Two Billion Miles, Seven Years, GBP 250 Million – Now Titan is Finally Giving Up Its Secrets

ASTONISHING pictures of an alien world were being examined by ecstatic scientists last night as a European spacecraft touched down on the surface of Saturn’s largest moon, Titan.

After travelling more than two billion miles and taking roughly seven years to get there, the Huygens space probe made a successful landing, parachuting through the thick, smoggy atmosphere to reach the surface at about 11:30am.

Nervous scientists had to wait hours until, just after 8pm, the first images began to come through. Rivers hundreds of metres across running into a sea of a liquid that could be like lighter fuel, boulders and what appeared to be large blocks of ice were all captured in the grainy, black and white pictures.

Marty Tomasko, of the Lunar and Planetary Laboratory at the University of Arizona, in Tucson, which made the probe’s camera, said: “There aren’t too many planets with liquid. There’s Earth, and now there’s Titan.”

It is thought the successful completion of what has been termed “the most ambitious unmanned space mission of all time” – run by the European Space Agency with significant contributions from British scientists – could herald a new era of space exploration.

One of the most striking pictures, taken from an altitude of ten miles, showed a complex system of what looked like river channels and tributaries running into a delta. On the right of the picture was a mysterious dark area which hinted at a possible shoreline and lake or sea. Scientists had speculated that there might be lakes or even oceans of liquid methane or ethane on the surface of Titan.

Dr Simon Green, one of the scientific team from the Open University, said: “They are river-sized, not merely little trickles – probably hundreds of metres across.”

Scientists said the channels were either caused by falling rain or seepage of liquid hydrocarbons – similar to lighter fuel or natural gas – which had soaked into the ground.

Another Open University scientist, Professor John Zarnecki, in charge of Huygens’s Surface Science Package – a collection of instruments designed to probe the surface of Titan – said the craft had sent back three hours, 37 minutes and 26 seconds of data. Seventy minutes of this was transmitted from the surface.

Speaking from the European Space Agency’s operations centre at Darmstadt, Germany, he said: “The probe is absolutely rock solid, there’s no motion at all. It’s pretty clear that we’re not sitting on a liquid. What we’re sitting on we don’t know. It’s solid, but it’s not very solid.”

Another image, taken some five miles above the surface, showed light and dark masses, indicating there was varied terrain. A third image taken on the surface showed several large white chunks – boulders or blocks of water ice – in the foreground and a stretch of grey surface behind them.

Professor David Southwood, director of science at ESA, said: “I am delighted. I just wanted to know that there was complexity down there, that this really was a world that was going to yield totally new science.

“For me, it’s the end of a wonderful day. I’m going to remember it for the rest of my life.”

British scientists and engineers played key roles in the GBP 250 million Huygens mission. The probe’s flight software and parachute systems were designed by British companies, and UK scientists supplied some of the craft’s most vital instruments.

As well as taking pictures of Titan, Huygens will also listen to sounds from the surface – the first time noises will ever have been heard on another planetary body.

In many ways Titan, which is the only moon in the solar system with an atmosphere, composed of nitrogen, methane and ammonia, resembles the Earth before the birth of life four billion years ago. Scientists believe it will act as the perfect laboratory for studying the early Earth.

However, finding Earth-type life on Titan is unlikely with temperatures of minus 180C, although one group of scientists claims conditions on the moon could support specially adapted life forms.

Earlier, scientists gathered at the Royal Society in London where a live link was set up with Darmstadt, broke open bottles of champagne in celebration.

Among them was Professor Colin Pillinger, chief planetary scientist at the Open University, who led Britain’s ill-fated Beagle II mission to Mars, which ended when the spacecraft crashed on Christmas Day 2003.

Prof Pillinger said: “It would have been the end of the world if we hadn’t got this one down. There’s now no doubt that ESA’s confidence will be restored in landings.”

Huygens was carried to Saturn by NASA’s Cassini spacecraft. After its launch on 15 October 1997, Cassini followed a complex route, picking up speed by swinging past Venus (twice), the Earth and Jupiter to obtain an extra “kick” from each planet’s gravity.

It reached Saturn on 1 July and Huygens separated from its mothership on Christmas Day then navigated itself to Titan using autonomous guidance systems developed in Britain.

“I think all of us continue to be amazed as we watch our solar system unveil,” NASA science administrator Alphonso Diaz said in Darmstadt.

Titan was the first of Saturn’s 33 moons to be discovered, in 1655 by the Dutch physicist and astronomer Christian Huygens.

After Jupiter’s Ganymede, Titan is the second-largest moon in our solar system, bigger than the planets Mercury and Pluto.