Mars holds vast stores of water ice right near the surface and away from the permanently frozen south polar ice cap, scientists said today in announcing first major science findings from NASA's Mars Odyssey spacecraft.
The discovery makes it all the more possible that life may have once existed on Mars or could still be supported.
"There's a lot of ice on Mars," said William Boynton, a University of Arizona researcher who is the principal investigator for the Gamma Ray Spectrometer suite of instruments, used to make the discovery. "We really have a whopping large signal."
That signal is of hydrogen, one component of water. Boynton and his colleagues are confident the new measurements represents actual water ice at the surface and down a few feet. They said, however, that additional observations are needed to confirm the results.
Scientists already knew there was water locked up in the northern ice cap, along with carbon dioxide ice. But life is thought to require liquid water. So finding water ice nearer the equator greatly boosts the chances that it might melt seasonally or at least periodically, and could therefore potentially support life.
The findings were detailed at a press conference at the Jet Propulsion Laboratory, which manages the Odyssey mission for NASA, and they build on preliminary data reported in December. Odyssey's science mission officially began Feb. 19, but some data and images have been gathered since the craft first went into orbit around Mars on Oct. 23.
Boynton said the northern hemisphere might contain similar amounts of water ice, but that won't be determined until it is summer there and the large polar cap recedes. The cap's seasonal component is largely carbon dioxide ice and it masks what might be underneath.
Today's findings are just a glimpse of what's to come, said Stephen Saunders, an Odyssey project scientist from JPL.
"For the first time we're seeing elementary chemicals on the surface of Mars," Saunders said. "Our Odyssey has just begun."
Other signs of water
Scientists have long suspected that water once flowed freely on a warmer Mars. Supporting evidence has mounted in recent years, thanks mostly to the Mars Global Surveyor, another NASA spacecraft orbiting the planet.
As Mars cooled millions or billions of years ago and surface water froze or evaporated into space through a thinning atmosphere, some may have remained frozen in the soil or trapped in underground reservoirs.
Heat from within may still keep some of that water in liquid form, some scientists speculate. Or, underground water ice might be periodically melted by this geothermal activity. Research has not shown conclusively whether Mars is still geothermally active, however.
Surveyor's most significant discovery was evidence of seasonal deposits that could be associated with surface springs, first reported by SPACE.com in June of 2000.
Surveyor and Odyssey will both continue to explore Mars for more signs of liquid water on and below the surface.
About Odyssey
Odyssey, a mission costing nearly $300 million, launched April 7, 2001. The spacecraft is 7.2 feet (2.2 meters) long, 5.6 feet (1.7 meters) tall and 8.5 feet (2.6 meters) wide.
The orbiting craft will study Mars for at least three years from 249 miles (400 kilometers) above. It will map the planet in visible and infrared light in unprecedented detail, scientists say.
Odyssey is also scheduled to measure potentially deadly radiation with the Martian Radiation Environment Experiment (MARIE), an instrument that so far has not been made to work. Engineers are developing solutions and remain hopeful that MARIE will function.
The next planned mission to Mars is a pair of robotic surface rovers that would launch in 2003. The rovers will be able to sift dirt and crack upon rocks, then photograph the results and analyze sample for chemical signs of water and life.
The new findings and other results expected from Odyssey will help scientists decide where to put the rovers.
More about water on Mars
Odyssey Special Report
CompleteCoverage of the Mission and Findings
advertisement
