JPL WAITING FOR MARS PROBE TO CALL IN.

Byline: Usha Sutliff Staff Writer

Anxious scientists, engineers, and a crowd of celebrities and journalists at NASA's Jet Propulsion Laboratory waited in vain Friday for a signal that the Mars Polar Lander made its 470 million-mile journey to the Red Planet safely.

After an hour with no word from the spacecraft, Project Manager Richard Cook held a news conference, trying to reassure all it was ``not an unexpected thing'' that the lander didn't check in early in the afternoon.

``I'm very confident that the lander survived the descent,'' he said. ``I think we're a long way from being concerned.''

Mission control engineers have a ``well thought-out contingency plan'' that they will use over the next four to five days as they try to contact their probe, he said.

``We don't plan on giving up anytime soon,'' he said.

The $165 million craft was scheduled to touch down on Mars at 12:01 p.m.

Once it landed, the spacecraft was to deploy its solar panels, the source of its power, and raise its dish-shaped antenna and point it toward Earth.

The lander then would have been able to transmit a signal that scientists would have received at 12:39 p.m.

At that instant, a hush fell over the engineers, journalists and visitors at JPL, and all activity stopped as people waited to hear something, anything from the lander.

The moments ticked by in silence and nothing came.

Engineers took a break about 1 p.m.

Cook declined to speculate about at what point he and the others would abandon the spacecraft as lost.

While no one mentioned it Friday, the loss of the Mars Climate Orbiter in September due to a failure to convert English measurements to metric units could not have been far from the thoughts of those concerned with keeping funding for NASA space exploration intact.

In the hours before the scheduled transmission time from near the Martian south pole, harried scientists and reporters from more than 100 news organizations from around the world scurried through the JPL press areas.

A live NASA TV feed was displayed on a large screen in the von Karman auditorium and showed mission-control engineers, along with NASA Administrator Daniel Goldin, California Institute of Technology President David Baltimore and JPL Director Ed Stone, crammed into the control room at the world-renowned lab.

Celebrities from the worlds of politics, business, science and Hollywood were also in attendance, including ``Titanic'' director James Cameron, who taped much of the real-life drama with a hand-held home video camera.

At 6:27 p.m., scientists sent a signal out into space to try to contact the lander. They planned to listen for a response between 8:08 and 10:40 p.m.

If that fails, the next window of opportunity for contact will open at 8:30 p.m. tonight.

There could be any number of reasons why mission control hasn't heard from the lander, said Randii Wessen, a JPL science system engineer.

One possible scenario is that the lander touched down on Mars and went into ``safe'' mode, a self-activated kind of protection it could choose if its sensors indicated anything out of place. That could have been triggered by factors such as tilting or settling into the Martian soil, he said.

Another possibility was that everything happened on schedule on Mars - the solar panels deployed, the antenna raised and the low-resolution and engineering data were transmitted - but scientists never got the signal and the lander went into a ``sleep'' mode, Wessen said.

``It means that (the antenna) is not pointed to Earth. . . . The lander may not know it has a problem,'' he said.

The mood among scientists at JPL was still one of guarded optimism, the engineer said.

``There are a lot of really mixed feelings. I mean, you don't want to think the worst. You know it was a really small probability that you'd hear things at 12:39 p.m., but you wanted to,'' Wessen said.

``Now the question is, Is it dead? Is it just going along its happy way and it's happy-go-lucky? . . . The mood gets more and more depressed with each attempt,'' he said.

But, he added, ``we won't call it quits for days. We don't give up on these things.''

The lander's mission on Mars is to search for evidence of water and learn more about the atmosphere. It was sent along with two Deep Space 2 microprobes, which will send their signals via the Mars Global Surveyor that is in orbit around the Red Planet.

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Photo: Like parents on prom night, NASA officials wait Friday to hear from the Mars Polar Lander, which was to phone home at 12:39 p.m.

Mark J. Terrill/Associated Press