Feb 2, 2011 16:04 GMT  ·  By
This is a rendition of how Hellas Planitia may have looked like billions of years ago
   This is a rendition of how Hellas Planitia may have looked like billions of years ago

Various missions sent to Mars by NASA and ESA have over the past few years demonstrated that the planet was once covered with water over huge stretches. Now, an effort to combine all data from missions to our neighbor is revealing additional insight into how it looked liked in the past.

There hasn't been any water on the Red Planet for at least a billion years, experts say, but the body held on to some pretty impressive liquid water reserves before its orbit changed drastically.

All the water that once adorned its surface can now be found at the bottom of deep craters throughout the planet, and under a thin, insulating layer of sand at areas around both poles. The latter fact was evidenced by the Phoenix Mars Lander in 2008.

Experts know that the water is there from data collected by the geology rovers Spirit and Opportunity, by the Mars Odyssey orbiter – which determined the path the waters took, and other orbiters such as the MRO and the Mars Express spacecraft of the European Space Agency (ESA).

Together, all these assets collected a massive wealth of data over the decades, from the 1970s and 1980s onwards. Experts collected data both from the surface and from orbit, and are now able to piece those information in a single product.

The goal here is to understand how water was distributed on the surface of Mars and why. The most important conclusion derived thus far is that a region known as Hellas Planitia, which is located in the southern Martian hemisphere, was once filled with water.

The area has a diameter of some 2,000 kilometers, and an average depth of 8 kilometers. A rendition of what it may have looked like is available in the image attached to this article. The mapping project is led by experts at the Planetary Science Institute, in Tucson, Arizona.

According to their map, significant amounts of sedimentary deposits can be seen as the fine-layered outcrops around Hellas’s eastern rim, in the new view. The rocks were deposited between 4.5 and 3.5 billion years ago, shortly after Mars was formed.

“Our mapping and evaluation of landforms and materials of the Hellas region from the basin rim to floor provides further insight into Martian climate regimes and into the abundance, distribution, and flux of volatiles through history,” says PSI expert and team leader Dr. Leslie Bleamaster.

He adds that Hellas Planitia – as a landscape feature – was produced when a massive space rock impact the Red Planet early on in its history. The structure is even now the largest impact basin on the planet.

“This really confirms that there was an ocean on Mars,” explains University of California in Berkeley (UCB) professor of earth and planetary science Mark Richards. He is also the dean of mathematical and physical sciences at the university, Daily Galaxy reports.