Rover Curiosity has detected sporadic traces of methane on Mars, but now a study suggests that they could be linked to the rover himself.
Over the past ten years, NASA’s Rover Curiosity has detected sporadic traces of methane in the atmosphere of Mars, feeding speculations on the possible presence of microbial life. However, a recent study led by Sébastien Viscardy, published on Journal of Geophysical Research: Planetsraises considerable doubts about the reliability of these surveys, By suggesting that methane could have terrestrial origins or related to the rover itself.
Anomalies in measurements. The methane surveys carried out by the Curiosity laser spectrometer (TLS) show significant variations between the individual measurements, despite the averages indicate the presence of the gas. In addition, pressure fluctuations within the TLS compartments have been observed, designed to be hermetic, raising questions about the possible contamination of the samples analyzed by terrestrial air or by phenomena that would warn within the rover himself.
Contamination. Before the launch from Cape Canaveral in 2011 the terrestrial air penetrated the TLS room. Despite the subsequent evacuations of gas, high levels of methane have been detected in this compartment.
Previous studies had highlighted that materials used in the construction of the rover, such as the Kapton ribbon, could have been release methane when exposed to ultraviolet light. This phenomenon could contribute to methane surveys carried out by Curiosity, complicating the interpretation of the data.
An experiment to clarify the origin. To distinguish between a Marzian source and a terrestrial contamination, the researchers propose an experiment: analyze the same sample of Martian air for two consecutive nights. An increase in the concentration of methane in the second night would indicate a possible spill of methane from other parts of the rover, rather than from the planet itself.
Other sources. The presence or absence of methane is also controversial by the probes that seek it from the orbit of the planet. In 2004, Mars Express had detected traces of methane for the first time in the Martian atmosphere, using the Planetary Fourian Spectrometer spectrometer (PFS). The concentrations observed however, they were very lowabout 10 parts per billion (PPBV), but significant, since Methane on Mars should degrade quicklyindicating that it executes an active source of gas production.
Independent surveys. On June 15, 2013, NASA’s Rover Curiosity had detected a peak methane in the Gale crater. The next day, Mars Express confirmed independently of this detection, recording a concentration of about 15 PPBVs in the same area. This had been the first time that one Methane detection on Mars was simultaneously detected by two independent tools, one on the surface and one in orbit.
Exomars says “no”. Despite these surveys, the presence of methane on Mars remains controversial.
The Trace Gas Orbiter (Tgo) of the Exomars mission, launched in 2016, has never detected methane in the Martian atmosphere. This had led scientists to hypothesize that methane could only be present locally and temporarily, or that atmospheric mechanisms existed that destroy it quickly. Now, what Viscardy claims could exclude these hypotheses and also question the weak premises of one possible existence of life on the red planet.
