5th November 2013.
On November 5th, The Indian Space Research Organisation (ISRO) successfully launched the Mars Orbiter Mission (MOM). If all goes according to plan, the MOM will reach Mars orbit in September 2013, thus making the ISRO the fourth space agency to send a craft to the red planet. The scientific payload of the craft consists of five instruments, one of which is a Fabry-Perot Etalon sensor to detect the presence of methane in the Martian atmosphere, and to map any potential sources.
Methane was first detected in the atmosphere of Mars in 2003 as large plumes seemingly being emitted from discrete regions. The largest plume was estimated to contain 19000 tonnes of methane. This first measurement was backed up by additional reports of methane using both ground-based and space-based observations.
Various processes could account for the Martian methane, such as hydrothermal or volcanic production (unlikely due to a lack of activity), inputs from comet and meteorite impacts, the actions of microorganisms (should they exist), or production using hydrogen (produced abiotically) via Fischer–Tropsch synthesis (reactions between H2 and CO/CO2 that produce hydrocarbons). Because methane in the atmosphere would be quickly degraded by UV radiation and chemical reactions, its presence implies a continuous source.
However, in September 2013, it was announced that NASA’s Curiosity rover failed to detect substantial methane concentrations on Mars, after analysing six atmospheric samples between October 2012 and June 2013. The suggested upper limit was 1.3 parts per billion. It seems that more research is required to get a definitive answer to the question of whether methane exists on Mars, and how it might be produced. Hopefully the ISRO’s Mars Orbiter Mission will be the next step towards this answer.
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Krasnopolsky, V.A., et al., 2004. Detection of methane in the Martian atmosphere: evidence for life? Icarus, 172, 537-547.
Keppler, F., et al., 2012. Ultraviolet-radiation-induced methane emissions from meteorites and the Martian atmosphere. Nature, 486, 93-96.
Image: Martian sunset: Spirit at Gusev crater. NASA.