IT is not just on Earth that drones have uses (see article). Three experimental ones, 22cm across and known as Synchronised Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES (even though they are actually truncated rhombic dodecahedrons), have been buzzing around the International Space Station since 2006 (see picture above). Now, a new and more advanced version, the Astrobee, is being designed at the Ames Research Centre, a NASA laboratory in Mountain View, California.
The Astrobee, which is scheduled for deployment in 2017, eschews geometric complication: it is a simple, 30cm cube. But it is otherwise a more complex beast than its predecessors. SPHERES can be used only in a designated area of the station, and they rely on beacons to know where they are. The Astrobee, by contrast, will use computer vision to orient itself and to navigate around.