth of 1,000 m), and it means it´s not something you toss about by hand. Alejandro Davila, the owner of Rancho la Azufrosa, kindly made arrangements with a local Tampico-based crane company to ship a mobile handler to the site. We then began unloading all the electronics modules into the field lab for individual checkout.

… and Arm Outstretched

A view from above the DepthX robot, the sampling arm extendeed to test the operation of the solid-core sample device. The coring devise is the gray cylinder at the front of the probe.

Into the Deep

John Kerr releases the vehicle to begin testing.

The Land of Nacho

Nacho, the main ranch hand at Rancho la Azufrosa, brings over one of many loads of sand used to level out the ‒bot garage,†so sheets of plywood could be laid down to serve as a surface for maneuvering the bot. The lower portion of its orange frame rides on four heavy shop casters, but these need a flat surface to work on.

Crystal Chips

Biogenic mineral crystal from the walls of La Pilita fell into the frame of the DepthX robot during a deep mission. These crystals are thought to be forming through biologic-mediated processes.

‘Bot Chilling

Nathaniel Fairfield gets to experience the world of the ‘bot (at shallow depth).

Seeing in the Dark

DepthX begins autonomous mission after dark. The ‘bot made a powered descent to 80 meters and successfully conducted exploration circuits at three depth levels.

Cave Critter

A four-inch purple scorpion was found on the trail walking back from La Pilita. These scorpions are common in the caves nearby.