The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay.
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The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay. Three French-made computers ran Spacelab. I opened up a Spacelab computer and found that instead of a microprocessor, it is built from a multitude of simple chips. Let's take a closer look at the computer...
@kenshirriff So cool! Thanks for sharing
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The boards need a lot of chips because a chip didn't do much back then. Even the ALU chips had just 170 transistors. Multiplexers (mux) select which inputs to add, registers hold temporary values, and logic gates (NAND, inverters) tie things together.
@kenshirriff I've been studying these old ALU chips, as a way to teach myself about computer hardware design. 170 transistors is an amazing feat of engineering.
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The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay. Three French-made computers ran Spacelab. I opened up a Spacelab computer and found that instead of a microprocessor, it is built from a multitude of simple chips. Let's take a closer look at the computer...
@kenshirriff Compagnie d'informatique militaire spatiale et aéronautique - didn't know about this one (whence it came, what it became)
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The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay. Three French-made computers ran Spacelab. I opened up a Spacelab computer and found that instead of a microprocessor, it is built from a multitude of simple chips. Let's take a closer look at the computer...
哇，能亲眼看到Spacelab计算机的内部结构真是难得。用那么多简单芯片而不是微处理器来构建整台电脑，那个时代的设计思路还挺特别的。
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@LukefromDC @sandorspruit @kenshirriff Wrong : you can do an Apollo13 fixup if you have the guts to do so
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@kenshirriff I recall an electrical engineering professor back in the late 1970s who said the way to invent the better mousetrap was to figure out how to put one megabit of memory on a single chip.
His version of the Holy Grail.@bouriquet @kenshirriff Im old enough to remember the days when memory may be carried by a delay line. More fun then to data process.
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For more on the Spacelab computer, see my latest article: https://www.righto.com/2026/05/reverse-engineering-spacelab-computer.html
@kenshirriff Finally got to the end of the footnotes. GE only acquired Alstom's energy business, not the rail infrastructure business the company is now best known for, and despite taking that enormous write-off in 2018, the power turbine business that GE acquired is now a big part of the reason GE Vernova, post-breakup, is trading for $1000 a share and nearly 90% of the market cap of GE Aerospace (the old GE) after being spun off on a 1-for-4 basis.
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This circuit board had a few bugs, which were fixed on the back with yellow "bodge" wires.
@kenshirriff Do you think it was originally yellow, or white that has aged? I've seen people take "white wire" much more literally than seems necessary.
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@kenshirriff I've been studying these old ALU chips, as a way to teach myself about computer hardware design. 170 transistors is an amazing feat of engineering.
@kenshirriff @agreeable_landfall Even more amazing is that the transistors are merely miniature switches. Tech Trivia: logic gates originated with banks of relay switches developed by the telephone company. -
The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay. Three French-made computers ran Spacelab. I opened up a Spacelab computer and found that instead of a microprocessor, it is built from a multitude of simple chips. Let's take a closer look at the computer...
@kenshirriff When I read this great thread earlier, something about the name 'Spacelab' began gnawing at my brain. I new there was an earlier orbiting lab when I was a kid, but couldn't for the life of me sort it out. After going about my day, hours later it hit me out of the blue--SKYLAB!!! I knew it sounded the exactly same, but different!
And for anyone not familiar, this is what I'm prattling on about-
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@kenshirriff Do you think it was originally yellow, or white that has aged? I've seen people take "white wire" much more literally than seems necessary.
@wikkit This wire looks like it has always been yellow.
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@kenshirriff TTL? Or...?
I tried blowing up and sharpening that image but I still can't make out the numbers on those chips, alas. I still suspect TTL.
Edited to add that I blew up a different set of your pics with better results, and what threw me is that these are 77 series chips rather than 74 series, but I'm guessing that's because it's special MILspec for those; the 7714 is clearly equivalent to 7414, and none of those are post-LS technology.
Yep--TTL.@claralistensprechen3rd Yes, the chips are TTL, specifically 5400-series. But that's hard to see because the part numbers are mostly JM38510 military numbers. And 7714 is a date code (1977 week 14), not a part number.
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@LukefromDC @kenshirriff SpaceLab started development in the mid 1970s; it was one of the original Shuttle payloads. Designs for spaceflight tend to get frozen early on, so they can be extensively tested before use.
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@LukefromDC @kenshirriff You’d expect space tech to be fancy, but I think it takes ages to certify tech for such applications, so it is actually quite old?
@sandorspruit
Yes, I remember reading that shuttle electronics were frozen 1975. with true and proven technology, at that time
@LukefromDC @kenshirriff -
The Space Shuttle could hold a flying laboratory called Spacelab in its cargo bay. Three French-made computers ran Spacelab. I opened up a Spacelab computer and found that instead of a microprocessor, it is built from a multitude of simple chips. Let's take a closer look at the computer...
I love #TTL graves 🥰
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@LukefromDC @VoquiLeibbrandt @sandorspruit @kenshirriff landing as a glider isn't a bad option on the amphibious models where you might stand a chance of taking back off again. I always quite liked that idea.
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