NASA today extended the life of one of its most successful missions to the planets – the exploration of Saturn and its moons. The fantastic voyage of the unmanned Cassini spacecraft, supported by European space scientists, was due to come to an end in July.

But the two-year extension is expected to deliver a stream of new discoveries about the ringed planet as Cassini makes 60 more orbits of Saturn and its family.

Cassini was launched in 1997 but did not reach Saturn until 2004 after a journey of 2.2 billion miles across the solar system. One of its earliest successes was to send a separate probe called Huygens to land on Saturn’s biggest moon, Titan.

UK scientists played a major role in the Titan triumph with Professor John Zarnecki, of the Open University at Milton Keynes, in charge of experiments on the surface.

Titan is the only moon to have a dense atmosphere. Scientists believe its organic chemistry resembles that on a young Earth and that life could be coming into existence in its seas of methane.

Cassini also discovered geysers of water-ice spewing into space from another moon, Enceladus, and helping to stock up the particles in Saturn’s spectacular rings.

Cassini program manager Bob Mitchell, of NASA’s Jet Propulsion Laboratory, in California, said: “The spacecraft is performing exceptionally well and the team is highly motivated, so we’re excited at the prospect of another two years.”

NASA has a history of lengthy planetary missions. A probe called Galileo spent eight years orbiting the biggest planet Jupiter before being deliberately sent crashing into its clouds in September 2003.

And two robot rovers, Spirit and Oportunity, are still trundling about on the surface of Mars after arriving early in 2004 for missions each designed to last 90 days.

Picture: Saturn imaged by Cassini. (NASA)

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