The humanoid robots have been built to look like people, and have five fingers on each hand just like people do. This allows them to imitate the signals given by American football referees.
Dressed in a referee's hat and whistle, the robot showed off its repertoire, including the all-important touchdown.
R2 was designed for work on the International Space Station (ISS), and arrived there for its first mission in 2011. Because it has hands and fingers like a human, it can use many of the same tools as an astronaut.
The robot "sees" with cameras in its head. It can be either remote controlled by an operator, or work independently thanks to software which allows the robot "think" for itself and carry out a simple task.