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Upside-Down Sensors Caused Proton-M Rocket Crash
Michi writes "According to Anatoly Zak, the crash of the Russion Proton rocket on 1 July was apparently caused by several angular velocity sensors having been installed upside down. From the source: 'Each of those sensors had an arrow that was supposed to point toward the top of the vehicle, however multiple sensors on the failed rocket were pointing downward instead.' It seems amazing that something as fundamental as this was not caught during quality control. Even more amazing is that the design of the sensors permits them to be installed in the wrong orientation in the first place. Even the simplest of mechanical interlocks (such as a notch at one end that must be matched with a corresponding projection) could have prevented the accident."
A review of the quality control procedures used by the contractors responsible is underway.
...aren't so amazing when you look at the track record of Russian manufacturing.
being from there i bet half the people working on this came to work drunk and/or hung over most days
Murphy's Law is still in effect. Like the snippet says make sure that they can only be installed one way mechanically, because you won't catch 100% of the errors in QA.
Wasn't something like this responsible for the formulation of Murphy's law?
Hey, give them a break! I do that in Kerbal Space Program all the time!
Should have launched from Australia.
which plowed into the desert floor without deploying any parachutes because a G-switch was installed backwards...
http://www.universetoday.com/73/genesis-accident-report-released/
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Perhaps the thinking is, as long as the arrow isnt pointed at you it's probably safe.
"Whoopth, I had the thilly thing in reverthe!"
I am officially gone from
In the postmortem the flight director started with, "... we sadly lost the vehicle after a flight of 1.5 seconds ...". The mission director interrupted, "What flight? The damned thing had a 6000 Kg[sic][*] rocket booster. You can put it under a 3 ton rock and it will 'fly' for more than 2 seconds..."
[*]He should have said 6000 Kgf-sec, because that was the impulse delivered by the twin rocket boosters each 1500 Kgf thrust burning for 2 seconds.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
The US once sent a probe all the way to mars, only to have it fail because the ground computer was in imperial units while the orbiter was in SI units.
Getting everything correct is hard... really hard. For most projects you have elaborate "fail gracefully" modes which rely on external agents to notice the problem and take action. A doctor or pilot can take appropriate action, but it's hard to do with rockets.
For comparison, I wrote the software for the altimeter that goes into some 747 aircraft. Total of about 21,000 lines of C, about 40% comments so figure 12,000 lines of code. The testers (and I) worked really hard to find all bugs in the system, knowing that a mistake could knock a plane out of the sky. There were elaborate internal checks both in software and process, and Boeing did their own testing on top of ours. Everything passed, all requirements were met, things looked good.
The device had 1 bug, found after installation. A software typo which wasn't caught by QA even though it had a specific testing requirement. No one was negligent, it just slipped by despite best efforts.
Multiply this by all the devices in an aircraft, and add in the other engineering disciplines like electronics and mechanical. It's really hard to get everything right all at once, and on the first try.
I'm confused by this explanation. An upside-down angular velocity sensor would definitely pitch the rocket out of control the way it did. But what about the brown plume that was clearly visible before the rocket lost it? The consensus seemed to be that that was unburned rocket fuel, implying an engine shutdown.
I don't build rockets, but I can't see how an upside-down rotation sensor could cause an engine shutdown, especially since the shutdown occurred before the rocket began pitching.. Could there have been more than one problem on the rocket?
Everything is better with chainsaws.
In Soviet Russia, snesors installed correctly, rocket installed upside down.
Silence is a state of mime.
If you want to go to space.
If it starts pointing toward space you are having a bad problem and you will not go to space today.
Can the flight control system verify the sensor readings before launch? "Sensor 7 says the rocket is pointing towards the Earth on the launchpad - we might want to have a look".
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Yeah, weak joke, sorry.
Mostly random stuff.
The short answer is "yes".
All functions range-checked their arguments on entry, calculations range-checked their results before performing further calculations, precondition logic was tested to ensure the preconditions held, periodic testing checked as many "things that should never happen" as we could think of.
We never ignored a possibility because it was absurd, so long as there was a way to test it it was tested. The difficulty is coming up with a comprehensive list of things to check... very hard to do in practice.
The Russians are using contractors, now?
On the other hand, they seem to be doing vastly better than the US these days - we have NO WAY to put someone in orbit (unless the Pentagon's got a black program).
We also had Challenger and Columbia. And on the latter note, I'll add that I believe my late ex's analysis, rather than the "it's falling insulation" answer. She was an engineer, and worked at the Cape for 17 years, including on the Shuttle, and she thought that some of the inspections that were supposed to be done were *not* being done, or not being done as frequently as they were supposed to have been... and that the hydraulic lines broke due to stress corrosion microcracking, and there went the aerilons.
So, how many astronauts/cosmonauts have the Russians lost lately?
mark
Not correct. If you cannot accurately sense this rate (~15 deg/hr) you will go far off the trajectory in a 10-15 minute boost. It absolutely cannot tolerate errors of a few degrees. Checking for the proper rates is an absolutely standard pre-launch check and typically, any biases in this are calibrated out while on the pad based on the known alignment of the rocket and the lat/long of the pad.
You wouldn't need a notch, you simply move the screw holes around so they aren't square. The best method is a trapezoid pattern. Two screw holes are set closer together. Impossible to mount upside down or sideways. Or simply shift one screw hole like the ATX power supplies do.
And the K19.
And the K141 (The Kursk)
Soyuz 1
Soyuz 11
And about half a dozen other fatal accidents involving shoddy workmanship.
Chas - The one, the only.
THANK GOD!!!
You'd think the Russians would study other industries lessons learned and best practices.
Have gnu, will travel.