Flood of Evidence in Martian Dirt: First Samples Studied from Curiosity Reveal more Water in Red Planet's Soil than first thought
- Mars rover found that surface soil contains two per cent water by weight
- Sample also revealed carbon dioxide, oxygen, and sulphur compounds
- Future Mars explorers may find all the water they need beneath surface
Nasa’s Mars rover Curiosity has found water in the first soil sample taken from the red planet's surface.
The first scoop of soil analysed by Curiosity revealed that fine materials on the surface of the planet contain two per cent water by weight.
Study lead author Laurie Leshin, Rensselaer Polytechnic Institute's Dean of Science, said: ‘One of the most exciting results from this very first solid sample ingested by Curiosity is the high percentage of water in the soil.
Nasa's Mars rover Curiosity has found water in the first soil sample taken from the red planet's surface
THE DISCOVERY OF WATER ON MARS
Evidence of water on Mars dates back to the Mariner 9 mission, which arrived on Mars in 1971.
Mariner 9 imaging revealed clues of water erosion in river beds and canyons as well as weather fronts and fogs.
Viking orbiters that followed caused a revolution in our ideas about water on Mars by showing how floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.
Mars is currently in the middle of an ice age, so liquid water cannot exist on its surface at the present time. However, the planet seems to have been warmer and wetter in the past.
In June this year, Curiosity rover found Powerful evidence that water good enough to drink once flowed on Mars.
‘About two per cent of the soil on the surface of Mars is made up of water, which is a great resource, and interesting scientifically.’
The sample also released significant carbon dioxide, oxygen, and sulphur compounds when heated.
Curiosity landed in Gale Crater on the surface of Mars on August 6th last year, to try and find out if Mars could have once supported life.
To do that, Curiosity is the first rover on Mars to carry equipment for gathering and processing samples of rock and soil.
One of those instruments was employed in the current research: Sample Analysis at Mars (SAM) which includes a gas chromotograph, a mass spectrometer, and a tunable laser spectrometer.
These instruments enable it to identify a wide range of chemical compounds and determine the ratios of different isotopes of key elements.
Paul Mahaffy, principal investigator for SAM at NASA's Goddard Space Flight Centre, said: ‘This work not only demonstrates that SAM is working beautifully on Mars, but also shows how SAM fits into Curiosity's powerful and comprehensive suite of scientific instruments.
Curiosity landed in Gale Crater on the surface of Mars on August 6th last year, to try and find out if Mars could have once supported life
‘By combining analyses of water and other volatiles from SAM with mineralogical, chemical, and geological data from Curiosity's other instruments, we have the most comprehensive information ever obtained on martian surface fines.
‘These data greatly advance our understanding of surface processes and the action of water on Mars.'
Doctor Leshin added: ‘This is the first solid sample that we've analysed with the instruments on Curiosity.
‘It's the very first scoop of stuff that's been fed into the analytical suite. Although this is only the beginning of the story, what we've learned is substantial.’
In the study, published in the journal Science, researchers used the rover's scoop to collect dust, dirt, and finely grained soil from a sandy patch known as ‘Rocknest.’
They fed portions of the fifth scoop into SAM. Inside SAM, the ‘fines’ - as the dust, dirt, and fine soil is known - were heated to 835 degrees Celsius.
'About two per cent of the soil on the surface of Mars is made up of water, which is a great resource, and interesting scientifically,' according to lead researcher Laurie Leshin
Baking the sample also revealed a compound containing chlorine and oxygen, likely chlorate or perchlorate, previously known only from high-latitude locations on Mars.
This finding at Curiosity's equatorial site suggests more global distribution. The analysis also suggests the presence of carbonate materials, which form in the presence of water.
In addition to determining the amount of the major gases released, SAM also analysed ratios of isotopes of hydrogen and carbon in the released water and carbon dioxide.
Isotopes are variants of the same chemical element with different numbers of neutrons, and therefore different atomic weights.
SAM found that the ratio of isotopes in the soil is similar to that found in the atmosphere analysed earlier by Curiosity, indicating that the surface soil has interacted heavily with the atmosphere.
Dr Leshin said: ‘The isotopic ratios, including hydrogen-to-deuterium ratios and carbon isotopes, tend to support the idea that as the dust is moving around the planet, it's reacting with some of the gases from the atmosphere.’
She said the results shed light on the composition of the planet's surface, while offering direction for future research.
Dr Leshin added: ‘We now know there should be abundant, easily accessible water on Mars.
‘When we send people, they could scoop up the soil anywhere on the surface, heat it just a bit, and obtain water.’ __________________