While Japan is gearing up to send a miniature humanoid robot to the International Space Station, the DFKI Robotics Innovation Center and the ZARM (Center of Applied Space Technology and Microgravity) are working on a pair of robots that may one day help explore craters on the Moon in search of water ice. The RIMRES (Reconfigurable Integrated Multi Robot Exploration System) project combines a six-legged robot that can be picked up and moved with a faster wheeled transporter
The SHERPA rover, a 2.4-meter (7.8-foot) long, 200-kg (440-pound) transporter moves using a hybrid wheel-leg system with adaptive suspension. It is therefore able to quickly move over bumpy terrain on its wheels, but can lift each of its four legs independently to climb over boulders or free itself should it become stuck. Its primary duty is to transport a scout robot to and from lunar craters, which it can lift and carry under its belly or with a 1.8-meter (5.9-foot) long arm.
The CREX (Crater Explorer) hexapod measures one meter (3.2 feet) in length and weighs just 27 kg (60 pounds). It's much too small and slow to get around the lunar expanse on its own, which is why it relies on SHERPA to get from place to place. Each leg has four joints and multiple sensors which help it walk on uneven terrain, allowing it to negotiate the steep slopes of a crater's rim. During transportation, it curls its legs up into a neat and tidy package to stay out of the way.
The RIMRES project builds on an earlier project called SpaceClimber, which ran from 2007-2010. That robot was a hexapod similar to CREX that could handle slopes up to 80 degrees and was semi-autonomous, capable of finding its way using built-in sensors. Of course, it will likely be years before these robots make the trip to the Moon, but for now they give us an enticing glimpse into what future space missions may look like.