ExoMars mission ready to look for signs of life

Mars - did it once hold life? Does it now? Photo credit: Getty

At ESA's Planetary Mission Control Room in Darmstadt, Germany, scientists are busily preparing for the next stage of the ExoMars mission.

Having arrived at the red planet in October 2016, the Trace Gas Orbiter has been gradually adjusting its orbit.

The spacecraft has now descended to an altitude of about 400km and is ready to begin its study of Mars.

"I'm looking forward to the next few months enormously because the TGO (trace gas orbiter) will finally be able to show its full capability, the full capability of its instruments, in terms of accuracy, and quantity, and quality of data, pictures, spectra," says flight operations director Michel Denis.

"And also, because we will be able to do start joint observations with our previous spacecraft at Mars, Mars Express."

The ExoMars rocket in 2016, prior to launch.
The ExoMars rocket in 2016, prior to launch. Photo credit: ESA

The TGO's primary mission is to identify gases in the Martian atmosphere, particularly the scientifically tantalising methane.

In 2014, NASA's Curiosity Mars rover detected spikes of methane in the planet's atmosphere.

Most of Earth's atmospheric methane comes from animal and plant life, and the environment itself, so Martian methane raises the question of past or present microbial life.

Or the gas elevations could come from geological sources, comet impacts or something else entirely.

"We know that the lifetime of methane is very short - just a few hundred years - it will be broken down by the sunlight, by the UV, ultraviolet component of the sunlight," says project scientist Hakan Svedhem.

"So, if it is there now, we know it has to be refilled all the time. And where does it come from? That's the big question."

Scientists hope the TGO's spectrometer will help them discover whether the methane comes from a geological or biological source.

ESA's ExoMars 2020 rover - set to arrive at the red planet in 2021 - will drill up to two metres beneath the surface to also search for evidence of life.

The orbiter will also act as a radio relay for the next stage of the ExoMars mission and future attempts to land on the planet.

"The so-called relay function allows us to communicate with all landers and rovers on the surface of Mars," says Denis.

"At the moment, there are only rovers and landers from NASA - Curiosity and Opportunity. Some tests had been done already soon after arrival at Mars and now we are going to start a campaign to calibrate and determine the best performance to relay data."

ESA scientists hope the work done in the next few months will help pave the way for future manned missions to the Red Planet.

"Mars, of course, has this very special thing, it's actually a place that you can imagine yourself walking on," says Mr Svedhem.

"Eventually within not too far in the future, surely people will be walking on Mars, that makes it very exciting.

"And then, to think about this idea that there might have been some kind of life or even exists today underground on Mars. That makes it a very special place."