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Tuesday, August 7, 2012 - Page updated at 11:30 p.m.
Redmond rocketeers celebrate Mars landing
By Sandi Doughton
Seattle Times science reporter
The Redmond rocketeers who made the engines that guided the Curiosity rover to its triumphant landing on Mars Sunday night planned to continue the celebration today. After an anxious evening awaiting word, many of the 450 employees at the local branch of aerospace giant Aerojet wore red to work on Monday, and looked forward to an afternoon party.
"Oh my god, we're so excited," said Olwen Morgan, Aerojet's business-development manager. "The whole company is excited."
From the spacecraft's launch last November to its contact with Martian soil, 36 engines from Aerojet's Redmond operation played a role in the $2.5 billion mission.
Curiosity is the 13th Mars-bound spacecraft Aerojet program manager Jon Schierberl has worked on, and it never gets old, he said Sunday. "Every one of them is exciting."
Schierberl joined other space buffs listening to NASA's live broadcast at Seattle's Museum of Flight. "I'll be biting whatever fingernails I have left," he said, before learning of the successful touch down.
When NASA broadcast the official word shortly after 10:30 p.m. Sunday, the overflowing crowd at the museum burst into cheers.
The Redmond team started working on the Curiosity project in 1998. The spacecraft was launched atop an Atlas V rocket powered by boosters built at Aerojet's Sacramento, Calif., facility. A dozen engines from Aerojet's Redmond facility then steered the craft toward Mars, and eight more thrusters, small enough to fit in your hand, kept it on course during the 350 million-mile trip.
The company's local roots go back to 1959, when a group of entrepreneurs and former Boeing engineers founded Rocket Research in Seattle's South Park neighborhood. The company was acquired by Aerojet in 2002. The Redmond operation also makes the rockets that power GPS and telecommunications satellites.
Aerojet produced the propulsion and maneuvering systems for every spacecraft to visit Mars since Viking 1 in 1975 — orbiters, planetary probes and rovers alike. None of those missions demanded the elaborate series of moves that will be required to get the Curiosity rover safely to the surface, with Aerojet engines involved at every step.
If any one thing in the sequence of events went astray, the entire mission would be compromised, Schierberl said Sunday.
Because it takes 14 minutes for a command from Earth to reach the craft, onboard computers controlled the entire landing sequence. "It's completely on its own," Schierberl said.
With the capsule, including the rover and its saucer-shaped delivery vehicle, plunging into the Martian atmosphere at 13,000 miles per hour, heat shield glowing red-hot, eight Aerojet rockets kicked into action and guided the initial descent. The rover landed near the base of a 16,000-foot mountain in the center of a vast meteor crater.
Mars' atmosphere is too thin to slow the craft much below 1,000 mph, so a huge parachute was deployed, reducing the speed to about 200 mph. After jettisoning the heat shield and cutting the chute loose, another eight Aerojet engines were the only thing standing between the spacecraft and a crushing impact.
Actually, four engines would have been enough to do the job, but almost every key part on the spacecraft was doubled — just in case, Morgan said. "There's a lot of redundancy."
As radar in the underside of the craft scanned the ground, the powerful Aerojet engines were switched on and off by computers, braking the capsule and guiding it downward. In the final approach, the thrusters held the craft in a near-hover above the ground, setting the stage for NASA's elaborate finish.
The Curiosity rover, a six-wheeled dune buggy the size of a small car, detached from the delivery craft and was lowered on cables the final few feet. The rover itself carries no propulsion engines.
But Aerojet's handiwork still had one crucial task to perform: disposal of the delivery craft. The engines fired and sent the now-useless hulk careening out of the way to a safe crash site.
The signal that the rover had landed successfully was relayed to Earth about 14 minutes later, via a Mars-orbiting satellite, which is also powered by Aerojet engines.
The plan is for Curiosity to spend about two years exploring Mars' geology and searching for signs that the planet most like Earth might once have harbored life, or at least its building blocks.
To ensure that quest would not be compromised, Aerojet uses liquid hydrazine fuel that contains no carbon.
"You don't want to go to Mars and say: 'Look, I found life,' " Morgan said, "then have to say: 'Oh nuts. I brought it myself.' "
Sandi Doughton: 206-464-2491 or firstname.lastname@example.org
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