NASA, where a committee is considering using one in an interstellar probe.

ECONOMIST: Rockets are not the only way to travel through outer space

It would be an understatement to say there's been a long build-up to the moment when Voyager 1 ventures into interstellar space: scientists thought the probe was on the edge back in 2010, and we've been waiting for the official milestone ever since.

ENGADGET: AGU study says Voyager 1 has reached interstellar space, but NASA remains skeptical

The Voyager project scientist at Nasa's Jet Propulsion Laboratory, Ed Stone, said he wanted to see a reorientation of the magnetic fields around the probe before declaring it to be in interstellar space.

BBC: Voyager Solar System 'exit' debated