NASA learns from Star Wars in building ‘floating droid’ Sometimes truth is stranger than fiction. And sometimes the two are one and the same. Take NASA’s Personal Satellite Assistant (PSA). Designed to aid astronauts in orbit, the PSA looks like something inspired by the movie Star Wars. The reason? It was. What is a PSA? Strictly speaking, it’s a softball-sized self-propelled robot designed to work in microgravity. The idea is that the PSA will float inside the Space Shuttle, International Space Station, or even onboard an upcoming Mars mission. While the astronauts are busy with more important tasks, the PSA will keep an eye out for pressure leaks, toxic gases, temperature drops, or a dozen other hazards that, although subtle, could kill everyone aboard.