Design of Next-Gen NASA Rocket Showing Flaws

caffiend666 writes "According to an AP news article, NASA engineers are concerned about the design for the new rocket meant to replace the shuttle. Work on the project has revealed that the first few minutes of flight could see 'violent shaking', a serious flaw that might destroy the craft soon after launch. '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. 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.'

Comments

Better to find it now rather than later...

[the_humeister]

...before it's built. Seems like a non-story.

Re:Better to find it now rather than later...

[khallow]

I disagree. This problem would have been obvious from the start. I simply don't understand how they got so far without addressing it. Sure, they wouldn't have known the full dynamical details of the SRB vibration, but they would know the crude resonance modes of the rocket and that the SRB kicked out vibration in these frequencies. Hence, they would have known at the very start that this was a problem. So why wait at least two years (until right after the Ares 1 supposedly passed its "system requirements review") before you start thinking about this problem? My take is that they put off discussion of it as long as they could. As I see it, the next year is critical not just to Ares 1 development, but to the entire VSE plan. If they haven't resolved the basic design problems with both the Ares 1 and the CEV (and yes, I think there are serious issues to be resolved here), then we might not see any of this survive the next administration.

so what?

[The_Rook]

so they found a problem with a preliminary design. big deal. that's why they call it research and development.

how long did it take to design the saturn Ib/saturn V and make sure that they'd mate well with the apollo capsule? how long did it take to come up with skylab, an orbiting lab that could be mounted on a saturn V?

i expect it'll take about five to six years to bring the orion program to a complete first generation system.

Re:so what?

[Pedrito]

Mod parent up. This is a completely ridiculous article. It's little more than a footnote on a status update of the development.

Re:so what?

[cyclone96]

Indeed. In fact, the Saturn V itself had problems with pogo oscillation, a condition that affects liquid fueled rockets and caused the center engine shutdown during the first stage of Apollo 13.

Re:so what?

[Antique Geekmeister]

Mercury started launched amazingly shortly after Sputnik, in 1957 or so. Gemini launched in 1963, Saturn launched in 1967. That gives less than 10 years to build 3 generations of spacecraft and launch the third generation, successfully.

NASA has known that the Space Shuttle flies like a duck-taped cow since well before its first launch in 1981, since it was designed by committees lobbying wildly to have different components manufactured in different states to get Congressional approval and for many other political, rather than engineering, reasons. Development of replacement spacecraft has been hindered by funding, similar lobbying stupidity, and the unwillingness to admit that rockets have to be built and tested rather than modeled to death for decades before actually trying anything.

Private industry has already shown a far more capable design, when the Ariadne won the X-Prize. But NASA is blocking its development for numerous political reasons, not engineering reasons. You cannot expect NASA to do anything in real development and admit that complex craft are going to crash in the design and testing phase, and treats it as an acceptable risk rather than a political nightmare. And their current leadership is too politically hidebound to do anything profoundly innovative: it would interfere with the "5 year plans" of their contracts with Boeing and other manufacturers.

Holy cow!

[ruiner13]

You mean they didn't get the design of a prototype exactly right on the first try? Amateurs! Seriously though, where is the news here?

Nasa: Delay if Necessary

[quanticle]

If anyone else has read Diane Vaughan's Challenger Launch Decision, he or she will know that launch schedule pressure from upper management was a leading cause of the rationalization of risk that NASA undertook to justify flying with known Shuttle desgign flaws. Hopefully, in this case, the NASA senior managers are not applying the same mindless schedule pressures that leads to quick fixes and mindless workarounds at the expense of long term safety.

Re:Solid Rocket Boosters

[segedunum]

Solid Rocket Boosters are sort of like strapping yourself to a firecracker. We can't have liquid ones?

You could have liquid ones, but they take an awful lot of development to get right. NASA, and US institutions in general, typically don't like them because of the danger involved (the Soviets have had some major disasters with liquid fuels). The only people who really did get liquid fuels to be fairly safe and reliable were the British and their Blue Streak (HTP was used after the failure of LOX - impractical in an ICBM), Black Arrow and Black Knight projects:

http://en.wikipedia.org/wiki/Blue_streak
http://en.wikipedia.org/wiki/Black_Arrow

These rockets were a departure from everything else around, and used Hydrogen Peroxide as an oxidiser - cheap, readily available and works well at normal temperatures and pressure. Most considered the fuel to be too hazardous, and a Hydrogen Peroxide fuelled torpedo allegedly sank the Kursk (probably not sensible on a submarine), but the British developed ways to handle it safely and efficiently. To this day, no one else has tried this method and its pretty advanced rocketry even forty years on. It certainly gets rid of the dangerous handling of liquid oxygen, which has to be kept ultra cool and under controlled cryogenic conditions.

After a textbook final launch, the project was cancelled. Given the need for commercial satellite launches over the past few decades, the mind boggles as to how cheap and useful this could have been if developed further. The British, as per usual, decided that simply reusing the Scout solid fuelled rocket would be cheaper. Go figure.

Re:Solid Rocket Boosters

[rijrunner]

LOX is routinely handled by thousands of industrial facilities in the US alone. Its properties are well known and it has been used safely for over a century.

    Liquid boosters have been used safely on dozens of rocket types. They have been used safely to launch crewed capsules. Liquid rocket engines are commercially available. (In fact, every single crewed American vehicle has had liquid fuels as their main source of energy. The SRB's on the Shuttle are booster assist and the only Gemini to fly on a solid was an unmanned test capsule).

    What we are seeing here is a departure from decades of development. Solids have been considered unsafe for manned flight for decades as they are not able to be throttled in flight. Once lit, they burn to exhaustion. They have uneven burn characteristics due to uneven mixing of the propellants. No solid casing has ever been put in a load of this magnitude. (The SRB's on the Shuttle never carried the full weight of the shuttle and they were axially loaded as opposed to have the load directly along the case). There is no engine shutdown in an SRB.

  Arguing that liquids would take a lot of development to get right is a bit misleading as it is just as much a statement to be made for SRB's.

  The whole Shuttle-derived stuff is crap. These are essentially new engines along with a new booster design and they should have had a design competition and weigh the relative merits of various design proposals. This was a fiat decision made by Griffin when he came into office. There was no technical justification. No weighing of options. Even the sizing of the Orion is extremely questionable.