Posted on 01/19/2008 11:03:55 PM PST by anymouse
NASA is wrestling with a potentially dangerous problem in a spacecraft, this time in a moon rocket that hasn't even been built yet.
Engineers are concerned that the new rocket meant to replace the space shuttle and send astronauts on their way to the moon could shake violently during the first few minutes of flight, possibly destroying the entire vehicle.
"They know it's a real problem," said Carnegie Mellon University engineering professor Paul Fischbeck, who has consulted on risk issues with NASA in the past. "This thing is going to shake apart the whole structure, and they've got to solve it."
If not corrected, the shaking would arise from the powerful first stage of the Ares I rocket, which will lift the Orion crew capsule into orbit.
NASA officials hope to have a plan for fixing the design as early as March, and they do not expect it to delay the goal of returning astronauts to the moon by 2020.
"I hope no one was so ill-informed as to believe that we would be able to develop a system to replace the shuttle without facing any challenges in doing so," NASA administrator Michael Griffin said in a statement to The Associated Press. "NASA has an excellent track record of resolving technical challenges. We're confident we'll solve this one as well."
Professor Jorge Arenas of the Institute of Acoustics in Valdivia, Chile, acknowledged that the problem was serious but said: "NASA has developed one of the safest and risk-controlled space programs in engineering history."
The space agency has been working on a plan to return to the moon, at a cost of more than $100 billion, since 2005. It involves two different rockets: Ares I, which would carry the astronauts into space, and an unmanned heavy-lift cargo ship, Ares V.
The concern isn't the shaking on the first stage, but how it affects everything that sits on top: the Orion crew capsule, instrument unit, and a booster.
That first stage is composed of five segments derived from the solid rocket boosters that NASA uses to launch the shuttle and would be built by ATK Launch Systems of Brigham City, Utah.
The shaking problem, which is common to solid rocket boosters, involves pulses of added acceleration caused by gas vortices in the rocket similar to the wake that develops behind a fast-moving boat, said Arenas, who has researched vibration and space-launch issues.
Those vortices happen to match the natural vibrating frequencies of the motor's combustion chamber, and the combination causes the shaking.
Senior managers were told of the findings last fall, but NASA did not talk about them publicly until the AP filed a Freedom of Information Act request earlier this month and the watchdog Web site Nasawatch.com submitted detailed engineering-oriented questions.
The response to those questions, given to both Nasawatch and AP, were shared with outside experts, who judged it a serious problem.
NASA engineers characterized the shaking as being in what the agency considers the "red zone" of risk, ranking a five on a 1-to-5 scale of severity.
"It's highly likely to happen and if it does, it's a disaster," said Fischbeck, an expert in engineering risks.
The first launch of astronauts aboard Ares I and Orion is set for March 2015.
On the Net:
NASA's Ares and Orion program:
http://www.nasa.gov/mission_pages/constellation/ares/index.html
Six times a hoax.
When I was a kid, we were lighting off Indian fireworks. I had a nice fountain that had a picture of the firework in a bottle with all sorts of Hindi writing all around the picture. Being a sensibel lad, I figured that this meant that you should put the thing in a bottle and light it.
Long story short, I put the thing in a bottle, it goes off in a beautiful shower of sparks for about 30 seconds, then falls into the bottle and explodes. I was about 30 feet away at the time, and I still have the scars in my legs to show off. How nobody was seriously injured, I will never know.
I took another of the fireworks and took it inside and showed it to our cook, and asked him what the writing said. It said "DO NOT PUT FIREWORKS IN BOTTLE".
On the bid for the shuttle solid rockets, there were at least two types. 1, was a single segment and would be built in Florida and shipped to the launch site. I think that was Aerojets'. The other one is the current one made by originaly, Morton Thiokill. It was in segments made in Utah and shipped by train to Florida. Guess who won the bid? This was when James Fletcher was an admin and had a supposed connection to Utah.
They built one 40 years ago and they can’t build one today?
Ya’ got it SAL. Thanks to LBJ we couldn’t build a new SR-71 to save our a** either. Our retreat from leading edge tech is way more frightening than most folk think about.
Ya’ got it SAL. Thanks to LBJ, we couldn’t build a new SR-71 to save our a** either. Our retreat from high tech is frightening on several fronts.
Ya’ got it SAL. Thanks to LBJ, we couldn’t build a new SR-71 to save our a** either. Our retreat from high tech is frightening on several fronts.
Resonance propulsion vibration was commonly referred to a “pogo effect” in the early days of large scale rocketry. You would think that someone at NASA would have remembered about that.
cool story.
looks like Ares 1 is basically a giant guided Bottle-Rocket.
Is this vibration actually an uncontrolled thrust where you get momentary slight bursts of added push up through the rest of the vehicle or are they talking about the regular shake rattle and roll?
Especially when the "moon" pix showed a grassy knoll in the background of one picture.< /s>
Nope. We've lost the recipe. We couldn't easily rebuild a 50 year old design.
If we had the will, we could build it much, much better...
Well in one photo there was a picture of a McDonalds complete with drive-thru on it.
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