If Nasa scientists get their way a football-sized space assistant could be floating inside the International Space Station in just three years.

Self-propelled by tiny fans and self-sufficient with solar panels and batteries, it would cruise around the station. Tasks will include checking systems and looking for leaks and the trusty companion is also a mobile computer interface.

Packed with sensors, it would monitor cabin pressure and temperature changes. It could float alongside an astronaut offering advice and acting as a relay to mission control or elsewhere in the space station.

It could also offer translation services for cosmonauts and issue wake-up calls in the morning.

Star Wars

Nasa scientists call it the Personal Satellite Assistant (PSA) and it could be in service in a few years.

It has just completed a design review and is being developed further at Nasa's Ames Research Center in California.

PSA model

According to researchers one of the inspirations for the PSA was Star Wars, the movie, when Luke Skywalker used a self-propelled tiny sphere for target practice with his light sabre.

The main advantage of the PSA is its portability. All of its sensors will be built into the International Space Station but they will be at fixed locations. The PSA will be able to take those sensors wherever they are needed.

Nasa engineers say that a prototype could be evaluated on a Space Shuttle mission in about two years.