Life-hunting space probe Cassini in death plunge to Saturn
IT is a story of life and death. First the space probe Cassini found water on Saturn’s moon Enceladus, indicating life might be hiding there. Now, to protect any possible life, the probe has been sent into a death cycle which will see it burn up in Saturn’s atmosphere to prevent the ageing machine crashing into the moon.
Cassini has begun a series of 22 dives through the 1,500 mile-wide gap between Saturn and its rings, putting it on a planned path to destruction. On its final orbit on September 15, Cassini will plunge into Saturn’s atmosphere, beaming a stream of unique data back to earth as it burns up. Saturn has 62 moons. Nasa has called a halt to the probe’s 12 years of discovery because the propellant tanks are almost empty. The strategy it has chosen will guarantee safe disposal, removing the risk of an unresponsive satellite crashing into and contaminating the planet’s potentially life-supporting moons.
Dr Earl Maize, Nasa’s Cassini programme manager, said: “If Cassini runs out of fuel it would be uncontrolled and the possibility that it could crash-land on the moons of Titan and/or Enceladus are unacceptably high.We could put it into a very long orbit far from Saturn but the science return from that would be nowhere near as good as what we’re about to do.”
Cassini shifted yesterday from an orbit that grazes the outer edge of Sat- urn’s main ring system to a flight path that skims the inner edge and puts it less than 3,000km above the planet’s cloud tops. The probe will make the first gap run on Wednesday, repeating the dive every six-and-a-half days through to its death plunge, scheduled to occur at about 10.45 GMT on September 15. Nasa stunned the world when it announced Cassini had observed huge jets of water vapour and other materials spewing from cracks of Enceladus at its south pole. The jets lead to a vast body of water that may be 30-40km deep in places – and the chemistry in this subterranean ocean could support microbial life.
Cassini scientist Dr Hunter Waite said: “We’re pretty darn sure the internal ocean of Enceladus is habitable and we need to go back and investigate it.”