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Ammonia Leak Alarm On the ISS Forces Evacuation of US Side: Crew Safe
New submitter BabelBuilder writes: An alarm signaling a possible ammonia leak aboard the ISS this morning caused the crew to evacuate the U.S. side of the station. All crew aboard the station are safe. "Flight controllers in Mission Control at NASA's Johnson Space Center in Houston saw an increase in pressure in the station's water loop for thermal control system B then later saw a cabin pressure increase that could be indicative of an ammonia leak in the worst case scenario. Acting conservatively to protect for the worst case scenario, the crew was directed to isolate themselves in the Russian segment while the teams are evaluating the situation." They don't yet know whether it was caused by a faulty sensor, a problem in the relay box, or another malfunction.
...with no electrical or electronic component to their basic functionality. I find I can confirm false-readings much more easily than relying on an electronic sensor, and that it seems like at least with automobiles, the sensors themselves fail more often than the conditions that the sensors were designed to detect actually manifest.
Do not look into laser with remaining eye.
When did the Iron Curtain between Russia and U.S. went up on the International Space Station?
Roger, Houston, we have another "ammonia leak."
Requesting that you please stop sending up the freeze-dried chili in the supply missions, at least while Jim is on station.
SJW's don't eliminate discrimination. They just expropriate it for themselves.
I'm a trifle surprised that the ISS would be using ammonia in its refrigeration system. I understand that it is a common terrestrial choice(though mostly in industrial systems, not home use equipment, even if well sealed) because it's pretty good at being a refrigerant and dirt cheap; but it's not a terribly pleasant chemical. Not death on a stick or anything; but an gas that readily dissolves in water to form an alkaline solution potentially strong enough to be a tissue damage risk(good thing that only unimportant stuff like our eyes and lungs are naturally moist, right?).
Given that anything lofted into orbit automatically costs some thousands of dollars a kilogram, I would have expected a slightly more price-insensitive choice, probably one of the fancier halogenated hydrocarbons, or a mixture of them.
Does anyone know why ammonia was used instead? Is it that a leak would be dangerous even if the refrigerant were 'the warm fragrance of a spring day'; because of the life-critical nature of the refrigeration system and the relatively tiny volume of breathable atmosphere aboard the station, making using a less noxious refrigerant little more than a way of avoiding alkali burns and asphyxiating or overheating instead? Is ammonia sufficiently superior(per unit mass, volume, or both) that it would be heroically more expensive to ship a different refrigerant into orbit? Some other factor I'm not considering?
American components, Russian components... all made in Taiwan!
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
"I would recommend that we put the unit back in operation and let it fail."
On the russian side they use blue electrical tape, not duct tape.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
Also, it will allow dramatically hopeful crew to tap the gauges as they edge towards criticality...
I emailed a friend who worked on Station's ECLSS back in the 90's, and this was his reply:
"Ammonia has a great specific heat (ability to carry the thermal load), plus its boiling and freezing points work really well in space applications. It's also (aside from toxicity) a very well-known, simple, cheap and fairly easy material to work with. The way the TCS loops work on ISS, the ammonia loop is external; it never mixes with the internal (water) loops. There are external heat exchangers to pass the thermal loads from inside to outside; the water loops out of the pressure vessels through the end cones to the heat exchangers and back inside. The only way for ammonia to get into the water loop (it seems to me) would be a debris strike or something like that in a heat exchanger (and they're protected by MMOD shielding, as well as being rather out of the way)."