FAYETTEVILLE, Ark. - The NASA philosophy for finding life on Mars is simple: follow the water.

A $500,000 challenge grant from the W.M. Keck Foundation of Los Angeles will enable Derek Sears and his students and colleagues to investigate how liquid water forms on Mars and examine the existence of considerable amounts of near-surface ice all over the planet. They also will study how slight changes in pressure and temperature could transform Mars into a wet planet hospitable to simple life forms. Additionally, a laboratory used by Sears, a professor of chemistry in Fulbright College and director of the Arkansas-Oklahoma Center for Space and Planetary Sciences, will be renovated and named the W.M. Keck Laboratory for Space Simulation at the University of Arkansas.

The W.M. Keck Foundation, established in 1954 in Los Angeles by William Myron Keck, is one of the nation's largest philanthropic organizations. For half a century, the foundation has supported pioneering discoveries in science, engineering and medical research. The name is associated with some of the most innovative research programs and facilities in the country.

"People have always been fascinated by the prospect of life on Mars," said Sears. "With the support of a high-profile foundation such as Keck, I am confident that we'll find the additional funding we need to match the award and fully realize the potential of our research."

Together with Barney Farmer, distinguished visiting scientist, and Michael Hecht, research scientist, both from the NASA Jet Propulsion Laboratory in Pasadena, Calif., Sears will study the conditions under which liquid water could form on Mars today and whether water on the planet could remain stable long enough to sustain life. The W.M. Keck Foundation grant will enable the team to present their findings at international conferences and to offer graduate assistantships and research funding for doctoral students.

The researchers will employ a large stainless steel environmental chamber, dubbed Andromeda, that holds up to a half ton of Hawaiian volcanic dust, which shares chemical characteristics with Martian soil. The chamber can replicate most properties of Martian atmosphere, surface pressure, temperature and radiation.

The team will investigate five problems key to understanding the existence of water on Mars: the evaporation rates of water under a variety of conditions, today and in past epochs; the evaporation rate of various brine solutions, linked by some to the famous gullies on the planet; the melting and evaporation rates of both water and ice from sun-warmed surfaces in cold atmospheres; the lateral transfer of water and ice by sublimation; and the behavior of ice under a layer of dust.

The last investigation, and the most ambitious, offers the greatest potential for finally demonstrating that liquid water has existed or still does exist on Mars. Frozen water makes up as much as 10 percent of the top three feet of land in some regions close to Mars' equator. The dust may be acting as an insulator for lingering ice.

"The interactions of dust and ice offer the most likely explanation for water on Mars," said Sears. "What's tantalizing is how close Mars is to the triple point of water, the point at which ice, liquid and steam can exist together in equilibrium. On Mars, the surface remains below the triple point of water. You cannot have liquid water. But it's very close. Little is needed to make water, and very little indeed is needed to make the planet suitable for life."

Scientists theorize that over 3.5 billion years ago, half the Red Planet was covered with water and experienced catastrophic floods. Today, Mars looks like a barren desert, with dust storms at times enveloping the entire rocky and cold planet. In some ways, it looks strangely like Earth, with ice caps, seasonal changes, gullies and volcanoes.

The Viking missions in the 1970s found no organic life but in 1976 discovered that the northern permanent ice cap was composed primarily of water ice and measured seasonal variations in water vapor. In recent decades, Tim Kral and his students at the U of A have used the Andromeda chamber to explore whether life originated under anaerobic conditions. If so, organisms might be able to survive on Mars without organic matter or oxygen.

Images from recent missions have revealed vestiges of groundwater seepage and surface runoffs. New findings from NASA's Mars Odyssey orbiter suggest Mars may be going through a period of climate change. Odyssey has been mapping the distribution of materials on and near Mars' surface since early 2002, nearly a full annual cycle on Mars.

In 2004, the Opportunity rover collected samples of sulfate minerals that indicate large amounts of water were once present on the surface. Rolling into the crater Endurance, Opportunity investigated a jagged ridge of sharp peaks called "Razorback," which very likely formed as a result of water flowing through cracks and depositing hard minerals.

"Science is always a cultural, never entirely an esoteric undertaking," said Sears. "The possibility that life on Earth is not unique will represent a major advance in our understanding of the solar system - and of ourselves as well."

This gift counts toward the $300 Million Challenge, the campaign-within the Campaign for the Twenty-First Century. The purpose of the Challenge is to raise $300 million for academic purposes to match the Walton Family Charitable Support Foundation's $300 million gift to the U of A. Challenge funds must be raised between Jan. 1, 2002, and June 30, 2005, the end of the Campaign. The Challenge total stands at $194.3 million, and the overall Campaign total stands at $830 million as of June 30, 2004.