Martian methane probe in trouble

By Mark Peplow | News @ nature.com

Device may be unable to settle debate over indications of life

One of the best chances for solving Mars’s methane mystery may have been lost. The Planetary Fourier Spectrometer (PFS) on board the Mars Express orbiter seems to be broken, perhaps for good.

The instrument’s failure would be a blow for scientists who want to find out how the red planet is producing the methane that has been detected in recent years.

Almost all the methane on Earth comes from some sort of biological source. As a methane molecule typically survives for only a few hundred years in the martian atmosphere, something must have been spewing it out recently, scientists reason. And this has fuelled hopes for discovering life on Mars.

But scientists have recorded very different methane levels with different techniques. In 2004, the PFS found that methane averaged abut 10 parts per billion in Mars’s atmosphere, suggesting that more than 100 tonnes of the gas is released from the surface each year. That same year, Mike Mumma of NASA’s Goddard Space Flight Centre in Maryland spotted levels of 250 parts per billion using a telescope in Hawaii. This week he told an American Astronomical Society meeting in Cambridge that he had spotted levels of 44-63 parts per billion from a different part of the planet.