INTO THE SHADOWS
Life on other planets is likely to be found underground, where there is shelter from radiation
In the past, landers on both the Moon and Mars have stayed near the equator, where there’s plenty of sunlight for their solar panels. Now, however, attention has moved to the darker shadows of our closest neighbours. The lunar south pole has craters where the Sun never reaches the bottom, potentially allowing for water ice to survive, while Martian cave systems could shelter microorganisms from damaging radiation. These craters and caves might one day serve as foundations for a permanent human base.
Exploring these new terrains requires a new type of vehicle, as the rovers that have so far traversed the Moon and Mars are ill-suited to a cave’s rugged terrain. Robots with legs have been suggested since the early days of the Space Age, but are only now becoming technologically feasible. In fact, the first lunar ‘scuttler’ robot, the spider-like Asagumo from UK-based company Spacebit, is due to take its first steps on the lunar surface within the next year.
Meanwhile, the BRAILLE team (Biological and Resource Analog Investigations in Low Light Environments) at NASA’s Jet Propulsion Laboratory are developing the tools such a robo-explorer will need. The bots will need to be autonomous, because the potential of losing communications, not to mention the minute-long lag time between Earth and Mars, makes direct human control impossible. The team use NeBula autonomy software that allows a robot to explore environments and adapt to unexpected scenarios without the need for human oversight.
BRAILLE simulated a mission at the Lava Beds National Monument in California, using the software on a pack of Boston Dynamics SPOT robots. The first robot was armed with LiDAR to map out the complex tunnels and identify interesting targets. A second explorer took a closer look at these, even swabbing samples from the walls. A third SPOT remotely analysed the chemical makeup of the targets. During the test, the trio climbed up rough surfaces that would stop a traditional rover in its tracks, and navigated narrow passages that even a human might struggle with.
But even these nimble explorers could be stumped by deeper crevasses. This is where a NIAC project, ReachBot, could help out. This robot uses extendable boom arms with manipulators on the end to shimmy up and down narrow passageways. Their compactable design means several could be transported together, allowing them to help each other out, pushing against each other to gain leverage. These could be dispatched into tight caves, coming back with samples that would normally be out of reach. It would be easy to carry half a dozen on the backs of Spacebit or BRAILLE descendants, ready to explore every nook and cranny of the rocky surfaces of our Solar System.