Which Humanoid Robot Stands Up Best In Space?
Robert Markowitz/Bill Stafford/NASA/JSC

On spacewalks, one astronaut’s job is sometimes to just hand tools to another astronaut. It’s a simple role but risky, considering that a tiny tear in his spacesuit could rob him of oxygen. This month, NASA will introduce a more durable—and expendable— astronaut when it sends the first android into space: Robonaut 2.

Robonaut, built by NASA and GM, is a head, torso and arms that will be anchored inside the International Space Station. After testing and upgrades, it will graduate to spending time attached to the station’s exterior, where it will be most useful. Astronauts’ bulky gloves make handling tools difficult; Robonaut could hang on to runaway tools and aid with more-complicated tasks. And whereas an astronaut takes at least six hours to prep for a spacewalk, Robonaut could boot up for emergency repairs in minutes.

Recognizing the need for more spacebots, the German Aerospace Center, DLR, has constructed Justin, a robotic torso with similar talents. “There is a friendly competition between us,” says Gerd Hirzinger, DLR’s head of robotics. Germany will probably need to work with other countries to put Justin on a Mars rover or the ISS, but one day the ‘bot could rove on its own spacecraft, repairing satellites. Here’s how the two robots match up.

Round One: Strength
Justin: Even in microgravity, it takes force to move mass. Each of Justin’s carbon-fiber arms can lift 31 pounds
Robonaut: Robonaut can lift just 20 pounds per arm, but that’s enough to shift the ISS’s giant solar batteries

Winner: Justin