Space scientists send probe to Titan

Space scientists are sending a small package to Titan, one of the moons of Saturn. The package in question is a space probe called Huygens which is due to be separated from its mother ship, Cassini, after being locked together for seven years and two billion miles.

Explosive bolts are timed to release Huygens in the early hours of Christmas morning as it comes within range of Saturn. It will then continue to coast unguided and unpowered for 20 more days before reaching its final destination - Titan.

If all goes to plan, Huygens will arrive at Titan on 14 January and, in a carefully choreographed sequence of events, will parachute slowly through the moon's thick atmosphere.

The probe is programmed to collect copious quantities of data as it descends through the atmosphere but whether it survives the impact depends largely on whether it lands on hard ground, an "ocean" of liquid hydrocarbons or something in between - a sticky coating of tar.

Scientists involved in the project said that the Huygens probe could land with "a thud, a squelch or a splash" depending on what is covering Titan, which is shrouded in such a thick atmosphere that its surface has never been clearly observed.

Professor Carl Murray of Queen Mary college, University of London, said that Titan is one of the most mysterious places known to planetary astronomers and might well turn out to be completely unique in the Solar System.

"There's no other natural satellite in the Solar System with such a dense atmosphere and we know the surface is unusual because there is some sort of constant resurfacing going on that we don't know about. It really is an enigma," Professor Murray said.

If the separation does not go to plan, scientists at the European Space Agency have a further nine days to correct the problem before the entire mission - including Cassini's scheduled four-year orbit of Saturn - has to be abandoned.

Titan has fascinated astronomers because its thick, nitrogen-containing atmosphere is rich in organic compounds and so is considered similar to the conditions that existed on Earth when life first evolved more than 3.5 billion years ago.

However, there is little expectation of finding life on Titan, where the temperature is minus 180C.

- THE INDEPENDENT