Mars Mission’s Dress Rehearsal Set for Arizona : Exploration: A plot with dunes and volcanic rocks at the University of Arizona is being readied as a practice spot for landings on the Red Planet.

Graceful red dunes and volcanic rocks spread carefully over a courtyard on the campus of the University of Arizona are the practice grounds for a $150-million robot mission to Mars, America’s third visit to the Red Planet.

The 1,600-square-foot plot has turned scientists into gardeners, groundskeepers and bird chasers. But if their little bit of Mars works as planned, it will help develop the equipment for NASA’s Mars Pathfinder mission set for launch next year.

Staff and students at Arizona’s Lunar and Planetary Laboratory shoveled 79 tons of orange-red soil into a courtyard of a classroom building and then sculptured it into a gently rippled plain resembling a river valley on Mars. Volcanic rocks from nearby mountains completed the barren scene.

“I doubt you’ll find a place just like this on Mars,” said Daniel T. Britt, manager of Arizona’s part in the mission, “but we tried to duplicate some of the terrain our craft will find when it gets there.”

Keeping the plain pristine has been the biggest chore.

Britt said he’s had to spend time out of his lab and working as a gardener.

“I’ve been picking out weeds,” he said. “This isn’t Mars. It rains here and plants grow.”

The scientists also have had to pick up debris and shoo away birds who apparently think the loose soil is an ideal comfort station.

They also fenced the Martian yard to keep animals away from the kitty litter-like surface.

“If a cat got in there it would be a disaster,” said one Arizona staffer.

The scientists also have to spend time removing white paint chips that flake off from nearby buildings and speckle the red soil.

In March, more than 40 international space scientists will gather at the Marscape to test, for the second time, the Pathfinder mission equipment.

Mars Pathfinder is due for launch next December and is scheduled to touch down in a place called the Ares Tiu Outflow Valley on July 4, 1997.

The mission is a showcase of NASA’s concept of smaller, quicker and cheaper voyages of exploration. The cost was limited to $150 million, which is small as space missions go, and the project was formally started just over a year ago.

Not much bigger than a steamer trunk, the whole spacecraft will fly directly to Mars and then fall to its surface. A parachute and braking rockets will slow the 582-pound craft, but the final jolt will be cushioned by 12 air bags, rather like those in modern cars.

“It’s going to hit and then bounce and bounce and bounce,” said Britt. “But it’s designed to survive no matter how it lands.”

When the craft comes to rest, three petal-like panels will open and a six-wheeled buggy will roll out.

The buggy, called Rocky by engineers at the Jet Propulsion Laboratory in Pasadena, is just 24 inches long and 18 inches wide. It will be capable of roving out to more than 30 feet. Three cameras on the buggy will relay close-up views to the spacecraft, which will beam them to Earth.