Dr Louisa J. Preston is a Postdoctoral Research Associate at The Open University. Louisa is a TED fellow and tweets @LouisaJPreston.

A robotic planetary geologist landed on Mars at 6.31am GMT on Monday August 6th 2012. The appropriately named ‘Curiosity’ rover is NASA’s latest offering to help us determine whether past and/or present habitable environments exist on Mars. This car-sized, nuclear-powered mobile science laboratory is on a mission to Gale Crater, a 154 km diameter impact crater located just south of the equator. Here, scientists are hoping to learn about the environmental conditions that existed in the crater and whether these conditions would have favoured life.

Within minutes of being lowered onto the dusty surface, Curiosity transmitted back images of a beautiful sun drenched Martian vista. Since then hundreds of images have been returned to Earth, but none as breath-taking as Curiosity’s self-portrait captured by the Mars Hand Lens Imager (MAHLI). It was taken on Sol 84 and shows the rover, scoop marks, tire tracks and Mount Sharp rising in the background. Although I am not a member of the MSL team, like hundreds of scientists around the world, I am following the progress of the mission, eagerly awaiting the data Curiosity is collecting. I guess you could say we are Curiosity groupies.

NASA/JPL-Caltech/Malin Space Science Systems

Of the ten science instruments on board, the Sample Analysis at Mars (SAM) package is a particular focus of mine. It is a suite of three analytical tools designed to study chemistry relevant to life by checking for carbon-based compounds which on Earth are used as life’s molecular building blocks. Results from SAM are already coming in and will ultimately change how we view Mars by providing us with definitive evidence regarding its habitability potential. A positive result i.e. the discovery of organic compounds, will not necessarily mean there is life on Mars, just that conditions have existed at this site that might have allowed for it.

One major factor in whether Mars was ever habitable is the composition of its atmosphere, how this composition has changed over billions of years and ultimately what caused Mars to lose a large fraction of it. The first ‘sniffs’ of the Martian atmosphere by SAM have catalogued the most sensitive measurements to date. Initial results of atmospheric CO2 show an increase of 5% in heavier isotopes of carbon compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space. This provides weight to theories that in Mars’ distant past it may have had a thicker atmosphere and liquid water on its surface. NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission will investigate this question of atmospheric loss further when it arrives at Mars in 2014. Its main goal is to search for methane gas, a simple precursor chemical for life. SAM’s atmospheric measurements, however, so far reveal little to no methane. This gas is of interest as, on Earth, it is one of the most abundant organic compounds and can be produced biologically or by non-biological processes. If this isn’t enough work for SAM, it is also set to analyse its first solid sample in the coming weeks, beginning the search for organic compounds in the rocks and soils of Gale Crater. This will answer the question of whether Gale Crater was once, or possibly is currently, a habitable environment.

Another instrument making headlines is the Chemistry and Mineralogy (CheMin) experiment which provided the first analysis of Martian soil from within Gale Crater. Crystalline feldspar, pyroxenes and olivine mixed with some amorphous (non-crystalline) material was identified and this is similar to volcanic soils in Hawaii. Hawaii has long been considered a brilliant analogue environment for Mars, with this latest finding highlighting the relevance of planetary analogue research and opening the world’s eyes to the fact that, although the Earth and Mars may look very different, there are actually many similarities. I work in environments such as Hawaii, which is almost like visiting another planet in the study of the rocks, soils and life that thrive there. Some of these sites, such as Antarctica, are a little hard to get to, whereas others include the red acidic rivers of Rio Tinto in Spain, the volcanoes of Mt Teide in Tenerife and Mt Etna in Italy, hot springs in Iceland and Yellowstone National Park, and the hundreds of impact craters around the world, such as those in the Canadian High Arctic and Arizona. Looking at these places teaches us about the possibilities of life in similar environments and geological settings on Mars, what this life might look like and what tools and technologies we might need to find it.

Image from http://mdrs.marssociety.org/

This search for life on Mars is the cornerstone of Astrobiology, which is an enigma amongst science as it has yet to prove its subject matter actually exists i.e. we have not found extra-terrestrial life. This multi-disciplinary subject, however, is growing at an immense rate and now involves diverse fields such as geology, biology, chemistry, physics, history and medicine to name a few, all working together to answer humanity’s last great question – is there life beyond the Earth?