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Low Quality Alloy Cause of Shuttle Main Tank Issue
BJ_Covert_Action writes "NASA engineers have finally discovered the root cause of the cracks that have been found on space shuttle Discovery's main external tank. The main tank, one of the 'Super Lightweight Tank' models developed by Lockheed-Martin, employs an aluminum-lithium alloy developed by Lockheed-Martin specifically for this application. The new alloy is used in various structural stringers throughout the SLWT design. Unfortunately, the batch of this alloy used in the tank that is currently mated with the Discovery shuttle appears to be of low quality. The alloy used in the stringers has a 'mottled' appearance, compared to the nominal appearance typically used in the main tank stringers (see picture in article). This appearance is indicative of a fracture threshold that is significantly lower than typical. NASA has determined, through testing, that this low grade alloy has only 65% of the fracture strength of the nominal alloy typically used. NASA engineers have devised a potential fix to the problem that they are currently testing to ensure the repair will cause no unintended consequences. NASA plans to have the Discovery shuttle ready to launch again by February 24th, 2011."
Duct Tape!
In an ideal world, wouldn't the fix be "Pick up the phone, scream at the contractor for trying to pull this shit on you, and demand a part that actually works to spec, right. the. fuck. yesterday."?
It seems like the contract must have been poorly written(and/or a blatant giveaway to our precious, precious defense contractors and their poor starving shareholders) if the solution they are ending up with is "have in-house engineers get their Macguyver on and make the gigantic tank-o'-rocket fuel on a manned vessel work somehow."
Not typical U.S quality. Typical U.S government contracts. Government agencies opt for cheapest price instead of quality usually. I remember when COD4 came out i was working on some contracts for the army and i saw this quote. Could never keep myself from laughing at how true it was. “Never forget that your weapon was made by the lowest bidder.”
The bad alloy is distinct enough from the good one to tell at a glance from a low res photo.
And it even seems that they had records of the unusual appearance. So the materials came in, somebody noticed and documented that this batch looked funny, but nobody thought to investigate if they might have got something other than what was specified?
That this is more of a "make-work" project than anything else. Last shuttle flight is coming up, then everyone goes home. What better way to give them all a 3 month bonus than to find some previously-undiscovered issue.
These aerospace materials are extensively tested, analyzed and inspected. Paperwork with melt number, lot number and names of everyone that ever touched the material are kept.
Decide for yourself...
"Eve of Destruction", it's not just for old hippies anymore...
That's the Government's stupidity for not putting a performance clause into the contract
And you know that because...?
I work as a QA engineer for a large defense contractor. One thing I can tell you is that we issue a lot of documents requiring our plants and our suppliers to follow a metric shitload of MIL, ISO, EN and whatnot standards, for the very purpose of meeting stringent quality requirements set forth in the contracts. It takes months, sometimes years for our products just to pass qualification and type-approval tests, and our products don't even go in space.
In short, you're talking out of your ass.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
False.
Quality has been a part of every government requirement I have ever seen.
Price is another factor as well.
But hey, lets not let facts stand in the way of urban myths and hyperbole.
NASA quality has had a very demanding view on quality. No, it's not perfect. Unfortunately, when it's not perfect and something fails, it's a big deal. When that happens, no one seem to remember all the success.
The singles biggest point of quality failure is no bid contracts.
The Kruger Dunning explains most post on
35% is very high, and it increase the risk enough. Even with perfect materials, there is always a risk.
Clearly you have no clue on engineering shit the goes into and returns from space.
The Kruger Dunning explains most post on
I like how there are folks complaining about NASA when the tank and alloy were manufactured by Lockheed-Martin....
Motorcycles, Robots, Space Gossip and More!
A contractor provides inferior quality alloy for a lightweight fuel tank. So NASA engineers come up with a system to brace said fuel tank, reinforcing it and fixing the problem.
The lightweight fuel tank now weighs as much as a regular fuel tank, when you include the reinforcement, but at 3 times the cost. But don't worry, people stayed employed at your expense, and that's all that matters. Yay!
Seven puppies were harmed during the making of this post.
I am an engineer in the supply side for the nuclear power industry, we have to retrain your kind extensively - our paperwork is measured in avoirdupois kiloshitloads. Good paperwork is no substitute for good quality. The process has to be designed so that it will will consistently deliver the intended product, not merely meet specifications. I would bet that the CMTRs (Certified Material Test Reports) for the batch of stringers that have failures show the material met specs. Meeting specs is what QA is all about, but the right specs and requirements (often supplementary) must to be imposed, and in this case they probably were not. The contractor delivered a defective assembly, and no amount of paperwork is going to change that. One can only speculate on whether there were documents falsified or the process was insufficiently rigorous.
The US government have made it clear that we have no inalienable rights; any we do not defend vigorously will be taken.
I'd have to say that the people who try to bypass the standards and the corporate whores who defend them are the ones talking out of their asses. Then again, you weren't interested in a truthful answer, were you?
Uhh, it's not a ferry boat. Its a fucking space shuttle. The goal is to get into space, not to meet some vague undergrad textbook factor of safety rule of thumb you read as a nooblet. Also, they are not buying bar stock from McMaster-Carr, they're whipping up batches of engineered materials for a specific application. This application is about as performance demanding as things get, the runs are small, the costs are high, and there is not a lot of room for error. Yet man is still not god, so errors happen despite the best efforts of a lot of dedicated people. If you are a real engineer, and you have never made a mistake, then count your blessings instead of acting like a cock. If you're not a real engineer then STFU.