Researchers going through the data obtained by NASA's Odyssey orbiter, have found signs of a surprising amount of water near the Martian equator, a region that was previously believed to be relatively dry. The Odyssey mission is the US Space Agency's longest operating orbiter around the Red Planet, and the new evidence of significant hydration is based on observations collected between 2002 and 2009.
The finding could have significant impact in the efforts for pioneering missions to Mars, or efforts to establish a permanent human settlement, and the colonisation of the planet by humans. One of the pre-requisites for humans for a base or a city on Mars would be the easy access to water, and it now looks like there is buried water ice below the Martian surface. The ice could be used for water supply to the pioneering bases or the colonies, as well as a raw material for producing hydrogen-based fuel.
The scientific payload used for the observations was the neutron spectrometer, which does not directly measure the amount of water in a region. Instead, it measures neutrons, which allows scientists to estimate the amount of hydrogen. An unusually large amount of hydrogen was found in the equatorial regions, which indicated the presence of water. However, in the region, water ice was not expected to be stable, no matter how deeply buried beneath the surface it was. Closer to the poles, the presence of hydrogen is an indicator of water ice.
A number of pathfinding missions to Mars in the next few years will benefit from the finding. NASA's Resource Prospector mission scheduled for 2020 will look to mine hydrogen, oxygen and water from the Martian surface. Water will also be needed to grow any crops grown locally to be eaten by future spacefarers. One of the significant part of the SpaceX plan to establish a permanent human settlement on Mars involves finding a location where carbon dioxide can be collected and water can be mined.
The confirmation of an abundance of water near the equatorial regions will reduce the amount of water that will need to be ferried from Earth, giving space to other payloads and instruments.
The process used by the researchers involved improving the imaging data by reducing the amount of noise. The image reconstruction techniques were the equivalent of reducing the altitude of the orbit of the spacecraft by half. However, the existence of water ice below the surface remains somewhat of a mystery, the researchers know that it could be there, but a conventional understanding of Martian geology does not allow for water ice to persist in the equatorial regions for very long.
The observed signs could indicate the presence of hydrated salts instead of water, but the presence of the salts are difficult to explain as well.
Jack Wilson, the lead researcher on the team that reprocessed the data says, "Perhaps the signature could be explained in terms of extensive deposits of hydrated salts, but how these hydrated salts came to be in the formation is also difficult to explain. So for now, the signature remains a mystery worthy of further study, and Mars continues to surprise us."