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Minor Technical Issue Aboard Shuttle Discovery
IZ Reloaded writes "Space Shuttle Discovery has a problem with the pipeline for an auxiliary power unit that controls the shuttle's hydraulic steering and braking maneuvers. CNN reports that the pipleline is leaking 'fuel' at about six drops per hour." From the article: "The leak is more likely nitrogen, but there is no way of knowing that, so NASA is treating the problem as if the leak were fuel ... If it is fuel, the current rate is still 100,000 times slower than what would cause a fire ... Just in case, NASA will turn on the power unit with the leak early Sunday as part of its normal testing and then see if the leak rate changes. If it does, NASA may burn off the hydrazine and shut down the power unit before the shuttle returns to Earth to eliminate any fire hazard.'"
There are pipelines in space now? Cool.
The leak is more likely nitrogen, but there is no way of knowing that.
Excuse me? The shuttle must be one of the most redundantly-instrumented efforts ever built and they don't know what's leaking?
Hydrazine is nasty stuff but it is just one of the dangerous checmicals aboard the shuttle.
When Columbia broke up, it was the possible presence of Hydrazine from the APUs that make the Texas Dept of Health issue warnings about approaching shuttle debris.
The problem with spaceflight is that everything is so close to the edge. Performance requirements that can still leave a good safety margin mean that simpler and safer methods are often inadequate. Consumers don't have the same risk/reward ratio as people who sit on top of rockets for a living.
-M
# grep slashdot access.log | grep html | sort | uniq | wc -l 2604
Mod parent up: both informative and insightful.
I don't know how NASA can spin this as a minor issue. This is about as bad as a missing heat-protecting tile.
"but in my experience leaks tend to get worse.."
You are an experienced astronaught?
The shuttle has 3 auxillary power units. One is necessary to land. They are routinely tested while in space. If one fails they land as soon as possible. The APUs are not small, they are powered by a 100 horsepower turbine which is turned by decomposing hydrazine over a catalyst. Sometimes on good movies of the shuttle after it has landed you can see the heat waves from the hot gases (nitrogen, hydrogen, and a little ammonia) from the decomposing hydrazine coming straight up from the shuttle.
The larger thrusters and the rocket engine used by the shuttle in space are powered by methyl hydrazine reacting with nitrogen dioxide. These are hypergolic (burn on contact with each other) so no possiblity of them failing to ignite for a second or two then going boom which is possible with other fuels like hydrogen and oxygen. They are liquids at ambient temperatures so don't require cryogenic storage.
Hydrazine, N2H4, is a great rocket fuel. It is a liquid with similar boiling and freezing points to water -- but can explosively decompose (it is dangerous to measure its boiling point), is toxic at ppm levels, is carcinogenic (ie all the rats that breathed it got nasal cancer), causes skin burns. Like most amines it smells like rotten fish. Believe it or not there are people who believe that low levels in the blood is an anti cancer agent.