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Reverse-engineering the Apollo spacecraft's FM radio
- bouvin 4y agoIf you ever wanted to use the sound of the Apollo transmissions creatively, the Lunar Module [1] is possibly the most niche of Eurorack modules. [1] https://ajhsynth.com/Lunar.html https://ajhsynth.com/Lunar.html
- drunkonvinyl 4y agoThat is the coolest niche module I’ve ever seen. Looking for used ones on reverb now.
- rwmj 4y agoIs it a surprise they didn't use PCBs? I thought by the 50s and 60s PCBs were an established technology.
- davidwritesbugs 4y agoI was also very puzzled by this, I've seen pin mounting before in very old equipment but as you say PCBs were in widespread use by the Apollo mission. Perhaps a conservative approach to technology, or did it have a cost/reliability implication?
- varjag 4y agoNo, they weren't quite an established technology by 1960. Also multi-layer PCBs weren't a thing, and two layers do not allow routing for the component density.
- kens 4y agoThe Apollo Guidance Computer and the LVDC used multi-layer printed circuit boards for the Apollo missions. I think the AGC was 7 layers and the LVDC 12.
- varjag 4y agoI stand corrected. Was it one of the project innovations though? Can't seem to recall ever seeing that myself on commercial period hardware.
- kens 4y agoIBM used multi-layer PCBs for the IBM System/360 (1964) so they were in use for some applications. But most electronics seemed to stick with two layers at most for a long time.
- asmithmd1 4y agoUltra premium guitar amps use point-to-point wiring: https://secureservercdn.net/50.62.89.49/34e.08c.myftpupload.com/wp-content/uploads/2017/12/IMG_5727_crop_800x800.jpg https://secureservercdn.net/50.62.89.49/34e.08c.myftpupload.... This guitar amp wiring looks much better than the Apollo radio
- klondike_ 4y agoPCBs during this time period were very brittle and fragile. The board itself was prone to cracking under high heat and the traces could easily lift off the board. Not a good fit for the hot vacuum tube circuits of the era. Zenith and other manufacturers often advertised point-to-point wiring as a feature for reliability
- ninefathom 4y agoSeconded. I've worked with PCBs of that vintage quite a bit- both recently and closer to their era. They are absurdly heavy and fragile by modern standards, and were very prone to having the traces lift off the boards, to the point of being notorious for sudden electrical shorts. If memory serves, that problem persisted at least through the 1980s. I'm sure there was a technological development of PCBs that eased the issue; somebody who knows more on that subject may be able to clarify.
- iasay 4y agoThey did. Just not in aerospace until the mid 1960s when decent quality fibreglass (FR4) boards were available. The previous SRBP and Bakelite boards were fragile and/or hygroscopic.
- kens 4y agoThe Apollo hardware is a mixture of various technologies. Some pieces (like the Apollo Guidance Computer and the LVDC) used printed circuit boards. But point-to-point wiring was also very common. So PCBs existed but weren't dominant.
- bilsbie 4y agoIs this also the technology that allowed the president to have a real time phone call with astronauts on the moon?
- kens 4y agoThe module I looked at was in the Command Module, so Nixon's telephone call would have gone through slightly different hardware on the Lunar Module.
- zoomablemind 4y agoVery methodical narration - pleasure to follow! I wonder if the reverse-engineered modules ended up functional, or the objective was only to determine the missing pin part. Was the silicone used to simply immobilize the mounted components or for other purposes like cooling, fire retardation?
- kens 4y agoThe objectives were curiosity (understanding how it works) and finding the missing pin so we can power up the module. The reverse-engineering isn't good enough to build a new one, e.g. I didn't figure out the capacitor values. I don't think the silicone had any other purpose than keeping the components in place.
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