The European Space Agency's ExoMars spacecraft is set to blast off on top of a Proton rocket on Monday (14 March). Scientists hope they will find traces of life – past or present – on the red planet. This will be the ESA's first mission to Mars since the failure of the Beagle-2 lander in 2003.
The aim of the mission is to search for evidence of methane and other trace atmospheric gases that could signal whether there is or has been life on Mars. Methane breaks down in sunlight within a few hundred years, so if any is identified in the atmosphere, researchers will know it had to come from somewhere relatively recently. That "somewhere" could either be from volcanoes, or living microorganisms.
The mission is the first stage in ESA's ExoMars programme. The second, in two years' time, will see the ESA flying a British-built robotic rover to the surface of Mars. It will then drill down seven feet into the planet's surface to locate the methane-producing microbes.
"Mars has become very interesting scientifically because it was proven that Mars has a geological history which dates back ... hundreds of millions of years which is similar to that of the Earth," said ESA flight director Paolo Ferri. "It had water on its surface, now not anymore. It had a denser atmosphere, now not anymore. Something has dramatically changed which means that from a scientific point of view ... it is extremely interesting to explore Mars."
The mission will use a Trace Gas Orbiter to analyse Mars' atmosphere. This orbiter will do exactly that – orbit – approximately 400km from the surface of the red planet. It will send data back to Earth, detailing the percentage of methane, water vapour, nitrogen oxides and acetylene – all traces gases. The orbiter will also tell the scientists if any sulphur dioxide is present in the atmosphere. This is the key to uncovering what the source of the methane is (if there's any at all, of course). Sulphur dioxide implies that the methane is from a chemical source – such as volcanoes.
The Trace Gas Orbiter will also help astrobiologists in a second way – preparing for the ExoMars rover in two years' time. This robot has six legs, and can roam the surface of the Red Planet in search of life.
Ferri said that while the Americans had already successfully demonstrated how to land on Mars, Europeans still had to learn how to do it. Previous attempts at landing on Mars have had mixed fortunes. For example, the Beagle-2 lander was sent to Mars in 2003, but never responded when scientists tried to communicate with it.
Therefore, a practice run will be attempted by astronomers at the ESA. The TGO will deploy Schiaparelli – an entry, descent and landing demonstrator module – on 16 October 2016. This module will act just like a Mars rover would, plummeting towards Mars' surface at 21,000kmph (13,000mph).
Should Schiaparelli land safely, that means the ExoMars rover should land, too. However, this module is not just a robotic guinea pig. If the TGO manages to capture a source of methane, the module can roam about the surface of the planet – just like the Mars rover, albeit for nowhere near as long.
Possible signs of rudimentary life has previously come from Nasa's Martian rovers, which found soil and rocks that could only have formed in lakes or rivers. Other exciting research shows that Mars once had a magnetic field to protect it from the sun's radiation – as the Earth has today.
Mars is Nasa's prime focus these days. Astronaut Scott Kelly has just completed a 340-day mission at the International Space Station that's considered a scientific stepping stone for sending humans to the red planet in the 2030s. Another Nasa Mars lander — this one a car-sized, wheeled rover — is scheduled for a 2020 launch. The red planet already is teeming with active spacecraft, including Nasa's Opportunity and Curiosity rovers on the surface, and Odyssey, Mars Reconnaissance Orbiter and Maven orbiter from high above. Europe has its Express spacecraft in orbit around the red planet.
Asked whether he believed there was life on Mars, Ferri said: "I can't answer that today. It can be said that until now, it was sought unsuccessfully but we have researched so little of Mars. Mars is enormous so it really can't be excluded and we will continue to search."