Friday, January 07, 2000

Crippled Mars Lander Could Be in Crater -- NASA

PASADENA, Calif. (Reuters) - The ill-fated Mars Polar Lander, last heard from on Dec. 3, 1999, as it started a descent to the surface of the Red Planet, may be lying crippled in a huge crater, the chief mission scientist said on Thursday.

But Richard Zurek, the Mars Polar Lander Project Scientist, said the crater theory was just one of several scenarios being considered by scientists at NASA's Jet Propulsion Laboratory in Pasadena. He said the three-legged craft was heading in the direction of the crater when it hit the Martian atmosphere.

``There is a large crater in the western portion of the landing zone which contains rougher terrain than what we've seen elsewhere,'' Zurek told reporters.

He described the crater, close to the Martian south pole, as being about two thirds of a mile deep and covering an area the equivalent of California's vast Central Valley, which measures several thousand square miles.

The sides of the crater slope at 20 degrees, which would send the lander tumbling to the bottom of the crater. It was designed to land on slopes no greater than 10 degrees.

Zurek said that after flight controllers at Martin Lockheed in Golden, Colorado, had performed a fourth flight correction maneuver a few days before the lander reached Mars, scientists realized they were drifting west and toward the huge crater.

``We had planned a fifth and final correction for a few hours before the landing to push the lander more to the east, but we realized that maneuver would also push us too far to the south, so we chose to control the ... landing path. We expected we would have landed a bit north of the crater,'' he said.

But he said there were so many variables that the final resting place of the $165 million lander might never be known, unless the Mars Global Surveyor satellite, which has been mapping the Red Planet since 1997 and is photographing the landing site, can find its long white parachute -- the largest single object with the tiny craft.

One of those variables is the Martian wind, which can howl through the atmosphere at nearly 70 mph, kicking up huge dust storms.

Zurek said that if the winds were coming from the east they could possibly have blown the craft over to the crater.

Zurek said the Global Surveyor, which started looking for the lander two weeks ago, will continue its search for another two weeks. The best hope is the satellite will be able to take pictures of the craft's 65-foot long parachute draped across the surface, because the tiny lander is too small for the satellite's cameras to pick up.

``If we find the parachute we will know that the lander is no more than a kilometer (two thirds of a mile) away because if everything went right the two would have separated one kilometer above the surface and there wouldn't be much distance between them when they came down,'' he said.

Zurek said the investigation into what happened is far from over and the crater theory is just one possibility.

``We have not ruled out anything. We have not yet found any piece of information that tells us it's the landing site, the flight system, the radar system -- a whole host of things could have caused us to lose the lander,'' he said.

And he described a story in Thursday's Denver Post in which unnamed engineers at Lockheed Martin were quoted as saying the crater was probably the most likely theory as ``premature.''

Zurek also disputed the claim that Lockheed Martin was not told of the crater until two weeks after the lander disappeared.

``No one on our side knew that canyon was there. All of a sudden, two weeks later, we got this ... data'' -- essentially Martian topographical maps and images -- ``and it was like, 'Look at that hole!' Everybody was fairly surprised to see that data,'' the unnamed source told the Denver Post.

Zurek said, ``Data was showing the canyon when we picked the landing site. This was exposed to the team at Lockheed Martin.''

Dr. Noel Hinners, Vice President of Astronautics Flight Systems at Lockheed Martin, said that while the crater landing was one scenario, ``We have no knowledge, zip, zero, of what went wrong. We don't know anything for sure. The door is still wide open. The (Denver Post) article is totally false.''

He agreed that finding the craft's parachute was paramount in the investigation. ``If we see the parachute it tells us we had good separation from THE cruise stage, we really know where we landed. The hunt for parachute is very important,'' he said.

The failure of the Mars lander was NASA's second major loss at the Red Planet in three months. In September 1999 the Mars Climate Observer satellite was lost due to human error as it approached the planet, bringing the total loss to $265 million.