In August 2012, Voyager 1 made history as it entered interstellar space, the region between stars, filled with material ejected by other stars that died millions of years ago. Voyager 1 and 2 are the only spacecraft ever to operate outside of the heliosphere, the region of space affected by the sun 's constant flow of material.

Nasa scientists are celebrating as, after a period of silence, the craft recently called home again using a bit of kit that it hasn't used for more than forty years.

The 47-year-old NASA Voyager 1 fell back on a radio transmitter it hadn’t used since 1981 to ping home base after a technical issue caused a days-long communication stall between Earth and the farthest-ever recorded spacecraft.