On Mars, dust rules. Red dust is omnipresent on the Red Planet. There are
dunes everywhere. Dust floats in the thin Martian air and whirls about the
planet in dust storms and dust devils, and falls out of the air and onto
Mars’ rocky features.

On Mars, says Peter H. Smith, dust is the defining feature of the
atmosphere, much like water and the hydrological cycle is the major force in
Earth’s atmosphere. Like water on Earth, dust is the major force eroding the
surface of Mars.

Smith, a scientist at the University of Arizona Lunar and Planetary
Laboratory in Tucson, whose IMP camera was perhaps the most publicly notable
success in the Mars Pathfinder mission several years ago, is one of more
than two dozen scientists who will participate on the next NASA mission to
Mars.

The Mars Exploration Rover (or MER), which is actually two vehicles that are
designed to study the Martian environment, is scheduled for launch about a
year from now in 2003. The two rovers are targeted to land on two separate
parts of Mars in early 2004.

Smith is one of several scientists who will be looking at the dust cycle on
Mars.

"Not much is known about the dust on Mars," Smith said. "We’ll be looking at
how dust piles up on surfaces, how it accumulates and how it gets off of
surfaces."

Smith says this wasn’t the initial goal of the MER mission, but NASA has
recognized its importance, judged, he said, by the number of atmospheric
scientists included in the mission. That includes Mark Lemmon, an
atmospheric scientist from Texas A&M University, one of Smith’s longtime
collaborators.

Lemmon says understanding Martian dust will help scientists resolve a number
of issues, including the correct the color of images sent back to Earth. A
panoramic camera will look at the landscape and sky, and possibly get a
glimpse of Martian dust storms and dust devils.

Smith said he was probably included on the mission in part because of his
expertise with calibrating remote controlled cameras, like the IMP on
Pathfinder. And unlike Pathfinder, the MER vehicles will be significantly
larger and be able to rage many miles instead of just a few hundred yards.

Smith and Lemmon and the 26 others were selected from 84 submitted projects.
They will work with the MER Program Office at NASA’s Jet Propulsion
Laboratory (JPL), Pasadena, Calif., and will become full MER science-team
members, joining previously selected scientists as part of the Athena
science team, according to NASA.

"The breadth, scope, and creativity of the scientists selected is very
encouraging," said Dr. Ed Weiler, NASA Associate Administrator for Space
Science, Headquarters, Washington. "By directly participating in NASA’s next
mission to the surface of Mars, they will help bring us closer to the
long-term objective of our Mars Exploration Program – understanding Mars as
a planet and determining whether life ever existed there."

NASA officials say the MER mission science objectives include: (1) study
rocks and soils for clues to past water activity; (2) investigate landing
sites that have a high probability of containing evidence of the action of
liquid water; (3) determine the distribution and composition of minerals,
rocks and soils surrounding the landing sites; (4) determine the nature of
local surface geologic processes; (5) calibrate and validate data from
orbiting missions at each landing site; and (6) study the geologic processes
for clues about the environmental conditions that existed when liquid water
was present, and whether those environments were conducive for life.