OREGON STATE UNIVERSITY

OSU professor works to boost knowledge of Mars atmosphere

12/03/1998

CORVALLIS - Six years ago, Oregon State University researcher Jeff Barnes watched as NASA's Mars Observer streaked away from Earth to collect atmospheric data that Barnes and fellow scientists hoped to analyze for details about the Martian climate.

But, 11 months later, the unmanned Observer was lost - the victim of a propulsion system failure just before Mars arrival.

Now, as the National Aeronautics and Space Administration prepares for the Dec. 10 launch of the Mars Climate Orbiter, Barnes is hopeful that this time the data he and other scientists need to paint a clearer picture of Mars will be collected by the unmanned Climate Orbiter.

"I have a broad-ranging interest in the Martian atmosphere," said Barnes, a professor in OSU's College of Oceanic and Atmospheric Sciences. "I'll be looking at how the winds blow, and the distributions of temperature and pressure."

The launch is part of NASA's 1998 Mars Surveyor missions. Scientists hope the data will give insights into the nature of the planet's surface and atmosphere, as well as be used in preparation for eventual human visits to Mars.

Barnes is one of several OSU scientists working on Mars projects. Some campus researchers are working on clothing that will help astronauts learn how to walk in the low gravity they will face on Mars and others are working on robotic arms that could have application in outer space.

The Mars Climate Orbiter will be the first of two Mars launches in upcoming months, Barnes said. Staying true to its name, the Climate Orbiter is intended to collect data while circling the red planet. The Orbiter will be closely followed by the Jan. 3 launch of the Mars Polar Lander, which will attempt to touch down on the frigid, barren steppe near the edge of Mars' south polar cap. Both spacecraft will be launched atop identical Delta II launch vehicles from Cape Canaveral Air Station, Fla.

"It (the Orbiter) will be making 13 orbits per day in mapping orbit. While it will be looking at temperature, pressure and dust, it will also be measuring the amount of water vapor and ice in the atmosphere," Barnes said.

The Orbiter carries a specialized pressure modulator infrared radiometer that is capable of measuring temperatures, dust, water vapor and clouds by using a mirror to scan the atmosphere from the surface of the planet, up to about 50 miles, Barnes said.

Scientists already know a great deal about the planet, Barnes said, and are quickly finding that by Earth standards, the extreme is normal on Mars.

For example, the Mars atmosphere is so thin that it does not rain and any water that does make it to the surface quickly freezes or evaporates and floats about in the atmosphere.

"It is called the red planet because of the fine, reddish dust with a high iron oxide content," he said. "The winds are strong enough to lift it up and transport it all over the planet." The global dust storms are powered by surface winds of at least 80 mph.

Available data indicates that the average surface temperature is about minus 65 degrees, but can drop to as low as about minus 200 degrees. However, at times, temperatures can approach balmy levels, with midday temperatures near the ground in the Martian summer tropics getting well above freezing when Mars is at its closest approach to the sun.

Depending on the launch date, the Orbiter should reach Mars in September or October, where it will begin a circular, nearly polar orbit around the planet. Once in orbit, the spacecraft's instruments will operate for one Martian year (687 Earth days), Barnes said.

But Barnes cautions that the launch dates are uncertain. Any number of factors, including weather or equipment questions could cause delays. The Orbiter has a 16-day launch window, meaning the last day to launch is Dec. 26, while the Lander has a 25-day launch window.