Lately, however, we have established a near-permanent presence, both above the planet, in the form of orbiters and on the ground, in a form of the famous rovers. In 1997 a little NASA Pathfinder rover opened up Mars to decades of intensive exploration. In 2004 now almost celebrity-like Opportunity and Spirit rovers landed on Mars and exceeded all expectations as to their expiration dates. Instead of the planned 3 month missions, Spirit went on to work for another 6 years and Opportunity is still, against all odds, exploring the mysterious world next door. In 2012 it will be joined with the Curiosity rover, a remarkable machine representing the very pinnacle of our technological advancement.
The more we explored Mars, the more interesting it seemed to get. We don't view it with naive optimism of the early days of the 20th century, nor do we share the pessimism of the scientific community of the 1970's. Instead, we see Mars as a real world, whose history we now understand, to some extent. We know that some 3-4 billions of years ago Mars had warm bodies of flowing water on its surface. We know that in the past there existed conditions on the surface of Mars suitable for life to emerge and to exist for relatively long periods of time. It had a thicker atmosphere. Just underneath the martian sand there are minerals that are formed, at least on Earth, exclusively with prolonged contact with warm, liquid water. We do not yet know whether there was life on Mars in the past, but there is circumstantial but tantalizing evidence of biological processes today.
There is an area on Mars where methane gas is released cyclically, following seasonal changes. It must be coming from underground because there is otherwise no indication of any abnormal activity on the surface of that area.On Earth most of methane gas is produced by living organisms and some is a byproduct of geological activity. In either case, it means that Mars has yet to exhale its last breath, figuratively speaking.
Astrobiologists found extremophile bacterial organisms on Earth that could survive and thrive on Mars. This means that not only could there have been life in the past, but that it could still survive there, in a highly primitive form.
NASA is executing and planning many exciting missions to explore Mars, a world that refuses to ease its firm grip on our monkey curiosity. Next year stay tuned for Curiosity's arrival. European Space Agency is also contributing to the exploration in the form of Mars Express, an orbiter examining martian surface in great detail. In the future NASA intends to even send an airplane that will fly over the area of methane gas intrigue, collecting data that is otherwise impossible to obtain from the orbit in space.