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No radiation hardening. Their main priority was building a system in 7 months that meet their toxicity and flammability standards. The original military telepri

by kens 2y ago

No radiation hardening. Their main priority was building a system in 7 months that meet their toxicity and flammability standards. The original military teleprinter weighed 100 pounds. They cut it down to 59 pounds, so that's a win, I guess.

crazygringo 2y ago
Were commercially available dot-matrix or daisy-wheel printers toxic or flammable? My initial thought was also that this was for radiation hardening. But if not, I still don't understand at all why they didn't buy something lighter and cheaper off the shelf. Do you know specifically what component(s) didn't meet the toxicity and flammability requirements? And why any specific components like that couldn't just be swapped out, rather than redesigning the entire thing?
- colechristensen 2y ago
  Vibration is a big deal in space. Launches aren’t gentle. Think “repeatedly thrown down a flight of stairs” toughness is required. And it’s a closed atmosphere so any amount of outgassing is paid close attention.
- deleted 2y ago
  [deleted]
- jcrawfordor 2y ago
  Most plastics of the era would not meet requirements for aviation fire safety, they produce toxic smoke when burning (still a significant problem today). There's an obvious tension between "reduced weight" and "not using plastics," but that was kind of the deal in aviation technology at the time. Aviation equipment is still pretty chunky today, because of the materials needed for low/no smoke evolution and vibration tolerance. Considering it probably also had to meet a MIL-STD environmental spec, stripping a commercial printer and putting it in some kind of aftermarket metal chassis seems like a much more expensive/higher risk route than using something that was already made to those standards. Environmental specs, in this context, usually mean min and max operating temperatures and acceptance of vibration and shock, within certain G-force and frequency measurements, with "without malfunction" and "without damage" thresholds. Aviation and military equipment have to go to environmental testing laboratories to be certified to these requirements, which can be a considerable expense on its own, and another reason it's smart to use an existing design. Besides, the military already made use of teleprinters in aircraft and so there was operating experience to build confidence. The space shuttle model is based on the family made by MITE, which included airborne variants used on bombers for example.
  - throw0101c 2y ago
    > […] and vibration tolerance. Never thought of this before, but rocket launches are quite the event. Doing a quick search, see perhaps ISO 10816: * https://acoem.us/blog/other-topics/understanding-the-iso-10816-3-vibration-severity-chart/ https://acoem.us/blog/other-topics/understanding-the-iso-108... Amongst others: * https://vibrationresearch.com/blog/understanding-nasa-std-7001-test-parameters/ https://vibrationresearch.com/blog/understanding-nasa-std-70... * https://vibrationresearch.com/testing-standards/ https://vibrationresearch.com/testing-standards/ * https://www.avmc.army.mil/Portals/51/Documents/TechData%20PDF/ADS27ASP.pdf https://www.avmc.army.mil/Portals/51/Documents/TechData%20PD...
- shadowpho 2y ago
  >Were commercially available dot-matrix or daisy-wheel printers toxic or flammable? It’s not a binary but spectrum. For example military has a long list of standards for wires. The ships/tanks/planes use different wiring than your house does. That doesn’t mean our wires are toxic and flammable but they are probably more toxic/flammable than the application calls for. And here is the problem: there was no off the shelf printer that met their exact requirements on paper. It’s possible some of the printers were similar quality but they were not certified to same standard. So NASA would call a printer company and ask “does your printer self extinguish? What about in 100% oxygen? What about inrush current? Does the motor stall and what are the protections?”. The printer company would not want to spend the time/energy on that vs what nasa would be willing to pay for 5-10 printers.
  - ahoka 2y ago
    “The printer company would not want to spend the time/energy on that vs what nasa would be willing to pay for 5-10 printers.” Epson did a bit more than a decade later.
- akira2501 2y ago
  There were several classified shuttle missions. In those missions their link capacity was severely degraded and had to run through encrypted military rather than open NASA civilian channels. This became an issue on STS-27 where they were unable to inspect tile damage with high resolution imaging because of these limitations. The astronauts on this mission were not at all pleased with the situation, and they had good reason not to be, as an entire tile had become dislodged by foam during the ascent.

by kens 2y ago

crazygringo 2y ago

Were commercially available dot-matrix or daisy-wheel printers toxic or flammable? My initial thought was also that this was for radiation hardening. But if not, I still don't understand at all why they didn't buy something lighter and cheaper off the shelf. Do you know specifically what component(s) didn't meet the toxicity and flammability requirements? And why any specific components like that couldn't just be swapped out, rather than redesigning the entire thing?

colechristensen 2y ago
Vibration is a big deal in space. Launches aren’t gentle. Think “repeatedly thrown down a flight of stairs” toughness is required. And it’s a closed atmosphere so any amount of outgassing is paid close attention.
deleted 2y ago
[deleted]
jcrawfordor 2y ago
Most plastics of the era would not meet requirements for aviation fire safety, they produce toxic smoke when burning (still a significant problem today). There's an obvious tension between "reduced weight" and "not using plastics," but that was kind of the deal in aviation technology at the time. Aviation equipment is still pretty chunky today, because of the materials needed for low/no smoke evolution and vibration tolerance. Considering it probably also had to meet a MIL-STD environmental spec, stripping a commercial printer and putting it in some kind of aftermarket metal chassis seems like a much more expensive/higher risk route than using something that was already made to those standards. Environmental specs, in this context, usually mean min and max operating temperatures and acceptance of vibration and shock, within certain G-force and frequency measurements, with "without malfunction" and "without damage" thresholds. Aviation and military equipment have to go to environmental testing laboratories to be certified to these requirements, which can be a considerable expense on its own, and another reason it's smart to use an existing design. Besides, the military already made use of teleprinters in aircraft and so there was operating experience to build confidence. The space shuttle model is based on the family made by MITE, which included airborne variants used on bombers for example.
- throw0101c 2y ago
  > […] and vibration tolerance. Never thought of this before, but rocket launches are quite the event. Doing a quick search, see perhaps ISO 10816: * https://acoem.us/blog/other-topics/understanding-the-iso-10816-3-vibration-severity-chart/ https://acoem.us/blog/other-topics/understanding-the-iso-108... Amongst others: * https://vibrationresearch.com/blog/understanding-nasa-std-7001-test-parameters/ https://vibrationresearch.com/blog/understanding-nasa-std-70... * https://vibrationresearch.com/testing-standards/ https://vibrationresearch.com/testing-standards/ * https://www.avmc.army.mil/Portals/51/Documents/TechData%20PDF/ADS27ASP.pdf https://www.avmc.army.mil/Portals/51/Documents/TechData%20PD...
shadowpho 2y ago
>Were commercially available dot-matrix or daisy-wheel printers toxic or flammable? It’s not a binary but spectrum. For example military has a long list of standards for wires. The ships/tanks/planes use different wiring than your house does. That doesn’t mean our wires are toxic and flammable but they are probably more toxic/flammable than the application calls for. And here is the problem: there was no off the shelf printer that met their exact requirements on paper. It’s possible some of the printers were similar quality but they were not certified to same standard. So NASA would call a printer company and ask “does your printer self extinguish? What about in 100% oxygen? What about inrush current? Does the motor stall and what are the protections?”. The printer company would not want to spend the time/energy on that vs what nasa would be willing to pay for 5-10 printers.
- ahoka 2y ago
  “The printer company would not want to spend the time/energy on that vs what nasa would be willing to pay for 5-10 printers.” Epson did a bit more than a decade later.
akira2501 2y ago
There were several classified shuttle missions. In those missions their link capacity was severely degraded and had to run through encrypted military rather than open NASA civilian channels. This became an issue on STS-27 where they were unable to inspect tile damage with high resolution imaging because of these limitations. The astronauts on this mission were not at all pleased with the situation, and they had good reason not to be, as an entire tile had become dislodged by foam during the ascent.