Mars lander silent after descent

Anxious mission engineers at JPL await word from the spacecraft

December 3, 1999
Web posted at: 6:42 p.m. EST (2342 GMT)

In this story: Silence 'not entirely unexpected' Are Deep Space 2 probes OK? Search for water drives mission Taking pictures, recording sounds RELATED STORIES, SITES

From staff and wire reports

PASADENA, California (CNN) -- The Mars Polar Lander failed to make radio contact with Earth hours after its presumed landing, but NASA scientists maintain the probe could still have successfully touched down near the red planet's south pole.

NASA officials had hoped the lander would communicate Friday afternoon during one of two brief windows of opportunity with the Earth after a 3:01 p.m. EST touchdown. But the $165 million spacecraft, forced to turn its antenna away from the Earth during a harrowing descent, remained silent after a second downlink opportunity elapsed about 6 p.m. EST.

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Space agency scientists stressed that the lack of communication did not mean the mission was necessarily in jeopardy. The lander's antennae could require more time to locate a receiving station on Earth, they said.

Silence 'not entirely unexpected'

The silence was "not entirely unexpected," Richard Cook, the MPL project manager for operations, told reporters at NASA's Jet Propulsion Laboratory in Pasadena, California. Cook said he was "disappointed," but "very confident" that the lander survived the descent.

But the faces of JPL technicians revealed their concern, as worried looks replaced upbeat smiles from earlier in the day.

The next opportunity the lander could communicate with Earth, with a receiving station in Australia, will begin at 11:08 p.m. EST, according to NASA.

The Mars Climate Orbiter, which was lost in September due to a mathematical error, was to have served as a radio relay for the lander. The lander will have to send initial data directly back to Earth.

And NASA scientists plan to use the Mars Global Surveyor, currently orbiting Mars on a mapping mission, to relay data between the lander and Earth. Radio contact would indicate that the lander successfully parachuted through the thin martian atmosphere, deployed its lander legs, then fired its thrusters for a gentle, controlled descent to the frigid surface.

ALSO Mars Internet sites draw heavy traffic In Depth: Exploring Mars Mars Lander overview: The quest for water Along for the ride: Mars microprobes Lander to listen for the sounds of Mars

The lander has been on an 11-month voyage from Earth. Scientists hope the mission will reveal crucial information about the martian climate and possibly even signs of water ice buried beneath the planet's topsoil.

Awaiting word from Deep Space 2 probes

The spider-like craft was to set down in a never-explored region so close to the south pole that the sun will not dip below the horizon during the mission. Although late spring, the average temperature there is expected to be minus-73 degrees Fahrenheit (-58 Celsius).

Launched in January, the 3-foot, 600-pound lander would mark humankind's first return to the red planet since 1996, when the Mars Pathfinder mission sent its rover crawling across the rocky martian landscape. Besides the lander, NASA scientists have yet to make contact with two micro-laboratories that were to have separated from the main craft and crash to the martian surface about 60 miles (97 km) from the main landing site.

The Deep Space 2 probes, about the size of basketballs, were dubbed Amundsen and Scott after the first explorers to reach the South Pole on Earth. They are designed to examine the subsoil for signs of water. The first signals from the Deep Space 2 probes had been expected late Friday afternoon at the earliest.

Illustration of a Mars Microprobe (Click image for annotated graphic)

Search for water drives mission

If the other projects work as plan, the lander's instruments will measure vapor in the atmosphere, while a claw on the spacecraft will collect samples to be cooked and analyzed for water. The primary task of the 90-day mission will be to search for water, considered an essential prerequisite for life.

Water on Mars could also serve as a vital resource for future astronauts. Scientists know frozen water exists on the red planet in its northern ice cap. They believe there may be more underground, including around the south pole.

Taking pictures, recording sounds

The lander will also send back pictures -- black and white photos of its landing, followed by color pictures after touchdown. And for the first time, scientists will receive sounds from another planet, recorded by the Mars Microphone -- a device the size of a pack of Post-it notes and weighing less than 2 ounces (57 grams).

It's privately funded and has no scientific goal. The sounds will be posted on CNN.com and on the Planetary Society's Web site at www.planetary.org.

Correspondent Mile O'Brien and Reuters contributed to this report.