That is one of the major scientific questions of our time, and the European Space Agency is searching for an answer with its ExoMars mission scheduled to take off from Baikonur in Kazakstan in mid-March.
The ExoMars Programme is lead by the European Space Agency (ESA) in collaboration with the Russian Federal Space Agency':http://exploration.esa.int/mars/46048-programme-overview/
'ExoMars is the dream mission,' says Álvaro Giménez, Director of Science and Robotic Exploration at ESA. 'It is a mission where we are expecting to get the answer to the question we have about Mars – its life, its evolution… But also how or what that does it mean for the whole evolution of the Solar System, including Earth.'
The estimated time of arrival, after a seven-month journey, is in October. The Schiaparelli module – named after the 19th century Italian astronomer – will land on the Martian surface as the Trace Gas Orbiter goes into orbit to study the planet's atmosphere.
'Since it will be the first mission landing during the global dust storm season, we will conduct measurements during the descent that will allow us to determine important parameters of the atmosphere at this time of the year that has not been studied so much,' explains ExoMars project scientist Jorge Vago.
The main objectives of the mission are to search for evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes.
Evidence has been found of water on Mars and, back in December 2014, small traces of methane were found by Nasa's Curiosity Rover. On Earth, around 90% of methane is produced by living organisms, so the investigation is focused on what kind of source could emit methane on Mars
According to Nicolas Thomas, Principal investigator of CaSSIS (the Colour and Stereo Surface Imaging System), 'We are going and looking in great detail at the gas complements inside the atmosphere, and also looking for the potential of locally generated gases, which might be indicative of, for example, near-surface volcanic activity. It could even be connected to the release or sublimation of water, releasing gases that are trapped and, of course, we can talk a little bit about life, as a biological element to it… although I freely admit I'm a sceptic,' he adds.
The ExoMars programme will also test a number of essential flight and on-site technologies necessary for future exploration missions. These will include the entry, descent and landing of a payload on the surface of Mars, surface mobility with a rover and sample acquisition, preparation, distribution and analysis.
'So all of these will look forward to other missions and our own industry in Europe that may want to try to land also during this time of the year,' explains Jorge Vago. 'And, of course, it will be important for future missions, including astronaut missions.'
The ExoMars Programme consists of two missions. The next one, scheduled to be launched in 2018, includes a rover that will carry a two-metre drill and instruments dedicated to exobiology and geochemistry research. The rover's mission will be to search for possible fossils, digging much deeper into the Martian surface than has ever been done before.