Robots team up to explore planetary lava caves

In the not-too-distant future, the search for signs of life on Mars and the moon could see the next generation of robots exploring a new frontier: subsurface lava tubes. These missions could also help us determine the best locations for establishing human bases.

To see whether this could be feasible, scientists tested three autonomous robots in a lava cave on the Spanish island of Lanzarote.

Lava tubes are deep underground caves formed by volcanic activity and are found in various parts of the world, as well as on Mars and the moon. These cavernous spaces could offer protection from the harsh environment of space, such as extreme temperatures, radiation and bombardment from meteorites. This means they may not only harbor existing life but could also serve as ideal locations for manned lunar and Martian bases.

Human exploration of these tubes is risky, expensive and currently unfeasible. Robots are a safer, more cost-effective option. “A heterogeneous cooperative robot team is a promising approach to address the access and exploration of extraterrestrial lava caves,” wrote the researchers in a paper published in Science Robotics that describes their work on Lanzarote.

Cooperative robots

Over a period of 21 days, field tests were conducted in a real lava cave environment and divided into four phases. First, two rovers mapped the surface around the entrance to the underground cave. Then one of the rovers launched a sensorized payload cube into the opening to create a detailed 3D map of the entrance.

The next and most challenging step involved two robots working autonomously together. The smaller rover attached itself to the larger one and started rappelling down the cave. Then it detached itself and moved 235 meters into the cave, creating a 3D map as it traveled.

Next steps

While the tests were successful, several challenges need to be addressed before robots can explore lunar or Martian tubes or caves. For instance, the ground-penetrating radar’s performance was reduced by moisture in the test environment, and there were some mapping limitations due to sensor interference and a lack of ground-truth data. Additionally, achieving full autonomous navigation within a cave remains a significant hurdle.

But despite these limitations, the research brings us one step closer to being able to scout for locations away from Earth where humans could one day live. The technology could also help us in our long-standing quest to find out whether or not we are alone in our solar system.

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