A robot wheels across a rocky, windswept landscape that looks like the surface of some distant planet from a science fiction film. But it is not in outer space, it’s on the slopes of Europe’s most active volcano. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany’s space program. The program has enlisted experts from Germany, Britain, the United States and Italy to research ROBEX (Robotic Exploration of Extreme Environments) with the aim of improving robotic equipment that will be used in space.