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1. Wanna hear a weird but true story? (I have a few minutes to type, so here goes). I almost lost my hearing from the lid on the tank of a toilet. Noise-Induced Hearing Loss. You wouldn't think a toilet lid could be so loud, would you? Well, I learned otherwise...
2. I was fixing the mechanism inside the tank of the toilet. The only thing left to do was to put the ceramic lid back on the tank. Unfortunately it slipped out of my hands and banged on the ceramic of the toilet rim. Again, you wouldn't think that would be so loud, would you?
3. Well, the sound stunned me. I stumbled out of the bathroom and fell to my knees in the living room, wondering what had just happened. Did something happen, or did I imagine it? It was surreal. Then I got the idea to test my hearing, because I noticed something seemed weird.
I looked into it and was told the last surviving Lunar Module telemetry tapes were stored in a missile silo and were old so the magnetic material was coming off. To read them we’d need to develop a procedure to bake the tapes, re-adhere the material. Then...1/n
2/n then we could play them back, but the last surviving tape player for that type of tape was in Langely, Virginia, so we’d need to ship them there and send funding. Then after reading the data we’d need to figure out what data formats the Lunar Module was using...
3/n. A data format is how the vehicle selects which of the thousands of possible measurements it could send back to Earth in any particular period of the mission. Data formats are all defined in this documents we would need to track down...
Another story on forgotten requirements in the space program. During NASA’s Constellation program, we all knew the Apollo Lunar Modules had a requirement that they couldn’t land on terrain more sloped than 11 degrees. (Or was it 10.5? I’m no longer sure.) But nobody knew why. 1/n
2/n Even the lead designer for the Altair lunar lander told me that he didn’t know why Apollo Lunar Landers had that requirement, although he knew that it was in fact their requirement. It was another requirement whose rationale was long lost in the mists of time.
3/n One reason we talked a lot about that requirement was because it almost got violated during one of the Moon landings: Apollo 15. That mission, lunar module blew so much more dust than most other landings (except Apollo 12) that they couldn’t see what was beneath them.
Strange but true story: the giant round propellant tanks at the Apollo/Space Shuttle launch pads were certified to be emptied & refilled only 6 times. Nobody could remember why the number of refills was limited, but they were dutifully kept full of liquid oxygen for 40 years. 1/n
2/n. Nobody knew where the requirement originally came from, way back in the 1960’s. Was it a structural limit, the steel would get too weak if warmed then re-chilled to liquid oxygen temp more than 6 times? Nobody still living knew.
3/n The requirement itself was documented since the 1960s, but the reason behind the requirement was as lost as ancient texts in the Library of Alexandria. So we dutifully obeyed for DECADES keeping those tanks full without ever knowing why.