Mars' dust key force on atmosphere, surface features
Posted: June 30, 2002

Texas A&M University researcher Mark Lemmon has been selected as member of a science team for a mission to Mars next year.

No, Lemmon won't personally be visiting the Red Planet, but his experiment will be part of the 2003 Mars Exploration Rover Mission, consisting of two identical robotic rovers scheduled for launch in mid-2003, to arrive at separate destinations on Mars in early 2004. Part of the rovers' mission will be to get a better handle on the nature and accumulation and dissipation patterns of Mars' signature red dust.

According to most scientists who study the Mars, dust is the defining feature of the planet's atmosphere and may constitute the major force eroding the planet's surface, much like the role played by water on the Earth.

"Understanding Martian dust will help scientists resolve a number of issues, including the correct color of images sent back to Earth," said Lemmon, a research scientist with the Department of Atmospheric Science in the College of Geosciences. "A panoramic camera will look at the landscape and sky, and possibly get a glimpse of Martian dust storms and dust devils."

Lemmon, who while at the University of Arizona was also on the Mars Pathfinder imaging team in 1997 and the 1999 Mars Polar Lander science team, is hoping to facilitate scheduling of images such as night-time pictures of Mars' moons, Phobos and Deimos, including photos of formation of morning fogs on Mars and shots of Phobos eclipsing the sun.

"But one key part of my experiment focuses on measuring the amount of dust in Mars' atmosphere," Lemmon said. "That's a tricky measurement from Earth -- when we look at Mars, we see a dusty atmosphere on top of a dusty surface. Knowing where the dust is helps us understand Mars' weather and climate, since atmospheric dust plays an important role in heating the planet's atmosphere.

"Knowing about dust in the sky is also important to the mission, since this dust blocks some of the sunlight that would fall on the rovers' solar panels and falls onto the solar panels, making them less effective," he observed. "So the more we know about the dust, the more we understand how much solar power we'll have for our instruments on Mars."

Lemmon's work was one of 28 new projects chosen for inclusion in the rover mission. In all, 84 proposals were submitted to NASA, which chose those judged to have the best science value for mission inclusion. All 28 investigators are part of the existing Athena science payload team and will work with the rover project at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

According to NASA officials, the rover mission has six science objectives:

(1) study rocks and soils for clues to past ater 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.

Lemmon previously held a visiting faculty appointment in Texas A&M's Department of Physics.

"We are excited to have Mark join our department," said Jerry North, head of the Department of Atmospheric Sciences. "Planetary atmospheric research brings a new and exciting dimension to our efforts."

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