Meet the explorer that could be 1st to search for life in Martian caves

An artist's concept shows ReachBot using its extendable arms to explore a Martian cave.

(CNN)Exploring beneath the surface of other planets may be the key to determining whether life has ever existed outside of Earth.

As other missions, including that of NASA's InSight lander, have shown, drilling down through the surface of planets like Mars is tough -- a little too tough to get more than a few inches into the subsurface.
Recently, the Curiosity rover measured total organic carbon, a necessary ingredient in the molecules of life, in Martian rocks for the first time. But it doesn't prove that life ever existed on Mars, because carbon can also be produced by nonliving sources.
    New research suggests that the best chance of finding past or present evidence of life on Mars requires going below its surface -- at least 6.6 feet (2 meters) below. Mars has an incredibly thin atmosphere, which means that the surface of the red planet is bombarded by high energy radiation from space, and that could quickly degrade substances like amino acids that provide fragile evidence of life.
      Those harsh surface conditions also present a challenge for astronauts, which is one reason scientists have suggested that caves on other planets could be the key to future exploration. Vast cave systems on the moon and Mars could act as shelters for future space travelers.
      Caves could also contain resources like water, reveal more about the history of a planet -- and be havens for evidence of microbial life. On Earth, there are a varied range of cave systems, many of which remain unexplored, and they support diverse groups of microorganisms. But caves are dangerous -- and since we've never peered inside a Martian cave, it's difficult to know what to expect.
      Before humans land on Mars and explore its subsurface, a group of scientists want to send ReachBot -- a robot designed to crawl and climb through extraterrestrial caves.

        A spelunking robot

        The idea for ReachBot was born in 2018 when Marco Pavone, director of the Autonomous Systems Lab at Stanford University, and his students were brainstorming concepts for a Martian cave explorer.
        They knew the robot would need to be able to grab anchor points so it could move without falling -- and if it couldn't find enough anchor points, it wouldn't get very far.
        One of his students suggested the idea of a small robot with extendable arms that reach out like measuring tape, which could be used the same way Spider-Man slings webs to help him navigate the skyline of New York City.
        The robot concept is between the size of a basketball and a toaster oven and covered in extendable booms equipped with spiny grippers that could grab objects and grasp or push off the steep, rocky surfaces of Martian caves. It would be able to anchor itself and crawl across long distances.
        When the robot's booms aren't needed, they roll up to stay out of the way.
        Pavone, who is also associate professor of aeronautics and astronautics at Stanford University's School of Engineering, and his students arrived at the idea of a robot with extendable booms. They created a proposal to submit to NASA's Innovative Advanced Concepts Program, which funds visionary concepts in the field of space robotics that could transform future missions.