Fascinating planet
What's the reason for our fascination? Apart from being so close (relatively speaking - at its closest it is 55 million miles from us!) it has many similarities to Earth – it's rocky, has an atmosphere, and ice caps, and much evidence that there was flowing water in the past. The idea of sending humans to explore Mars and even colonise the planet has been much debated, and there are even serious plans by an organisation called 'Mars One' to put humans there by as early as 2024!
Life on Mars?
For many years people have speculated whether there is life on Mars. As well as five spacecraft now orbiting the planet (Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter, in addition to the two new ones), there are also two rovers exploring its surface (Curiosity and Opportunity), but so far, no life has been directly detected, certainly not the sort of 'Martians' described in sci-fi!
But plumes of methane gas have been spotted in some places, which could possibly be caused by organisms deep below the surface (although geological processes could also be responsible).
And although there is much evidence that water once flowed on the surface, such as the channels in this image, there is none now – where did it all go, and why?
Although Mars does have an atmosphere, it is very thin, about 100 times less dense than the Earth's, and made up mostly of carbon dioxide, with no water vapour – could it once have been dense enough and wet enough to support life? If so, why has Mars lost most of its atmosphere, and is the process still continuing?
Finding the answers to questions like these is crucial to the figuring out just how feasible it would be to send humans to explore and colonise this planet.
Measuring the atmosphere
A lot of the work of the new missions will focus on finding out more about the atmosphere. Mars Orbiter's instruments include one that will measure levels of methane, and MAVEN aims to study the planet's very thin upper atmosphere, by measuring for a year the rate by which hydrogen and oxygen is lost into space, enabling scientists to then figure out how much water has been lost from Mars over time.
And there is more to come– the European Space Agency's ExoMars programme, scheduled for 2016-18, will also be looking for signs of life and water both on the surface and in the atmosphere.
A lot of investment and energy is going into exploration of Mars, and I anticipate some exciting discoveries within the next few years. Even if a manned mission finally makes it to Mars, it's hard to imagine humans living and thriving on such a planet, but we are an inventive, creative species so who knows what the future could hold!
http://lasp.colorado.edu/home/maven/2014/09/24/maven-spacecraft-returns-first-mars-observations/
http://www.isro.org/satellites/mars-orbiter-spacecraft.aspx
http://exploration.esa.int/mars/46038-methane-on-mars/
http://www.universetoday.com/101325/more-evidence-that-mars-lost-its-atmosphere/
1.Mars Orbiter – Indian Space Research Organisation http://www.isro.org/pslv-c25/Imagegallery/mom-images.aspx#1
2. Jim Secosky modified NASA imagehttp://upload.wikimedia.org/wikipedia/en/6/69/Semeykin_Crater_Drainage.JPG
3. Laboratory for Atmospheric and Space Physics /University of Colorado and NASA http://lasp.colorado.edu/home/maven/2014/09/24/maven-spacecraft-returns-first-mars-observations/