Tim Furniss/LONDON

NASA IS STUDYING the possibility of bringing forward a mission designed to bring back samples from Mars, following public excitement raised by its announcement that microscopic life forms may once have existed on the planet. The original launch date was scheduled for 2005.

The evidence of life, which NASA admits is still highly speculative, is based on analysis of a 1.9kg meteorite, which landed on the Earth 13,000 years ago and which "-may have" originated from Mars as a result of a cometary collision with the Red Planet 15 million years ago. The rock matches the unique Martian chemistry measured by the NASA Viking Mars landers in 1976.

Analysis of the meteorite revealed organic molecules called polycyclic aromatic hydrocarbons which "-can be associated with life processes", says NASA. Scientists found shapes that "resemble" some forms of tiny fossilised bacteria. NASA says that "-we don't claim to have conclusively proven" to have found life.

"We may need to accelerate some areas, such as the technology to return samples to the Earth," says NASA administrator Daniel Goldin. The agency also emphasises that "-a sample return mission will depend most on technologies that may not exist, or are still in the making".

The budget could also be a major hurdle, but Goldin says that he is not asking for a major programme, "just a systematic process" of missions.

The "life on Mars" hysteria, followed what was planned originally, to be a low-key announcement in an academic journal of speculative research.

Astronomer Carl Sagan says that "-this is not evidence of life" and John Kerridge, a planetary scientist at the University of California, says that "-the conclusion is premature-there are non-biological processes which could have produced the phenomena".

Source: Flight International