WE'RE BACK; AMERICA RETURNS TO MARS; RED PLANET PHOTOS BEAMED BACK.

Byline: Tony Knight Daily News Staff Writer

The unmanned Mars Pathfinder space probe landed safely on the Red Planet on Friday sending back panoramic color pictures of a boulder-strewn plain with low hills in the distance.

In a spectacular success for the National Aeronautics and Space Administration and Pasadena-based Jet Propulsion Laboratory, the landing and first day of the mission came off almost without a hitch.

It began with a 2,000-pound spacecraft bouncing to a stop on a cushion of air bags as a distant Earth rose over the horizon in the Martian night.

It ended with the display of a stunning panorama of crystal-clear images showing the rust-colored Martian soil covered with dark brown boulders stretching away to low hills etched against a pink Martian sky.

``The camera is our eyes, and in a sense we are all there together,'' said Peter Smith, principal investigator for the Pathfinder cameras. ``Open your mind to the experience and the beauty of landing on Mars.''

Plans to deploy the probe's little rover, Sojourner, were postponed until today while mission engineers make adjustments to provide a better path for it get to the surface.

The landing 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.

The risky Pathfinder mission, which literally shot the lander directly into the Martian atmosphere like a bullet, came off without a glitch to the surprise and delight of engineers and scientists at JPL, where the planetary probe was designed and built.

``This is really a spectacular day,'' said project manager Richard Cook, as the first images of a rocky Martian landscape were returned to Earth.

``It's gone better than we ever could have imagined,'' he said. ``We're pinching ourselves asking each other if this is real. But we're on the surface of another planet, and in the next few days and weeks we're going to learn a lot about ourselves and our solar system.''

Vice President Al Gore called JPL at midday to personally congratulate NASA Administrator Daniel Goldin, JPL Director Ed Stone, and mission flight systems manager Brian Muirhead on the success of the low-budget mission.

``This new way of doing business, faster, better, cheaper, is really being borne out with tremendous success,'' Gore said. ``The whole country is very proud of what you are doing and have done today.''

Goldin, who has reshaped the space agency in recent years and had demanded that Pathfinder be launched 38 short months from project approval, was ecstatic.

``What a birthday present,'' Goldin said. ``The people who planned and executed the Pathfinder mission weren't afraid to take risks and try something different just like the people who founded this country.''

Clearly in the celebratory mood after the lander began returning data, Goldin walked into the press room at JPL carrying his 3-year-old grandson, Zachary.

``He's going to walk on Mars some day,'' he said.

The landing marks the beginning of a 10-year NASA program to explore Mars, the most Earth-like of the solar system's other planets, a place that many scientist's theorize could once have harbored life.

Pathfinder and its rover won't be able to search directly for life, but Pathfinder's ability to analyze rocks could help scientists learn whether the planet could have supported life in its distant past.

The 23-pound rover will spend at least seven days exploring the rock strewn Martian landscape to a distance of about 100 yards.

The lander will take atmospheric measurements and study the surrounding geology using a set of 12 filters over its cameras to help determine the composition of rocks.

The four-sided lander was designed to open like a blossom with the rover on one petal.

The first pictures returned showed that a deflated air bag was partially blocking the area where the rover's descent ramps were to be deployed.

Scientists worked on the problem into the evening sending commands for the rover to lift the blocked petal and use on-board winches to reel the air bag in further.

The high point of the day was the risky landing. The signal that Pathfinder had safely come to rest was received at mission control in Pasadena just before 10:08 a.m. PDT.

It was met by a chorus of whoops, cheers and hugs among the JPL scientists and engineers.

The triumph was shared by television audiences around the world watching the NASA TV feed carried live on CNN.

Rob Manning, flight director, whose team designed and built the air-bag landing technology and who called the play-by-play as signals were received from Mars, turned to the camera and winked, giving a ``thumbs up'' sign.

``Back to Mars!'' shouted Wesley Huntress, NASA's associate administrator for space exploration, his arms raised in triumph from his seat in a JPL auditorium.

This was the first planetary landing in which the spacecraft plunged directly into the atmosphere of another planet, and the first use of the air-bag cushion for landing.

``This was a bold move to land directly on Mars with air bags and it appears we have landed safely and have an operational system,'' said JPL director Stone.

The 1,900-pound space probe had hurtled through more than 300 million miles of space on its flawless, seven-month cruise to Mars.

At landing, Mars was 120 million miles from Earth and the one-way travel time for radio signals at the speed of light was 10 minutes and 39 seconds.

In a flawlessly executed landing, the spacecraft entered the Martian atmosphere at 16,600 mph, streaking from northeast to southwest across the Martian sky, its heat shield blazing from friction with the thin air.

Slowed by the atmosphere, the spacecraft was still going about 1,000 mph when a parachute was automatically deployed slowing its speed to 120 mph.

On board radar measured the distance to the surface as the lander separated from its upper shell and extended down on a long bridle. The air bags then inflated to form a 17-foot-wide protective cushion.

At 50 feet above the surface, three retrorockets on the upper shell fired, the bridle was cut, and Pathfinder plummeted to the surface, bouncing at least three times across the rocky plain in a southwesterly direction.

Data collected during the landing and transmitted to Earth early in the afternoon indicated that the probe had bounced about 45 feet high the first time and actually gained momentum as it spun across the Martian surface.

The four-sided lander could have come to rest on any side and still would have been able to right itself. But on a day when it seemed nothing could go wrong, it even came to rest right side up.

``What's the odds of rolling to a stop on the base petal?'' said Manning. ``I lost that bet.''

The spacecraft landed about 35 miles southwest of dead center on the 120-mile-wide target area.

The region in which the lander now sits is called Ares Vallis, a rock-strewn plain thought to have been once deluged under a great flood.

This is the second of NASA's Discovery missions. The first to launch was the Near Earth Asteroid Rendezvous, which returned images of the asteroid Mathilde last week, and is continuing to a close fly-by of the Manhattan-sized asteroid Eros.

At $171 million, Pathfinder is a sharp contrast to the $1 billion Mars Observer, which was lost just before it entered orbit around Mars in 1993, probably due to a fuel explosion.

The two Viking missions that flew two orbiters to Mars and dropped two landers to the surface in 1976 would have cost $3 billion in today's dollars, NASA officials said.

FACTS ABOUT MARS

NAME: The fourth planet from the sun was named for the Roman god of war. It's called the Red Planet because of its reddish dust and soil.

SIZE: At 4,217 miles across it's about half the size of Earth and twice the size of Earth's moon. It has only one-tenth Earth's mass.

ORBIT: It follows an elliptical orbit with an average distance from the sun of 141.5 million miles. It revolves around the sun once every 687 days.

DAY LENGTH: A Martian day, called a sol, is 24 hours, 37 minutes and 23 seconds.

MOONS: Mars has two moons. Phobos, the Greek word for fear, is about 16 miles wide. Deimos, Greek for terror, is about 9 miles wide. Both were personified in Greek mythology as sons of the god of war.

ATMOSPHERE: Mars has a thin atmosphere composed of about 95 percent carbon dioxide and nearly 3 percent nitrogen. The atmospheric pressure at its surface is about 1/100th of Earth's average.

GRAVITY: Only 38 percent of Earth's.

SURFACE TEMPERATURE: Ranges from about minus-200 degrees Fahrenheit at the poles to as much as 80 degrees Fahrenheit at its equator when it is closest to the sun.

NOTABLE FEATURES: Its highest point is a volcano named Olympus Mons, more than 52,000 feet high. The canyons of Valles Marineris are the largest and deepest in the solar system, extending more than 2,500 miles with a depth of 3 to 6 miles. Mars appears to have channels cut by ancient rivers. Pathfinder is headed for Ares Vallis, an ancient flood plain formed by the equivalent of flushing all the water in the Great Lakes into the Gulf of Mexico in about two weeks.

SOURCE: Associated Press

CAPTION(S):

2 Photos, Box, Drawing

Photo: (1--Color) The surface of Mars is shown in a photo transmitted from NASA's Mars lander Pathfinder which made a successful landing on the Red Planet on Friday.

(2) Members of the Mars Pathfinder Project at Pasadena's Jet Propulsion Laboratory celebrate a flawless touchdown Friday.

Associated Press

Box: FACTS ABOUT MARS (See text)

Drawing: The Sojourner

The 25-pound rover is scheduled to leave the lander and begin a week of experiments on the planet's surface. A closer look at the vehicle

Associated Press