[HN Gopher] Inside the digital clock from a Soyuz spacecraft
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Inside the digital clock from a Soyuz spacecraft
Author : eaguyhn
Score : 101 points
Date : 2020-01-17 17:41 UTC (5 hours ago)
(HTM) web link (www.righto.com)
(TXT) w3m dump (www.righto.com)
| m0zg wrote:
| 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.
|
| 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.
| gautamcgoel wrote:
| Great piece of history. Can someone explain the difference
| between TTL and CMOS chips?
| kens wrote:
| I'm not sure how much explanation you want. The short answer is
| that TTL (transistor-transistor logic) is an older logic
| family, while CMOS (complementary metal oxide semiconductor) is
| what's used nowadays, such as in microprocessors.
|
| In more detail, first there were bipolar transistors (NPN and
| PNP) and later MOS transistor (NMOS and PMOS). Bipolar
| transistors are your basic semiconductor transistors with three
| layers of semiconductor. MOS (metal oxide semiconductor)
| transistors have an insulating oxide layer between the silicon
| and the metal (or polysilicon) on top. MOS transistors were
| developed later than bipolar, and started to become popular in
| the 1970s.
|
| One type of logic that you can make from bipolar transistors is
| TTL (transistor-transistor logic). TTL is better than earlier
| logic families such as resistor-transistor logic (RTL) or
| diode-transistor logic (DTL). TTL was cheap, reliable, fast,
| easy to use, and popular with minicomputer manufacturers. TTL
| has two main problems, though. It uses a fair bit of power, and
| you can't make it very dense. I.e. you can't put a lot on a
| chip.
|
| MOS, on the other hand, has the advantage that you can make
| very dense circuits from it. (I.e. Moore's law applies.) NMOS
| was used for early microprocessors such as the Z-80 and 6502.
| The problem with NMOS is that it uses resistors (sort of) in
| the logic gates, and these waste power.
|
| The solution was CMOS, complementary MOS. You use both NMOS and
| PMOS transistors (the complementary part), and you can get rid
| of the resistors, and your chip uses very low power. The
| problem with CMOS is it's more complicated because you need two
| types of transistors, and twice as many (sort of). However, the
| need for low power won out in the mid-1980s and microprocessors
| such as the 80386 started using CMOS. Use of CMOS has continued
| to the present.
|
| I'm oversimplifying the history somewhat. The books "To the
| digital age" and "History of semiconductor engineering" go into
| much more detail.
| rdtsc wrote:
| > 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
|
| 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?
|
| > The logos on the integrated circuits reveal that they were
| manufactured by a variety of companies.
|
| 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
| http://madelectronics.ru/book/prominfo/2009-04-16-08-29-39-3....
| ben7799 wrote:
| This article is great... much thanks to the author.
|
| This kind of stuff is fascinating.
| flipflipper wrote:
| >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.
|
| 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.
|
| More detail on grounding and isolation in S/C is covered here:
| https://standards.nasa.gov/standard/nasa/nasa-hdbk-4001
| blakes wrote:
| Here is the video where they open up this very clock for the
| first time: https://www.youtube.com/watch?v=JBIhzEZkWEA
| blattimwind wrote:
| > 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.
|
| 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.
|
| > 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.
|
| 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).
|
| > The Russian diodes have orange rectangular packages (below),
| unlike the usual cylindrical American diodes.
|
| Semiconductor packages were all over the place in the past; I've
| seen cube-ish moulded diodes, resistors and capacitors in
| European stuff.
|
| 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.
|
| > 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.
|
| 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.
| rzzzt wrote:
| Ceramic side-brazed DIPs look very futuristic to me for some
| reason, especially when the carrying substrate is light
| colored. Plastic packaging is pretty dull in comparison.
| dfox wrote:
| Wrt. to flatpaks it is somewhat interesting to note, that very
| often when there is some kind of ASIC (think alarm clock or
| calculator or even "PDP-11 on a chip") in 80's soviet consumer
| electronics it is packaged in metal/ceramic hermetic flatpack
| with legs bent and THT soldered.
| cstross wrote:
| > Due to the end of the Space Shuttle program, Soyuz is now the
| only spacecraft capable of carrying a crew into orbit
|
| So I'm guessing the Shenzhou program doesn't count?
|
| https://en.wikipedia.org/wiki/Shenzhou_(spacecraft)
|
| (Yes, I know the OP goes on to say "and used for flights to the
| ISS". Still irritatingly inaccurate.)
| kens wrote:
| Thanks for the comment; I've removed the offending sentence.
| (edit: cstross is right and doesn't deserve downvotes.)
|
| Wikipedia says "Soyuz has served as the only means for crewed
| space flights in the world since the retirement of the US Space
| Shuttle in 2011", so I guess that's wrong?
|
| https://en.wikipedia.org/wiki/Soyuz_(spacecraft)
| mschuster91 wrote:
| The Chinese program is China only, unavailable to the rest of
| the world - Russia in contrast sells to everyone, meaning
| that "the world" only has Russia as provider.
| daveslash wrote:
| Thanks Op. How did you come into possession of this clock?
|
| Edit: And does it still work?
| kens wrote:
| CuriousMarc [1] bought the clock at a space auction. We
| hope the clock still works. We plan to power it up and get
| it working, but first I needed to reverse-engineer the
| circuitry to figure out how to power it.
|
| [1] https://youtube.com/curiousmarc
| oldgradstudent wrote:
| Isn't Shenzhou a Soyuz derivative?
|
| You could say it makes the original statement unintentionally
| true.
| ericwood wrote:
| _While American resistors are usually labeled with colored bands,
| the Russian resistors are green cylinders with their values
| printed on them_
|
| _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._
|
| 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.
| jgrahamc wrote:
| I agree on the resistors. The resistor colour code coupled with
| poor quality of colours on the actual resistors has me
| frequently reaching for a multimeter to just measure the
| resistance.
| daveslash wrote:
| The descriptions of the American components (resistors, diodes,
| etc...) reflect what I've seen in all of the consumer
| electronic components that I've busted-open here in the U.S. --
| ones which are often made outside of the U.S.
|
| The fact that these consumer electronics are built according to
| the American way as opposed to the Russian way - is that a
| reflection of selling to a U.S. market, U.S. companies
| selectively working with manufacturers that do things in a
| familiar way, general wide-adoption of the U.S. ways, or
| something else?
|
| If I were to be in Russia or a former Soviet state, would I see
| consumer electronics looking more like this Soyuz clock?
| dfox wrote:
| Surprisingly large amount of soviet era consumer electronics
| are built quite similarly and use what in essence are
| military/space grade parts (and meticulously made cable
| looms). I assume that this is simply caused by using whatever
| was available in large enough quantity in combination with
| slightly different engineering culture (cable looms!).
| dfox wrote:
| If I think about it I probably can pinpoint the reason for
| the soldered cable looms: not only in SSSR but across the
| whole eastern block in general there simply weren't any
| reasonably cheap and reliable board to board or board to
| cable connectors for general use with reasonable density.
|
| Edit to add: there were various ribbon cables used in
| eastern block electronics, but mostly with hand soldered
| connectors, not IDC. Two exceptions I can think of are
| Shugart-compatible floppy drives (although some Czech
| computers actually use ribbon cables with hand soldered
| board-to-card connectors) and some Metra-branded
| measurement equipment which uses MicroD-like IDCs
| internally.
| blattimwind wrote:
| It's a reflection of color coding (with painted rings or
| dots) being vastly cheaper than printing text proper. Many
| lower cost European transistors (almost exclusively the TO-92
| variety) were marked with colored dots or half-rings.
| Similarly some film and tantalum capacitors were marked with
| colored dots as well.
|
| Precision or otherwise higher grade (e.g. ceramic wirewounds)
| components were always usually marked with text.
| ani-ani wrote:
| This led me to this declassified document according to which
| Soviets used a mix of color codes and directly stamping values
| on resistor housings:
|
| https://www.cia.gov/library/readingroom/docs/CIA-RDP80-00809...
|
| The document is from 1950 though, so it greatly predates the
| standards used the 1983 Soyuz here.
| gen3 wrote:
| I'm color blind. The markings would make everything so much
| easier. Having to check with someone else to make sure I get my
| colors right is such a pain. I hope I can order some.
|
| Edit: If anyone can find labeled resistors for a reasonable
| price, I would be grateful.
| __jal wrote:
| Some time ago I saw an Iphone app that could "read" resistors
| by pointing your camera at them, but can't find it now.
|
| Googling, I see one for Android, which I don't use:
|
| https://play.google.com/store/apps/details?id=com.mhdev.resi.
| ..
| lb1lf wrote:
| This is why I loved it when introduced to SMT devices. Rather
| than those pesky colour bands, values were stamped on in a
| rational manner - two digits value, one digit power of ten.
| Say, 106 for a 1MOhm resistor, 102 for a 100Ohm one.
|
| My lab productivity soared.
| gen3 wrote:
| I found some of them. They look super helpful. How do you
| breadboard things with them?
| lb1lf wrote:
| You mostly don't - I had a decent setup for etching, so I
| just quick-and-dirtied a layout, put down a few extra
| pads where I suspected I might need some, processed a
| board and gave it a go.
|
| The one important thing is to not pinch on the pincers -
| buy a good pair... :)
| blattimwind wrote:
| You can easily use protoboard instead. 0805 goes between
| two pads no problem.
| blackrock wrote:
| What's an example of the Russian nomenclature vs. the American
| style?
| Luc wrote:
| The conclusion seems a bit strange.
|
| _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._
|
| Because in the paragraph above:
|
| _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._
| kens wrote:
| The point is that the Shuttle's TTL chips were more advanced as
| far as performance, using Fairchild's FAST line. The Shuttle
| also used many TTL chips that were more complex. This is
| consistent with the CIA's claim that American ICs were 8 to 9
| years ahead. But it's interesting that the Shuttle was still
| using TTL, and many of the chips were very basic, like the quad
| NAND gate chip. So the difference between the two boards was
| surprisingly incremental, rather than a jump to MOS chips or
| microprocessors.
| m0zg wrote:
| It was way behind yes (and much of it was ripped off, China-
| style, from Western designs), but I agree it's weird to compare
| a _computer_ with a _clock_.
| ohadron wrote:
| It's amazing to think that this device was produced several years
| after the class simple casio watch we all know.
|
| Same functionality more or less, probably a fraction of the
| weight and cost.
|
| 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.
| dfox wrote:
| Assuming this thing was designed in early 80's (which it
| probably was given the LQ470-like DIL 7segment LED displays)
| there certainly was soviet made NMOS ASIC that implemented most
| of the functionality in single package. But similarly to
| contemporary western counterparts it required bunch of funky
| supply voltages (albeit the supply rails used by soviet alarm
| clock ASICs are nowhere near the supply funkiness of Sanyo's
| essentially AC powered alarm clock ASICs) and were nowhere
| reliable enough to be used in space.
| Waterluvian wrote:
| 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.
|
| What a really cool output device.
| kens wrote:
| That's the Globus IMP and dates back to 1964. Wikipedia has
| details:
| https://en.wikipedia.org/wiki/Voskhod_Spacecraft_%22Globus%2...
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(page generated 2020-01-17 23:00 UTC)