MARS AFTER THE FLOOD; ROVER FINDS EVIDENCE OF PAST DELUGE.

Byline: Sherry Joe Crosby Daily News Staff Writer

Scientists at JPL found evidence Monday of a powerful flood that swept parts of Mars, as the Sojourner rover beamed back findings of jumbled rocks and ancient puddles from the Red Planet.

The flood, which was large enough to fill the Mediterranean Sea, carried boulders hundreds of miles away from the planet's highlands to the valley where the Mars Pathfinder spacecraft landed, Jet Propulsion Laboratory scientists said.

The flood also left behind puddles which ``bubbled up'' through volcanic ash, evaporated and formed crusty mineral deposits.

``It's like draining the whole Great Lakes region in a few days,'' said Donna Shirley, manager of the Mars Exploration Program. ``That size flood event was enormous. It was so fast it scoured and gouged rocks out of the landscape instantaneously and carried rocks downstream.''

There is no water on the planet now, but scientists believe the water was either lost to space or frozen underground in polar caps.

``The fact that a flood occurred means there was a lot of water on Mars, and nobody knows where it is,'' Shirley said. ``That's one of the mysteries.'' Shirley said evidence of the flood gives scientists clues about Earth's future environment.

``If we understand what happened to Mars in the past we can understand what Earth will be like in the future,'' she said. ``We wouldn't like to end up like Venus and we wouldn't like to end up like Mars.''

Mars has huge ozone holes and Venus is suffering from a runaway greenhouse effect, she said. Venus' surface temperature is 700 degrees - hot enough to melt lead.

At a briefing Monday at JPL, National Aeronautics and Space Administration scientists unveiled new photos of the rocky terrain, including the first picture taken from the rover back toward the lander.

During its third day of exploration, the solar-powered robot rover used its alpha proton X-ray spectrometer, a type of electronic snifter, to analyze a Martian rock dubbed ``Barnacle Bill,'' and is moving toward ``Yogi,'' another large rock.

Scientific results of ``Barnacle Bill,'' which is about the size of the rover, are scheduled for release today or Wednesday.

``These rocks yield clues to what happened on Mars billions of years ago,'' Mars Mission planner Wayne Lee said.

The rover also is conducting tests of the planet's loose soil. ``The goal is to gain a broad understanding of the Mars surface and its characteristics,'' Lee said.

Scientists also got a wider view of the planet by raising a camera up a 5-1/2-foot-high mast.

``We have a nice human height,'' Lee said. ``Those rocks that looked big and ominous, are not so big anymore.''

The images taken by the stereoscopic camera on the lander the first day were taken from 3 feet above the Martian surface.

With each new photo, scientists are piecing together a 360-degree panoramic shot that will enable them to examine the nuances of the planet's terrain.

``It's like a virtual 3-D image,'' Lee said. ``They can examine the landscape and tell how far apart the images are.''

The rover, centerpiece of the first mission to land on the surface of Mars in 21 years, has traveled a total of 16 inches over the past two days. Powered by a solar panel, it can travel about 2 feet a minute.

The landing July 4 marked NASA's and JPL's return to Mars for the first time since twin Viking orbiters arrived in 1976 and launched two landers to the surface.

JPL employees said the success of the Mars mission has increased morale at the campus.

``It's been a booster for our people,'' said Justin McNeill Jr., a software engineer who helped software for the imaging process used by Mars Pathfinder.

``It's all been positive, absolutely marvelous,'' said computer programmer Joe Witt said. ``I'm ecstatic for the people who worked on it. We need a boost.''

CAPTION(S):

2 Photos

PHOTO (1) An image from the Mars Pathfinder probe, released Monday, shows two hills in the distance, dubbed ``Twin Peaks,'' by Jet Propulsion Laboratory scientists.

(2) An image taken Sunday shows the Sojourner alongside the rock ``Barnacle Bill,'' from which it was gathering information.

Associated Press