Feature

Pad Abort-1: A Test That Goes Off Like Clockwork
05.06.10
 
By: Jim Hodges and Amy Johnson

Everything went off on the dot. Everything.

At 9 a.m. Thursday, a flash on the screen at Reid Conference Center was greeted with applause by a small gathering, most of which had large portions of their life invested in the Orion Launch Abort System.

The flash signaled the beginning of the Pad Abort-1 test of the LAS, of engines unleashing up to 500,000 pounds of thrust in an instant to power the LAS off the pad at the White Sands Missile Range in New Mexico at 445-600 mph for 2 to 2.5 seconds.

And then more applause when the screen showed the vehicle being reoriented, part of a chain reaction of events that included one more burst of power, to jettison the LAS from the crew module, which parachuted to Earth successfully about 7,000 feet from where the system was launched.

At White Sands, where a crowd of more than 1,000 watched the test in the early morning light, Becky Bales of NASA Langley, LAS Deputy Manager for Project and Planning Control, called it "inspiring."

PA-1 launch.

Pad Abort 1 launched May 6 at White Sands Missile Range, N.M. Credit: NASA.

Click on the image for a larger view

And Kevin Rivers, a Langley engineer who was the LAS project manager, said at White Sands, "By all accounts, it was a totally successful launch, which is evident in the tremendous talent and sacrifices of such a great team across NASA and industry."

The work of the propulsion system got Ed Nemie excited. A systems engineer with ATK, he was particularly concerned with its engines, which propelled the LAS from its launch, though the change of attitude to separation from the crew module.

"It looked perfect," he said at the Reid Center. "It looked just like the animation."

When those parachutes deployed, Bethany Schiller counted the test a success. Thought she had cheered each step of the way, she remained nervous until the 'chutes opened because she has been working on that part of the test since 2007.

"I was nervous when we got to 10 seconds (before the launch)," she said. "Seeing everything happen the way it did in the animation is very exciting."

Animations are optimum. So many rocket launches look different in reality because of the sheer force involved. Pad Abort-1 seemed to follow the pre-launch animation as if it were a roadmap.

"It's very gratifying," said Greg Stover, a Langley engineer and the project manager when LAS began. "So many people have put so much time in this."

One of those was Rivers, who moved over from the Ares-1X program to LAS when Stover moved to another job.

"I like to think that one of these days that I'm going to be a grandpapa with grandbabies sitting on my knee, and I'll be able to tell them all of these stories they don't want to hear about all of the wonderful things I did when I was here," Rivers said. "This is one of the things I will be telling them."

The story will be of a $220 million program to build a $25 million piece of hardware that everyone hopes fervently will never have to be used. The Launch Abort System is designed to lift the crew module off a space vehicle in distress. One was never used in the Apollo program, in which NASA sent astronauts to the moon.

A launch abort system of any kind has been used only once, by the Soviet Union's Soyuz on Sept. 27, 1983, when a fire broke out on the ground and the crew capsule was lifted away. While touring Dryden Flight Center, Vladimir Titov, a cosmonaut aboard that Soyuz capsule, signed the Orion crew capsule mockup that was built at NASA Langley and which drifted down under the parachutes after being lifted aloft by the Launch Abort System.

The LAS project involved about 40 Langley personnel and 60 from Marshall Space Flight Center, which provided oversight on the propulsion that's provided by the three solid-fuel motors: one to separate the crew module/LAS away from the rocket; another – called an "attitude-control motor" -- to reorient the assembly for its descent to Earth; and a jettison motor to pull it away from the crew module, which then drifts down.

The most complicated of the three is the "attitude-control motor," and it has been the most time consuming to integrate into the system.

"It's a first of its kind, or more accurately, it's the first of its class," Rivers explained. "It's the motor in the nose of the rocket, and there are eight nozzles around the perimeter of the rocket. We have valves in the system that can distribute the thrust to specific nozzles and vector the vehicle along a specific trajectory.

"It's making decisions based on an algorithm that it executes about which nozzles to open to what levels to produce thrust and in what direction."

Essentially, the vehicle is steered by those thrust changes.

Along the way, the engineers consulted with counterparts who worked on the Apollo program in an attempt to retrieve some of the knowledge that would otherwise have been long lost.

"That's actually been one of the things that, sitting in meetings with those guys who actually worked Apollo has been terrific," said David McGowan, from Langley and the chief engineer on the LAS project.

But the Orion LAS and that of Apollo are radically different, in part because of the advancement of technology over the past five decades.

"Our ability to abort far exceeds the abilities to abort that were in the Apollo program," Rivers said. "They had very specific areas during the ascent flight in which they were unable to abort successfully. They blacked out those areas.

"I think our autonomous control capabilities are better. Our propulsion systems are better. Our control system is better."

So, too, is their ability to collect data.

There were 692 sensors along for the ride Thursday, and they will provide Pad Abort-1's legacy.

"We're going to learn an enormous amount from just the measurements we're making about the aerodynamic environment, the acoustic environment, the loads that we will experience during flight," Rivers said. "All of that data is going to be used to improve our understanding of how these things perform in flight, as well as help us build better tools or improve the tools we have to predict what those environments will be."

To what end?

NASA's new look envisions an effort toward exploring space beyond low-earth orbit, leaving the close-in work to commercial interests. Those interests are still building rockets.

"I think that any space transportation system is going to benefit by what we have done to date and what we'll continue to do in the future," Rivers said. "Be it a commercial low-earth orbit system or the beyond-low earth orbit system that we're going to be working on, there will be a benefit."

That much of its engineering has been led by Langley – coupled with the successful Max Launch Abort System effort of NASA's Engineering Safety Center last year – could make the center the place to start for anybody looking for launch-abort system help.

But that's for the future. This is now.

"We've learned everything on the ground we can learn," Rivers said. "Now it's time to fly."

Because there was plenty to learn from 95 seconds in the air.

 
 


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