Robonaut2 has 42 degrees of freedom and is highly dexterous, says Ambrose. "We added more range of motion by giving it an opposable thumb and making the manipulators much faster," he says. The robot also has two standard and two high-definition cameras embedded inside the gold helmet that covers its head. This provides stereoscopic, 3-D images of its surroundings, which the robot uses to build a depth map of objects nearby. It also has a number of indicator lights that give astronauts a general understanding of what state the robot is in. And the robot can sense very light contact; if a person touches it anywhere it can stop instantly, to protect them from harm. Its outer skin is also made of soft, smooth materials so that if an astronaut does bump into it, she will not be harmed.

The new robot is designed to work autonomously, using feedback from sensors to complete set tasks. "In addition to building new robotic hardware, one of the main challenges is writing software to make robots smart enough to do things by themselves," says Andrew Ng, a professor of computer science at Stanford University, who works on developing general-purpose household robots.

Ambrose says that NASA wants to use the robot for a number of different missions, including trips to the space station to conduct repair work, and missions to the moon or Mars as a precursor mission to manned ones. When it's part of a human-robot team, the robot could even be left behind to continue scientific work. But Mason adds that the robot is still very young, and there is lots of work to be done. "Human performance is a high bar, and while robots have not come close to it, every advance of this kind is very important," he says.