May 30, 2002. Copyright 2002. Graphic News. All rights reserved.

Embargo-release time: 12:00 p.m. Eastern Time, Thursday, 30 May 30, 2002

Odyssey discovers buried Martian ice

LONDON, May 30, Graphic News: Water ice has been found in vast quantities just below the surface of Mars. The discovery by NASAÕs Mars Odyssey spacecraft -- published in the journal Science -- is hailed as one of the most important made about the Red Planet. 

ÒThis is really amazing,Ó said William V. Boynton of the University of ArizonaÕs Lunar and Planetary Laboratory. ÒThis is the best direct evidence we have of sub-surface water ice on Mars. Indeed,Ó he added, Òwhat we have found is much more ice than we ever expected.Ó

The discovery solves one of its deepest mysteries, reignites the question of whether life may exist on the planet, and points the way for manned exploration, expected within the next 20 years.

For decades scientists have debated whether the planet was ever water-rich. Surface features that were first recorded by the Italian astronomer Giovanni Schiaparelli in 1877 suggested water had once flowed over the planetÕs surface. He called the straight lines that he saw Òcanali,Ó an Italian word meaning channels. The canali were also observed by nineteenth century Boston mathematician and Mars-watcher, Percival Lowell, who concluded they were canals built by intelligent beings. The canals supposedly supplied water from the melting polar caps to a desert world. 

Until this weekÕs announcement scientists had calculated that MarsÕ atmosphere contained about 0.016 percent of water vapour, compared to EarthÕs average level of about 2 percent. New data suggest that water -- in the form of water ice -- may be buried at shallow depths beneath the surface. If melted, the water ice would more than twice fill Lake Michigan in the United States.

Dr. Boynton is the principal investigator for a suite of instruments onboard Odyssey collectively known as the GRS (gamma ray spectrometer). The GRS has been mapping the flux of gamma rays (high-energy light) and neutrons from the planetÕs surface since February 2002. As cosmic rays bombard the planet, they interact with sub-surface hydrogen to produce neutrons and gamma rays, each with a specific signature.

OdysseyÕs measurements therefore provide an estimate of hydrogen concentration in the uppermost layers of the Martian crust. Through this mapping, the GRS indicates that the highest concentration of possible water ice layers may be buried 30 to 60 centimeters (12 to 24 inches) below the Martian surface from the edge of the polar ice caps to mid-latitudes of 60 degrees, covered by a thin, ÒdryÓ and hydrogen-poor layer. OdysseyÕs data suggest that 20 to 35 percent of the weight of the ice-bearing layer is water ice: ÒHeat up a bucketful of dirt and what do you get? A half-bucket of liquid water,Ó Boynton explained. 

BoyntonÕs colleagues, William C. Feldman of Los Alamos National Laboratory and Igor G. Mitrofanov of the Institute for Space Research in Moscow were amazed at the strength of the signature of the ice. They had expected to take a year to gather enough evidence but managed to do so in just a few weeks.

Water is essential for life, so discovering water just below the surface will be an enormous boon to astronauts on Mars. The discovery also enhances the belief that Mars could have had life in the past and perhaps in the present as well. Because of this, bringing a sample of the ice and rock back to Earth by an unmanned sample return probe will become a top priority. 

/ENDS

Sources: Science, NASA, Jet Propulsion Laboratory