Could a Dirty Rag Take Out a $2 Billion Satellite? 297
An anonymous reader writes "The alleged rescue of a U.S. military communications satellite underscores some of the weaknesses in U.S. space efforts. Quoting: 'The seven-ton “AEHF-1,” part of a planned six-satellite constellation meant to support radio communication between far-flung U.S. military units, had been in orbit just one day when the problems began. The satellite started out in a highly-elliptical, temporary orbit. The plan was to use the spacecraft’s on-board engine to boost it to a permanent, geo-stationary orbit. But when the Air Force space operators at Los Angeles Air Force Base activated the engine, nothing happened. The Government Accountability Office would later blame the failure on a rag left inside a fuel line by a Lockheed worker.'"
Hmm...scale does not compute. (Score:5, Interesting)
Must be a really small rag or really big fuel line. Seriously, how would this happen? It's a freaking satellite engine, not the shuttle main.
The answer appears to be a yes. (Score:5, Interesting)
And yes, I went with the car analogy right from the start. Deal with it.
Test Sequence? (Score:4, Interesting)
Who puts an engine together without a test fire? Seems to me that some simple checks would have prevented a very big waste of funds and effort. I guess it won't be a total waste if they can learn from it.
Re:The answer appears to be a yes. (Score:4, Interesting)
Exactly! Any old blockage could prevent fuel from getting through the fuel line. Same with the oxidizer. Even smashing a bug under an electrical component could cause a failure.
Foreign object debris seems to be common... (Score:5, Interesting)
At least one of the recent Soyuz failures was put down to a similar issue - debris left in a fuel line by a worker.
Re:Lots of failures there. (Score:5, Interesting)
It reminds me of those surgery horror stories where the surgeon or staff leaves behind clamps and sponges inside the persons body.
Shit happens. All we can really do is our very best to try and prevent it, but ultimately, we're human and prone to mistakes.
Re:Lots of failures there. (Score:5, Interesting)
Actually pre-flight final won't catch that kind of thing; it's already buried in the system (and you don't fire thrusters on a flight unit prior to launch). This is likely one of those cases where a scrap of cleaning"rag" was torn off within the path in an area not visible at either end and went unnoticed. To save money, a visual of the system prior to final assembly was determined to be sufficient and the endoscope procedure was eliminated, saving several thousand dollars (combined on all the lines). Sure, in hindsight a compressed air test would have been sufficient, but it's a little late to play what-if now.
Re:Lots of failures there. (Score:5, Interesting)
> It reminds me of those surgery horror stories where the surgeon or staff leaves behind clamps and sponges inside the persons body.
Funny you should mention that. I had emergency surgery last year for severe traumatic internal bleeding (won't bore you with the details -- or maybe I already have) and things happened so quickly that they did not have enough time for an instrument inventory. (Apparently it's someone's job to keep track of how many tools get used and then count them before final suture.) So after they got me stable they ran me back through x-ray to look for stuff. Didn't find anything, fortunately.
But really -- it's not that much of a horror story, they just have to open you back up at some point to retrieve the objects. It's not something you want to have happen, but it's a fairly well known procedure. Horror stories to me are things like taking off the wrong limb [1] or prescribing catastrophically wrong medication.
[1] Before I went in for knee surgery, the doctor gave me a sharpie and had me mark the correct knee. Just in case.
Re:Hmm...scale does not compute. (Score:5, Interesting)
You can use tiny squares of cloth, impregnated with cleaning solution, to clean the inside of valves and metal lines - gets rid of metal filings which are left over from the boring process.
Quite easy to leave one behind. Which is why there are processes in place designed to prevent such issues.
So, they built a tool to make sure the rag was removed. Then they built another tool to check that the first tool was removed...
More seriously, why wouldn't groundside testing notice that there was a rag in the line?
Re:Hmm...scale does not compute. (Score:4, Interesting)
Catching every little thing that might gum up the fuel lines during assembly, testing, and cleaning seems like it could be a genuinely hard problem. Doing a combination pressure test/gas flush seems like it would be a cheap, simple, brute-force solution to that entire class of potential problems...