The Voyager mission has not lacked for highlights, having beamed back the first glimpses of methane oceans, erupting volcanos on a Jovian moon and a thunderstorm on Saturn. But Prof Ed Stone, who has been at Voyager’s scientific helm since 1972, says there is one place above all that he longs to visit again.

The veteran space scientist is calling for a return mission to Saturn’s icy moon, Enceladus, whose underground oceans are widely viewed as the most promising place in the solar system in which to hunt for extraterrestrial life.

“We really need to get back and look at that moon,” said Stone, 83, a professor of physics at the California Institute of Technology. “We know there’s water ice evaporating – geysering – from its south pole. It’s snowing all the time. That means there’s liquid water beneath the icy crust. Here on Earth, wherever there’s water there’s microbial life.”