Researchers at the National Physical Laboratory and the University of Leicester claim to have come up with some sort of GPS system equivalent for space travel, saying they've managed to track things up there to an accuracy of 30km at a distance as far away from us as Neptune.
Their system uses signals picked up by X-ray telescopes from the rhythmic output of pulsars to work out exactly where in the universe a space ship might be, ignoring the inconvenient truth that humanity's most likely to perish here and in a few crappy prefabricated greenhouses on Mars, so such a system's never going to be needed.
Dr John Pye, the manager of Leicester's Space Research Centre, said: "Up until now, the concept of pulsar-based navigation has been seen just as that – a concept. This simulation uses technology in the real world and proves its capabilities for this task. Our X-ray telescope can be feasibly launched into space due to its low weight and small size; indeed, it will be part of a mission to Mercury in 2018. NPL’s timing analysis capability has been developed over many years due to its long heritage in atomic clocks." [University of Leicester]