>> However, the power supply uses a more complicated design to provide electrical isolation between the spacecraft and the clock. I'm not sure, though, why isolation was necessary.<p>Because soviet spacecraft, as with all spacecraft at that time, were designed to survive all sorts of failures. The clock is an absolutely essential part of the spacecraft. It needs to keep running even when everything else is failing, especially when everything else is failing. A space clock needs to be both integrated into a dozen other systems, and able to cut itself from those systems when necessary. Cosmonauts in a failing capsule, waiting to fire the return burn necessary to get home, won't be looking out the window. They will be looking at that clock.
> These are mostly 14-pin "flat pack" integrated circuits in metal packages, unlike contemporary American integrated circuits which were usually packaged in black epoxy. There are also some 16-pin integrated circuits, encased in pink plastic.<p>It's worth pointing out that flatpacks (both ceramic and EP) were and probably still are a mainstay of military and aero electronics. These were never used in consumer electronics. Apart from microprocessors and EEPROMs, consumer electronics never really used ceramic or hermetic metal packages for cost reasons. Perhaps the most common components would be TO-3 power transistors and small metal can transistors before TO-92 and similar packages obsoleted all of those.<p>> Many of the components in the power supply look different from American components. While American resistors are usually labeled with colored bands, the Russian resistors are green cylinders with their values printed on them.<p>High grade or high precision resistors usually had their value printed on them, though. Meanwhile, only larger SMD resistors have markings today (I think they stop applying them below 0604 imperial).<p>> The Russian diodes have orange rectangular packages (below), unlike the usual cylindrical American diodes.<p>Semiconductor packages were all over the place in the past; I've seen cube-ish moulded diodes, resistors and capacitors in European stuff.<p>Overall this thing looks a lot like something from the mid 60s, not so much mid 80s. In that case, American stuff from the same period looks pretty similar, quite possibly due to copious copying by the Russians.<p>> One nice thing about Russian ICs is that the part numbers are assigned according to a rational system, unlike the essentially random numbering of American integrated circuits.<p>On a related note, I really like IEC/ISO schematics for this reason, because we have a graphical language to describe logic and this means logic devices appear as a composition of symbols which explain the function of the gate to anyone who knows this language. On American schematics only the most basic gates (AND, OR, NOT, ...) have symbols, everything more complicated than that is generally drawn as a box with the part number ('193) in it and the pins just labelled with their abbreviations.
<i>While American resistors are usually labeled with colored bands, the Russian resistors are green cylinders with their values printed on them</i><p><i>One nice thing about Russian ICs is that the part numbers are assigned according to a rational system, unlike the essentially random numbering of American integrated circuits.</i><p>This makes so much sense, it's a shame this style of labeling didn't catch on. It would have made my EE labs in college so much easier.
>However, the power supply uses a more complicated design to provide electrical isolation between the spacecraft and the clock. I'm not sure, though, why isolation was necessary.<p>I believe this is to maintain a single point ground, usually the chassis on a spacecraft. The chassis of the clock is probably connected to the isolated side's ground, which avoids ground loops when the clock is integrated into the S/C.<p>More detail on grounding and isolation in S/C is covered here: <a href="https://standards.nasa.gov/standard/nasa/nasa-hdbk-4001" rel="nofollow">https://standards.nasa.gov/standard/nasa/nasa-hdbk-4001</a>
Okay that physical globe as an item on the Soyuz dashboard is amazing. I need to know more about that. I imagine it's gimballed and a computer moves it to the GPS or dead reckoned position as the Soyuz orbits over the Earth.<p>What a really cool output device.
> Russian resistors are green cylinders with their values printed on them. The Russian diodes have orange rectangular packages (below), unlike the usual cylindrical American diodes<p>They have color coded Russian resistors, probably just for smaller sizes. Diodes have a variety of shapes, but I don't remember seeing rectangular packages like that one either. Some of those component might have also been specially sourced high tolerance components that might be different than what you'd find in consumer electronics?<p>> The logos on the integrated circuits reveal that they were manufactured by a variety of companies.<p>Oh very interesting. I have been wondering about what those logos meant when I used to play with electronics back in the day. They even have a link to the full list <a href="http://madelectronics.ru/book/prominfo/2009-04-16-08-29-39-318.htm" rel="nofollow">http://madelectronics.ru/book/prominfo/2009-04-16-08-29-39-3...</a>.
The conclusion seems a bit strange.<p><i>Why does the Soyuz clock contain over 100 chips instead of being implemented with a single clock chip? Soviet integrated circuit technology was about 8 years behind American technology, so TTL chips were a reasonable choice at the time.</i><p>Because in the paragraph above:<p><i>I expected the Shuttle computer to use 1980s microprocessors and be a generation ahead of the Soyuz clock, but instead the two systems both use TTL technology, and in many cases almost identical chips.</i>
> Due to the end of the Space Shuttle program, Soyuz is now the only spacecraft capable of carrying a crew into orbit<p>So I'm guessing the Shenzhou program doesn't count?<p><a href="https://en.wikipedia.org/wiki/Shenzhou_(spacecraft)" rel="nofollow">https://en.wikipedia.org/wiki/Shenzhou_(spacecraft)</a><p>(Yes, I know the OP goes on to say "and used for flights to the ISS". Still irritatingly inaccurate.)
Even back then, the Soviet space program had the electronics to make this much less complicated. Remember, in 1986 they had the Buran shuttle which flew to the orbit and landed fully autonomously, under computer control.<p>The clock was probably developed much earlier, and then perhaps slightly modernized with LEDs and such. Developing a new clock for spacecraft would probably take a year or two, for all the testing and certifications, so nobody bothered.
It's amazing to think that this device was produced several years after the class simple casio watch we all know.<p>Same functionality more or less, probably a fraction of the weight and cost.<p>I'd attribute the difference to how military/government projects pan out and not necessarily to the less advanced soviet IC abilities. There are many similar examples in western military equipment.
I just noticed that HN has the mobile link to my article, so the images are fairly small. You can click on an image to see a larger version, or go to the regular site: <a href="http://www.righto.com/2020/01/inside-digital-clock-from-soyuz.html" rel="nofollow">http://www.righto.com/2020/01/inside-digital-clock-from-soyu...</a>
Here is the video where they open up this very clock for the first time: <a href="https://www.youtube.com/watch?v=JBIhzEZkWEA" rel="nofollow">https://www.youtube.com/watch?v=JBIhzEZkWEA</a>
> While American resistors are usually labeled with colored bands, the Soviet resistors are green cylinders with their values printed on them.<p>Smart! The color band system has +ve and -ve, but overall I hate it. But better than caps with their 104 = 100,000 pf/nF?<p>I've known the US color band system since I was a kid, but damn the base color of the resistor epoxy has a huge impact, as does the low wattage high precision: you need a magnifier to read all 5 bands on a 4mm resistor.