Hopes are high in sky at Thiokol Company built 2 key parts of craft set to land on Mars today

Failure would mean crash

Pathfinder would be 1st landing to hit planet since 1976

Science

July 04, 1997|By Ted Shelsby | Ted Shelsby,SUN STAFF

It's nail-biting time for the folks working at Thiokol Corp.'s rocket motor plant in Elkton, as the Pathfinder spacecraft zooms in on Mars.

Pathfinder is NASA's latest effort to explore the Red Planet. It will carry a remote-control rover, named Sojourner, that is no bigger than a child's wagon. The six-wheeled vehicle will amble out in search of rocks and will carry instruments to analyze the composition of rocks and soil.

If things go as planned, it will be the first spacecraft to land on Mars since 1976.

But the success or failure of the $196 million, seven-month mission will depend on the operation of two key components manufactured by workers at Thiokol's solid-fuel rocket-engine plant in Cecil County.

"We'll have our fingers and our toes crossed," said David K. McGrath, the project engineer who oversaw development of the retro-rocket, which is responsible for slowing the spacecraft for a soft landing on the surface of Mars, which is scheduled for about 1 p.m. today..

The small rocket -- 34 inches long and five inches in diameter -- is to burn for only three seconds, but the firing is vital to the craft's survival. It is to take place as the Pathfinder is within 150 to 160 feet of the planet's surface.

The Elkton plant also produced the gas generators that are to inflate the six-foot-tall airbags -- similar to those in automobiles -- that will be used to further cushion Pathfinder's landing. The airbags surround the spacecraft and act like a cocoon to absorb the impact of hitting the Mars surface at about 55 miles an hour.

The airbags are scheduled to inflate about 900 feet above the surface, Thomas J. Kirschner, the designer of the gas generators, said.

"If everything goes as planned, the airbags will inflate in a second and a half," Gary L. Mionske, a senior engineer who built the generators, said.

The biggest challenge was to build a unit that would produce a gas cool enough not to destroy the airbags, Mionske said.

"We had to come up with a way of cooling the gas from about

degrees to 700 so it wouldn't burn the bags," Kirschner interjected.

If either of Thiokol's systems fails to perform, the Pathfinder will crash on the planet's surface and be destroyed, said Steven J, Goldstein, manager of new business support at the Elkton plant.

"There will be a lot of anxiety around here Friday afternoon," he said. "People will be mighty nervous until we get word that everything went well."

Even after the Pathfinder begins its descent, the Thiokol workers will have to wait before they know if their efforts succeeded or were crushed on the face of Mars. "We won't know until 5 or 6 p.m., when the first signals come back from Mars, if everything worked," said McGrath. "Until then we will be doing a lot of praying.

He expressed confidence in Thiokol's performance, but added: "in testing, you know of all the little problems that can come back and bite you. The things that can go wrong."

For example, NASA's $1 billion Mars Observer probe spun out of control just days before it was due to enter the planet's orbit in 1993.

The Elkton workers have already passed one major hurdle in their participation in the Pathfinder probe.

The company made the STAR-48 rocket booster that was used as the third-stage of the Delta rocket that was used to launch the spacecraft from Cape Canaveral on December 4 of last year to begin its 310 million-mile odyssey.

"Launching a rocket and getting it on the way to Mars is the easy part of this mission," said Goldstein. "We've done that before. But landing is where the challenge is. We're trying a new technique. It's a new challenge. That is what makes everybody nervous." Pathfinder's designers opted for air bags for the first time ever to see how well spacecraft can land in rugged terrain. The probe is expected to bounce a dozen times, as high as 40 feet, before it comes to rest.

The day after Pathfinder's launch, Tony Spear, NASA's project manager for the spacecraft, said the descent through the Martian atmosphere and landing would be 100 times more nerve-racking than the launch.

McGrath agrees. He said he and other workers at the Elkton plant will be anxiously waiting for the first signals back from the Pathfinder. "We'll be anxious," he said, "but we are pretty confident that our stuff will work as advertised.

"We have a lot of pride in what we do here," said McGrath. "It feels good to say that something I worked on is on another planet. Not many people can say that."

Thiokol's Elkton plant opened in 1948. But the operation was moved to Huntsville, Ala., later that year. It returned to Maryland in 1950.

Since then, the complex, which produces solid-fuel rocket motors, has been involved in about 90 percent of the satellites launched in the free world, said Donald R. Reed, director of engineering.

For instance, it was a retro-rocket made at the Elkton plant that slowed John Glenn's Mercury spacecraft to allow it to return to Earth.

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