NASA BUILDS TWIN ROVERS FOR MARS MISSION.

Byline: Usha Sutliff Staff Writer

LA CANADA FLINTRIDGE - Two identical rovers built at the Jet Propulsion Laboratory will be sent to Mars in 2003 to study the planet's geological history, NASA officials said Thursday.

``Millions of miles away, the Red Planet beckons to us with those age- old mysteries of did life ever form there?'' said Scott Hubbard, NASA's Mars program director.

``One way we ask that question is, Where did all the water go? We think that this twin rover mission will allow us to move even further toward answering that type of question,'' Hubbard said at a news conference at the agency's Washington, D.C., headquarters.

The decision to send the first rover was announced about two weeks ago. Since then, NASA officials have been evaluating their resources and deciding whether both roving geological explorers could be built and tested in time, he said.

``After carefully balancing and weighing all of these different issues, we concluded we can do this. Let's go for two,'' Hubbard said.

Thanks to the orbits of Earth and Mars, flight conditions will be especially favorable in 2003, Hubbard said. Less rocket energy will be needed to reach Mars and communications will be better, he said.

The first rover will cost about $350 million to $400 million to design and build, and the second, an exact copy, will cost roughly $200 million.

Edward Weiler, NASA's associate administrator for space science, said the space agency will not ask the White House to increase the budget to pay for the second ``SUV in a bag'' but will pull funds from other programs.

But, he added, that will not necessarily lead to the cancellation of other missions.

The decision to send two rovers was good news for JPL, which has plucked scientists who worked on the highly successful 1997 Mars Pathfinder mission - on which aspects of the future mission are based - to fill key positions on the 2003 team.

Weiler said he met with the 2003 team at the La Canada Flintridge facility recently.

``The room was overflowing - a lot of very young faces, young engineers and scientists, and the enthusiasm, the smiles,'' he said. ``It's clear that team wants this challenge. They're ready. I think they deserve the opportunity to try, and I think they'll be successful.''

At its peak, the project will employ about 300 scientists and engineers, more than 100 of whom have already been hired, according to Firouz Naderi, manager of JPL's Mars Program Office. A preliminary design review is set for October.

Both rovers will be launched on Delta II rockets from Cape Canaveral in Florida. The first will leave Earth on May 22, 2003, entering the Martian atmosphere on Jan. 2, 2004. The other rover will be launched on June 4, 2003, arriving at Mars on Jan. 20, 2004.

The landing sites have not been chosen but will likely include one that is relatively safe and another that is a bit riskier, according to Weiler.

The rovers' landings will use the same ``drop, bounce and roll'' technology that made history during the Mars Pathfinder mission.

At about 75 miles from the planet's surface, each spacecraft will be rushing in at 14,000 mph. When the spacecraft is about 7 miles from touchdown, a huge parachute will open, slowing it. A thousand feet before landing, a cocoon of air bags will inflate and like a giant superball, the spacecraft will bounce about a dozen times, rolling up to a half-mile before coming to rest.

Then the airbags will deflate and retract and the ``petals'' will open, bringing the lander to an upright position and revealing the rover, according to Naderi.

That's where the similarities to the trailblazing Mars Pathfinder mission end because the 2003 rovers - which have yet to be named - are much smarter and more ``robust'' than their smaller cousin, the Mars Pathfinder Sojourner rover, NASA officials said.

A clearly excited Steven Squyres, the Cornell University professor charged with developing the rovers' science instruments, described the wheeled robots as having ``almost human-like characteristics.''

At 4 feet tall and weighing about 300 pounds, the robotic field geologists are ``sort of short and fat,'' he said, with 20/20 vision and a robotic arm the same size and length of a human arm. The arm will be used to examine rocks for evidence of ancient water.

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An artist's illustration shows the new Mars 2003 Rover. NASA plans to double up on its planned 2003 landing expedition by dispatching two identical wheeled robots in search of geologic evidence of water on the Red Planet.

NASA/Associated Press