Crater and plains deposit northwest of Herschel Crater on Mars taken by the High Resolution Imaging Science Experiment (HiRISE).
Credit: NASA/JPL/University of Arizona
MELBOURNE: Dramatic new images of Mars have revealed volcanoes, lakes and ice on the surface of the red planet, thanks to NASA's latest Mars-orbiting satellite.
The pictures, taken by instruments on the Mars Reconnaissance Orbiter, are detailed enough to show ground level features of under one metre in size - a first for Mars photography - and will allow scientists to find the safest landing sites for future Mars missions. They may also help shed light on past climates, both on Mars and Earth.
"Mars has a tremendous diversity of geographical morphologies and processes, all of which we hope to study," said Alfred McEwen, a planetary geologist from the University of Arizona in Tucson, USA. McEwen is the lead researcher behind the project, and presented initial results at this week's International Conference on Geomorphology held in Melbourne, Australia.
Captured as part of the High Resolution Imaging Science Experiment (HiRISE), the collection of around 10,000 colour photos covers approximately 0.55% of the Martian surface. Each picture shows an area five to six kilometres wide, with a resolution of 25 cm to 60 cm per pixel. This provides an unprecedented level of detail - previous images of the Martian surface have had a minimum resolution of around 10 meters per pixel.
Taking such high quality shots involved overcoming a number of technical hurdles, McEwen explained. Firstly, the camera attached to the satellite needed to be at least five times lighter than similar technology, such as the satellite cameras used by google earth.
Secondly, as the camera is moving at a speed of over three kilometers per a second, the electronics used to process the images and send them back to Earth need to be very fast.
One exciting finding suggests that water was once much more common on Mars that previously thought. Now a cold, dry desert, pictures of layered sediment in the base of large craters provide startling evidence that Mars was once covered by lakes. Other images show lava spewed from an ancient volcano, whilst photos of dry ice at the Martian poles tell us that the red planet has seasons.
Knowing what the surface looks like, and where water might be found, could be extremely useful for future human visits. "We can scout out safe future landing sites," said McEwen. "The most valuable resource in space is water ice – once you know the water is there, you can melt it. Mars would be habitable."
Jon Clarke, a geologist from the Australian Centre for Astrobiology at the University of New South Wales in Sydney, is impressed by the image collection. "Its like flying over Mars and looking out from a plane," he said. "You can see things directly relating to the surface, like wind blowing across it."
Both McEwen and Clarke are hopeful that the images will also be useful for geologists studying earth. For instance, many rocks on Mars are much, much older than those on earth, most of which have been modified or destroyed by forces such as erosion or earthquakes.
Pictures of these ancient Martian rocks provide a snapshot of a time period that is completely missing from Earth's geological record, and could give scientists an idea of what earlier climates on earth may have been like. "Understanding alien climates helps us understand how our own planet works" said Clarke.
NASA's Mars Reconnaissance Orbiter is a multipurpose spacecraft was launched in August 2005 and attained Martian orbit in March 2006.
