In a demonstration of mechanical dexterity, NASA's robot astronaut uses its hand to open a tether hook of the sort that will be used during the upcoming construction of the International Space Station. Designed to be as human-like as possible, Robonaut's hand has four fingers and an opposable thumb. Robonaut is the early prototype for the robotic astronaut being built at the Johnson Space Center in Texas. Intended to accompany astronauts into space, Robonaut will be especially important in emergencies. From the book Robo sapiens: Evolution of a New Species, page 131 top.