British spacecraft approaches Mars landing

A TINY British spacecraft was last night on the verge of solving one of the great mysteries: Is there life on Mars? The Beagle 2 probe will break away soon from Mars Express — the mothership which has given it a six-month piggy-back ride from Earth. The £35million craft will touch down on the surface of the Red Planet on Christmas Day. Equipped with a drill to take samples 15ft down, it will test for life signs and beam the results back to Earth, informs &to=http://www.thesun.co.uk/' target=_blank>THESUN.

&to=http://www.sfgate.com' target=_blank>Sfgate.com reports that As NASA pursues unmanned missions throughout the solar system, the quest for signs of life on distant planets -- more likely in the past than in the present -- is gaining increased attention from space agency planners.

The problems are formidable: They must increase their understanding of how life originated and evolved on Earth; they must deduce the most likely places where water could have existed on planets like Mars; and they must develop new techniques for drilling many yards, and later many miles, beneath the surface of such planets.

Finally, the scientists must be scrupulously careful with every spacecraft and every tool that lands on any planet to make sure they do not carry microbes from Earth that would contaminate whatever extraterrestrial life might conceivably exist now or in the past.

As a result of recent discoveries of microbes living in freezing cold, with no oxygen or light, and the profound pressures of deep underground mines, Jakosky noted, the extreme diversity of life on Earth makes it quite likely that life could be or have been widespread in our solar system. For 30 years, scientists scanning images of Mars from spacecraft have been tantalized by giant channels, broad basins and sinuous valleys on the Martian surface that look exactly as if water had flooded and flowed there billions of years ago.

The mission will fly no earlier than 2010 and could cost as much as $8 billion.

"Proto-cells" then began to form on the warming Earth. And finally by 3.7 billion years ago, the first life appeared along the coasts of small, new continents in the form of "biofilms" and layers of microbial mats whose fossil forms have been discovered in recent years.

Within a few hundred million years, those microbes had learned to use sunlight for energy, growth and reproduction. After a few million years, more advanced life forms emerged. And after that, the pace of evolution and growth of diversity increased swiftly, he noted.

"Understanding the nature and timing of this ascent of life is crucial for discerning our own beginnings," Des Marais said. "This understanding also empowers our search for the origins, evolution and distribution of life elsewhere in our solar system and beyond."