Update, 4/14/14: The SpaceX launch that was supposed to bring Robonaut 2 its legs has been postponed. The Falcon 9 rocket has a helium leak, NASA tweeted. R2 responded to the news on Twitter:
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The International Space Station's humanoid robot is getting a pair of legs. The fresh gams are scheduled to go up to space today aboard a SpaceX-operated resupply mission.
Before this, Robonaut 2—the first humanoid robot in space—did not have legs. It was just a torso mounted on a short post. The new limbs will give R2 a decidedly spidery nine-foot "leg span." The legs are also a bit more flexible than most humans'. They have seven joints each, plus pincer-like feet that are able to grip handrails and sockets inside and outside the space station. The feet even have small cameras to help them identify grips. So now R2 will be able to move around the space station and work with both hands while keeping itself in place in microgravity using its feet.
Researchers are developing Robonauts to perform repetitive or dangerous tasks aboard the space station, so human astronauts don't have to. Humans can tele-operate the robot or program it to do some things autonomously. Kind of like an intern, however, R2 is both working and learning at the same time. Since it first flew to space in 2011, it hasn't done a lot of helpful tasks. Instead, it's undergone a number of experiments checking its ability to push buttons, flip switches, and use tools that people normally operate. In 2012, NASA announced R2 did its first helpful bit of work, checking air flow in the ship. It's also used the station's RFID inventory scanner.