NASA MAY FLY ON NEIGHBOR PLANET; MARS EXPLORATION BY PLANE STUDIED ON EVE OF WRIGHT BROTHERS' FLIGHT CENTENNIAL.

Byline: Andrew Bridges Staff Writer

If it was the right stuff that carried the American space program through its early years, it may be the Wright stuff that will do the same in the next century.

To mark the 100th anniversary of Orville and Wilbur Wright's inaugural flight in a powered airplane, NASA hopes to replicate the feat - on Mars.

In 2003, the space agency plans to send a tiny, unmanned plane to Mars, packaged in an egg-like container roughly 30 inches across.

As it nears the Red Planet's surface, the spacecraft would jettison the tiny aeroshell, freeing the even tinier plane, which would unfold its wings and tail before swooping down into an enormous valley five times as deep as the Grand Canyon for a 15-minute, 100-mile-plus flight.

It would be the first time a winged vehicle of any type has flown on another planet.

Backers of the plane, which NASA Administrator Daniel Goldin enthusiastically endorsed in February, have targeted the $50 million project to fly on Dec. 17, 2003 - the 100th anniversary to the day of the Wright brothers' historic flight at Kitty Hawk, N.C.

``The hope is to hit on a spectacular day and do something spectacular with it,'' said Wendy Calvin, a research geophysicist with the United States Geological Survey, who spearheaded development of an early prototype with JPL and Monrovia-based AeroVironment Inc., a designer of high-tech unmanned aircraft.

The red-and-white prototype, nicknamed Otto for 19th-century German glider pioneer Otto Lilienthal, was rejected last year by NASA (along with a much larger plane proposed by NASA's Ames Research Center). But the team now hopes to repropose a similar model later this year when NASA begins soliciting proposals for the 2003 mission.

Carlos Miralles, an AeroVironment program manager, said Otto was purposely made a glider to save weight.

``What we realized was, it almost boiled down to you can carry a propulsion system or you can carry a payload,'' Miralles said. Whether the final version will glide or be propelled across Mars remains to be seen, however.

Beginning in February, the team began flying its radio-controlled, 22-pound prototype, dropping it from a balloon to test how well it unfolds. The team then sent it soaring on its 6-foot wingspan through Red Rock Canyon, north of Mojave.

They chose the desert spot because it resembles the Valles Marineris on Mars, a canyon system 2,400 miles long and more than five miles deep. Scientists hope to fly the Mars plane through the Valles, top to bottom, to image and measure with a suite of instruments its layered walls, each pancaked section a chapter in the planet's ancient past.

``We won't have to drill 10 kilometer-deep holes in the planet; we'll have it all there exposed,'' Calvin said.

But flying on Mars will be no mean feat: Its atmosphere is only 1 percent as dense as the Earth's at sea level, giving wings trying to generate lift a workout.

``The thin atmosphere forces you into a flight regime the world doesn't have a lot of experience with,'' Miralles said.

Traveling as fast as 180 mph, the plane would require a tremendous turning radius, making terrain avoidance tricky, if not impossible.

And compounding the problem, by the time it takes any command to make the one-way trip from Earth to Mars, the plane will likely already have crashed at the end of its 15- to 30-minute flight, requiring it to be absolutely autonomous in its operation.

NASA has tossed around the idea of flying a plane on Mars since the 1970s; so why now has the idea gained such currency, especially when the agency has undertaken an ambitious program to poke, prod, sample and image the planet using rovers, landers and orbiters?

Because planes fill a niche between all three, Miralles said.

Rovers, like Mars Pathfinder's Sojourner, can travel only short distances, generally in comparatively boring areas of the planet. And orbiters, like the Mars Global Surveyor, can get only so close to the planet's surface.

A plane, though, can cover great distances through rough - and thus geologically interesting - terrain.

``You will get a regional perspective you just can't get from a rover or a satellite,'' Calvin said.

The JPL/AeroVironment prototype, developed at the latter's Simi Valley design development center, has an impressive pedigree.

AeroVironment excels in building airplanes that fly at extreme altitudes - like the massive solar-powered Centurion it will test later this summer and hopes to later fly at 100,000 feet - or that are extremely tiny, like the Black Widow, a saucer-sized plane that made a 22-minute flight in early March.

Merge the two, Miralles said, and you have a plane capable of being tightly packed to make it to Mars and that can fly in its atmosphere, which is like flying at 100,000 feet above Earth.

What the Mars plane - or planes, as NASA may send two - will carry is still undecided as well. The team responsible for defining the instrument load has met just once; it will meet again this week at JPL.

Calvin said it is likely the plane will carry at the minimum a camera, a spectrometer to do analysis of the canyon walls' composition and a magnetometer to measure the planet's magnetic fields.

The Mars plane will be the first Mars Micromission, a class of lightweight missions NASA hopes to repeat every two years, said Steve Matousek, JPL's Micromissions study lead.

The missions will be piggybacked aboard a French Ariane V rocket. The French have promised NASA can carry about 500 pounds of spacecraft and payload aloft each launch, beginning in November 2002 when the Mars plane will blast off.

Although NASA has already realized the publicity value of the Mars plane and the prestige it would bring - Miralles said the competition among NASA's various centers, including JPL, to land the project is so fierce one consultant called it the biggest ``porkathon'' ever seen, but without the money, it will probably turn out to be more than a one-time stunt, experts said.

``If we are going to continue to explore Mars it is going to involve airplanes,'' said Mike Ravine, an advanced projects manager at Malin Space Science Systems, a San Diego aerospace company that collaborated on NASA Ames' competing Mars plane proposal.

CAPTION(S):

3 Photos

PHOTO (1--Color in Conejo and Simi Editions only) Carlos Miralles, project manager at Monrovia-based AeroVironment, shows the prototype of a plane being tested for a Mars flight.

(2-3--Color in Conejo and Simi Editions only) (Photo 2 ran in Conejo and Simi Editions only) (Photo 3 ran in Conejo, Simi and AV Editions only) NASA hopes to fly a plane across the surface of Mars in 2003, marking the 100th anniversary of the Wright Brothers' historic flight. A plane could offer the advantage of maneuverability.

Walt Mancini