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Third Stage Design Problem Cause of Most Recent Proton Failure
schwit1 writes: The Russian investigation into the latest Proton rocket failure has concluded that the failure was caused by a design failure in the rocket's third stage. The steering third stage engine failed due to excessive vibration as a result of an imbalance in a rotor of a pump unit.
While it is always possible for new design issues to be discovered, I wonder why this problem hadn't been noticed in the decades prior to 2010, when the Proton began to have repeated failures.
The Proton rocket has gone through a number of redesigns over its long life. The latest version, the Proton-M, first flew in 2001, and they kept flying the Proton-K for many years (for reasons I actually don't know). They've only done 90 flights of the Proton-M, and half of them were in that post-2010 period of "repeated failures" (although they had about as many failures for pretty much all of the 2000s as well).
I would highly expect the faulty pump to have been redesigned with the Proton-M modifications, based simply on that analysis.
Improved telemetry and sensors may have helped.
So I read that this problem dates back to 1988 (so they say). Reminds me of a two envelope joke. A president steps down due to scandals, gives his replacement 2 envelopes. Tells him to open the first one when there is the first serious problem he cannot handle and the second one in case of another problem.
The replacement starts on the job, eventually there is a serious political problem he cannot solve. He opens the first envelope and it says: blame everything on the previous guy. So he does and the problem goes away. Later there is another problem that cannot be solved, the guy opens the second envelope and in says: prepare 2 envelopes.
I think somebody opened the first envelope.
You can't handle the truth.
The Proton series once had a world record for the longest uninterrupted series of succesful launches.
The real reason behind the switch from Proton-K to Proton-M was that the M one had a digital guidance computer, and they were able to find peope to program them, while the K modification had analog computer that had to be rebuilt for every payload.
--Russian vodka engineer
The Proton rocket has gone through a number of redesigns over its long life. The latest version, the Proton-M, first flew in 2001, and they kept flying the Proton-K for many years (for reasons I actually don't know). They've only done 90 flights of the Proton-M, and half of them were in that post-2010 period of "repeated failures" (although they had about as many failures for pretty much all of the 2000s as well).
I would highly expect the faulty pump to have been redesigned with the Proton-M modifications, based simply on that analysis.
IIRC, Stage III failures are responsible for a very high percentage of launch failures.
Although IIRC, Clancy once wrote about one being faked in order to put a spy satellite into orbit without people realizing it was a spy satellite. Of course, the tech wasn't as good then...
Continually lying to the world eventually gets the world to see you as a habitual lier. Putin can rig Russia to stifle dissent but not the world.
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With Russia's invasion of Ukraine not going quite as planned, and Russia now building up another invasion force on its border with Ukraine, the trained specialists who would have caught this error have been rerouted to help produce more advanced rockets for the military.
The problem is the sanctions imposed on Russia for its invasion are hurting its ability to pay its people. Some have gone as long as four months without pay and even when they are paid, it's not the full amount. Since there is no money to be made working on their space program, these people go to the military side which Putin continues to pour money into while grocery shelves start to go bare around the country.
Expect to see more such accidents until Russian troops are out of Ukraine and there is cooperation with the West who can provide technical guidance in these matters.
We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
Not necessarily. I am a Mechanical Engineer and I work in a machine shop. Every part you design has tolerances on every dimension. But if you work with machinists with lots of pride like I do they will tend to try to hit the tightest tolerance they can just to keep up good practice and produce nice parts. So I can have a design that when I send it to my shop works flawlessly. But if I send the same drawings to an outside shop and they take full advantage of the tolerances I allowed I might be in for a surprise.
The same could be true here. The design worked because one shop produced parts that exceeded the specifications but might fail for a certain combination of tolerances that are still within the allowed design.
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I saw Third Stage Design Problem open for Flaming Reentry in Kalamazoo, MI in '87.
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Maybe it is time to sterilize racist bigots, and Anonymous Cowards.
Until then, maybe it's time /. added a block on Anonymous Cowards for the first 2-3 hours after a post is published, or has at least 100 messages.
The reasons why this flaw was not identified previously was because it was a low probability occurrence. The shaft was just barely adequate to survive most of the launches, but sometimes it failed before engine cutoff. Since the debris is hard to access, gathering evidence that this was indeed the culprit was very difficult, especially when they didn't know what to look for. The engineers got some hints from previous failures that caused them to put vibration sensors in an area of the rocket that allowed them to identify the current failure mechanism.
This is a problem in rocket design where you have two opposing constraints - they need a pump that works reliably all the way to orbit, but since the rocket is disposable and extra mass reduces payload, overbuilding the pump is not ideal either. This pushes one toward a design that is just barely good enough and no better. It turns out that they wanted a pump that would work for 99.9% of the flights, but they got one that worked 86% of the flights instead.
This was actually a pretty challenging problem in engineering forensics. I hope this fixes their issue. The Proton is a pretty solid rocket otherwise.
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To be fair, the Soviets made some amazing equipment during the cold war. The Americans for example were amazed by the NK-33 rocket engine. One of Lockheed's engineers described how they couldn't have made a similar engine in the US because of design concepts. Russian design engineers gave the design to the manufacturing engineers who in turn would refine the design during manufacturing. The design was then built, tested and refined iteratively. American engineers were less likely to build a design that was likely to fail - the design had to be refined before it was built which meant that they were more likely to be conservative.
UK's Channel 4 had a series called Equinox that did an episode on it.