Third Stage Design Problem Cause of Most Recent Proton Failure 72
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.
Re:Beautify the world! (Score:4, Interesting)
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.
Redesigned at some point, obviously (Score:5, Interesting)
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.
Re:Redesigned at some point, obviously (Score:5, Interesting)
In the Proton M there is a new upper stage that uses a store-able fuel
There was an effort to move away from 'foreign' parts suppliers, notably Ukrainian
http://en.wikipedia.org/wiki/P... [wikipedia.org]
Re: Redesigned at some point, obviously (Score:5, Interesting)
The real reason behind the switch from Proton-K to Proton-M was that the M one had a digital guidance computer, that could've been programmed by a rookie engineer, while Proton K relied on analog circuits that had to be rebuilt for every trajectory/payload combination.
--Russian vodka engineer
Re: (Score:3, Funny)
It's always Stage III (Score:4, Interesting)
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...
Re:It's always Stage III (Score:5, Interesting)
As light as you can make it, as powerful as you can make it. This leads to fine tolerances and making the design only as strong as it needs to be.
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Yeah and the third stage gets the snot shook out of it by stages one and two before it has to light off. (Don't know if that's actually a problem)
When I was younger I tried running the numbers on stages and for a first stage you can compensate by simply making the thing bigger and you don't pay much of a price. Each stage after that though excess weight cascades exponentially through the design. From memory, an extra pound of weight on the third stage is equivalent to 30 pounds of extra weight on the first
Re:It's always Stage III (Score:5, Interesting)
I think too, not sure, but with the third stage usually you're fully ballistic when it's running. (don't need to fight gravity)
Absolutely right. Play Kerbal Space Program for a few hours, and you really feel this. All your upper-stage engine needs to do is give you enough horizontal velocity to stay in orbit. So you want it to be as efficient as possible, and as weak as possible (since a weak engine is lighter), while still allowing it to finish its burn before you fall back into the atmosphere.
The first stage is quite different. As you said, the first 1g of acceleration it gives you is wasted fighting gravity, so you want the thrust-to-weight to be as high as possible to minimise this fractional loss. On the other hand, go too fast too soon, and you're losing energy to drag. You don't want to go really fast until you're above most of the atmosphere. The mathematical formulation of this is called "Goddard's problem", and the optimum solution is something like: accelerate flat-out until you reach the speed where atmospheric drag becomes significant, then cut your thrust back, and gradually ramp your acceleration back up to max again as the air thins out.
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I think too, not sure, but with the third stage usually you're fully ballistic when it's running. (don't need to fight gravity)
Earth's gravitational field is so vast, it has the Moon in its clutches, you never get so far you don't feel gravity. The term escape velocity much misunderstood, you don't escape Earth's gravity. It means the centripetal acceleration (v/r) is greater than gravitational acceleration. It means the orbit is not a closed curve (ellipse) but an open one (parabola or hyperbola). After some altitude the air resistance falls to near zero and you don't have to fight the drag, that is all. Also the term ballistic co
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Absolutely true. Soyuz too has had tons of third stage failures. It's something that just keeps biting them.
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IIRC, Stage III failures are responsible for a very high percentage of launch failures.
Well, let's see what statistics has to say.
I ignored failures of the payload, non-propulsion systems, or any failures where I could not identify which stage failed. Failures of staging mechanisms were rounded up to the higher stage. Flights with missing stages were still counted. All variants of each rocket family were included - Soyuz includes R7 launches, Thor/Delta includes Japanese licensed derivatives.
Soyuz: 25 first-stage failures, 18 second-stage failures, 29 third-stage failures
Proton: 9 first-stage
Duh! (Score:1)
"I wonder why this problem hadn't been noticed in the decades prior to 2010, when the Proton began to have repeated failures"
They took advice from Microsoft.
Telemetry (Score:2, Interesting)
Improved telemetry and sensors may have helped.
two envelopes (Score:5, Funny)
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.
Re: two envelopes (Score:1)
Or like the current opposition and blame Obama for doing things that Bush actually did and which they supported at the time (like bank bailouts)
Re: (Score:1)
Presidents MUST NOT, and are not authorized to, exist. Your joke only furthers the slavery that is representative democracy. Please report to the fine mesh screen for slurrying.
Design flaw? (Score:1)
Sounds more like a manufacturing/QA flaw to me.
Re:Design flaw? (Score:5, Interesting)
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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Nope. QA makes sure the parts are within engineering specs. It's the engineers job to make sure the design meets the requirements.
Re: (Score:2)
QA also doesn't get to test a lot of complete systems. It's very expensive, and for testing entire rocket systems including the third stage, it's pretty destructive.
Re: (Score:1)
Re: (Score:2)
Isn't that what QA is for?
That depends on whether you have implemented some sort of feedback to engineering from QA. If you start to se some variance in the dimensions (or other parameters) from a manufacturing step, even if these are still within tolerances you can see if there is a correlation to increases in problems in service.
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If it fails while still being inside of tolerances then by definition you need to change your tolerances.
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And that is a design flaw which was my point.
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Because if there's one thing Russia is famous for, it's QA ;)
Re: Design flaw? (Score:4, Interesting)
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.
Re: (Score:2)
It also made them a lot more sensitive to the manufacturer, however. Underfunding a project almost certainly led it to being a disaster (the N1 rocket being a classic example). They generally were willing to sacrifice performance for ease of production and quantity - it was very much a widespread phenomenon.
A friend of mine once served as a translator for the military during one of the late mutual nuclear disarmament treaties (don't remember which one). She described them as pretty much a scam, in that both
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They generally were willing to sacrifice performance for ease of production and quantity
Generally, it is easy to get into situation where a few percent in performance improvement can make your cost double. E.g. current jet fighters, tanks. Or even better example - medical treatments. And at the end its old F-16 or cefalexin that gets the most of the job done.
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Unfortunately, when it comes to rockets, a couple percent difference in performance means a huge difference in the first stage.
The Russians make quite good early-stages for their rockets - but they've long had trouble with the upper stages. The N1 being the glaring exception, even the first stage was big trouble... they just couldn't handle the necessary level of QA for such a complex design to work, at least not on the budget they were given.
The real reason. (Score:2, Informative)
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
Re: (Score:2)
13% of Proton launches (46 of 355) have ended in failure - it's not a very impressive record.
Re: (Score:1)
We Find Design Fault (Score:2)
Re:Is this the same Russian investigation team (Score:4, Insightful)
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.
why none noticed? (Score:2)
Real Life Problem Solving is Hard (Score:2)
Building rockets is hard, finding out exactly why they fail is even harder, especially if it fails in space and all the bits burn up in the atmosphere or stay in orbit around the earth.
Maybe you think that we can send Bruce Willis up with a rag-tag band of hard partying non-professional astronauts to rendevous
CIA did their job? (Score:1)
There is a strong, undeniable evidence, they even put it on YouTube:
https://www.youtube.com/watch?v=REyO1EOOG8Y
Lack of technical expertise (Score:4, Interesting)
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.
Re: (Score:2)
How do we know that? Putin has troops there but gets to deny he has, which is a bit harder to do if he sends in entire regiments. It's a very shitty situation for everyone apart from Putin - he's an evil bastard but he's still getting treated as if he has not invaded Ukraine because of the way it's been done.
The oil price is probably causing a
Because it isn't a design defect. (Score:2)
It was a manufacturing defect that should have been discovered by the most basic of acceptance testing. That this wasn't discovered before the pump was installed indicates they are doing NO quality testing and they are not executing their quality control procedures. Cost cutting corruption, somebody pocketed a thousand dollars at the cost of an entire rocket and payload. And I thought stripping copper out of AC units for scrap was wasteful. Furrfu!
Slapped by The Tail of the Failure Distribution (Score:5, Informative)
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.