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.

Comments

Re:QA is not the problem

[TheCarp]

Amusingly, when someone actually attempted to track down who murphy was, and where the law came from.... http://en.wikipedia.org/wiki/Murphys_law

Edward Murphy proposed using electronic strain gauges attached to the restraining clamps of Stapp's harness to measure the force exerted on them by his rapid deceleration. Murphy was engaged in supporting similar research using high speed centrifuges to generate g-forces. Murphy's assistant wired the harness, and a trial was run using a chimpanzee.

The sensors provided a zero reading; however, it became apparent that they had been installed incorrectly, with each sensor wired backwards. It was at this point that a disgusted Murphy made his pronouncement

So this is potentially, very much related to the original usage.

Re:The quality conrol problems...

[PetiePooo]

...aren't so amazing when you look at the track record of Russian manufacturing.

Before we Americans point too many fingers, let's not forget NASA is not immune to similar mistakes.

Re:(The Real) Murphy's Law strikes again!

[PetiePooo]

My favorite is Cole's Law...

Re:QA is not the problem

[Baloroth]

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 sensors in question were for angular velocity. Given that pre-launch the craft doesn't have any (peculiar) angular velocity, the sensors would return the correct results (zero) no matter how they were installed.