Slashdot Mirror
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.
What seems more amazing is that a simple software check pre-launch (i.e. "do all the sensors think they are pointed up?") was not part of the SOP. Given that their exact function is orientation detection, skipping the opportunity for self-test via that function is somewhat baffling.
Obligatory: It's not rocket science!
The greatest pleasure my toddler ever got from his shape sorter was when he discovered that the 3 could be forced through the hole for the C. Never underestimate the satisfaction a disgruntled office worker gets from jamming the ink block into the printer the wrong way around.
My reading of 'angular velocity sensor' is that they're meant to sense rotation. If you're sat stationary on the pad there is no such rotation and thus you'll get a 'correct' zero reading. You'd have to perform such a test during some known movements of the rocket (part).
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.
Communism (n) - an unattainable standard that is constantly held up as a model of perfection despite having no functional real world example past or present.
Sorry, but that's nonsense. All you need to do to create perfect communism is kill everyone else so no-one can disagree with you (you can't just kill the ones who disagree, because the others might only be pretending to agree).
Stalin made a pretty good attempt, but didn't quite succeed.
>That would be like saying that disaster relief volunteers are an example of communism
Actually that sounds about right to me. "From each according to their ability, to each according to their need" and all that.
Most family households also run on at least partially communist principles. Luxuries may need to be at least partially earned (or not, plenty of douches with entitlement issues out there), but it's a sad family where everyone's *needs* aren't taken care of first.
The problem with communism seems to be that it doesn't seem to scale well beyond the tribe/monastery/commune level. Once the population gets too large to allow for effective communal decision making, communal ownership tends to become de-facto ownership by the decision makers, massively exacerbating the problem of corruption.
--- Most topics have many sides worth arguing, allow me to take one opposite you.