Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Space Hardware

Build Your Own Apollo Guidance Computer 218

Posted by michael from the some-assembly-required dept.
PingXao writes "Well, if you can't exactly give the Moon you can give the gift of a computer to get you there. Almost a year ago this Slashdot story about the Apollo 11 Guidance Computer referenced a pretty cool Dr. Dobbs Journal article from their History of Computing series. Now there's this guy who built one in his basement! It took him 4 years, $2,980 in cash, 2,500 hours of labor and 15,000 hand-wrapped wire connections with 3,500 feet of wire to build. It might be next Christmas before you could build one of your own to give as a gift, but he promises you can build your own for less and it will be better than his. The perfect gift for the space geek who has everything. This guy is my hero."
This discussion has been archived. No new comments can be posted.

Build Your Own Apollo Guidance Computer More

Build Your Own Apollo Guidance Computer

Comments Filter:

  • Kinda makes you wonder, (Score:4, Insightful)

    by DoraLives ( 622001 ) on Friday December 24, 2004 @09:07PM (#11179298)
    with those old boxes, how in hell did they ever make it to the moon and back alive.

    • Re:Kinda makes you wonder, (Score:5, Insightful)

      by Detritus ( 11846 ) on Friday December 24, 2004 @09:12PM (#11179314) Homepage
      They had IBM 360s and other big iron on the ground to do the heavy-duty calculations. If you have a choice between doing something on the ground and doing it on board the spacecraft, it's almost always better to do it on the ground.

      • Re:Kinda makes you wonder, (Score:5, Insightful)

        by Glonoinha ( 587375 ) on Friday December 24, 2004 @10:41PM (#11179544) Journal
        Heh.
        Most of us wear watches with more horsepower than a single System 360 of the time.
        I would imagine that every computation performed at all of NASA from T minus 10 until splashdown could grind through my desktop in less time than it took me to reply to this message.

        The difference wasn't in the hardware.
        It was in the people, their abilities, and in the working relationship those people had with each other.
        It was in the management of those people, putting success and excellence above all else.
        It was in the work - putting men on the moon wasn't just a job, it was an adventure and it was a dream.
        • Even so, they could use a hell of a lot of ground-based computing power that they simple couldn't afford to boost to orbit, let alone loop around the moon... It might not be fast by today's standards, but I'll bet they had more tonnage of computers available than the whole weight of the Apollo Lunar orbiter & lander

        • Re:Kinda makes you wonder, (Score:4, Insightful)

          by bigberk ( 547360 ) <bigberk@users.pc9.org> on Friday December 24, 2004 @11:26PM (#11179654)
          The difference wasn't in the hardware. It was in the people... it was an adventure and it was a dream.
          I agree with you. Look at the incredible computation abilities we now have, it really boggles the mind. We have made leaps forward in speed, miniaturization, and power usage. Materials science has also brought us an entirely new set of possibilities since then. Now, if we had a real goal -- like to start human exploration of space in earnest (longer missions, more frequent), I think we could really do some amazing things.

          Personally I think we're being really stupid by not funding more space exploration. Yes, I know people on earth are starving. But both you and I know that it's not the starving Ethiopians competing with NASA or ESA for funding...

          • Re: (Score:2, Insightful)

            by account_deleted ( 4530225 )
            Comment removed based on user account deletion
            • "There is really precious little to be learned from travel outside our own atmosphere with the technology currently available that cannot be learned more conclusively and safely here on Earth. When one combines this fact with the enormous cost of getting all but the most insignificant payloads into orbit, there is a very persuasive argument for forgetting about our space travel dreams, at least for the present."

              Which completely misses the point - it's not the learning, it's the doing that matters.
            • Ummm yea you are going to make warp drive for us next week right after cold fusion.
              Sorry but it burns me when I hear science blindness. Yea theoretical physics is important and yes the average person has no clue what is is. But I really doubt that if you got the funding of a Live Aid you would get us beyond the solar system in "No Time"
              All science is important and all of it needs funding but your statement is just wrong. Do you have any idea how important it would be if we found life on Mars or Europa?
              How i
            • Quite right. The payloads we are currently capable of boosting are useless for any real development of space. If we are to have the future we dream of, we're going to have to find (and fund) another way to do it.

              Yes, we are certainly capable of sending small probes out to discover facts about the solar system, but those facts will remain useless until we can get there in person.

              I remember reading a statement somewhere regarding rocket tech, along the lines of 'a 5% increase in current booster efficiency

          • Your post made me think of this:

            I'm gonna share with you a vision that I had, cause I love you. And you feel it. You know all that money we spend on nuclear weapons and defense each year, trillions of dollars, correct? Instead -- just play with this -- if we spent that money feeding and clothing the poor of the world -- and it would pay for it many times over, not one human being excluded -- we can explore space together, both inner and outer, forever in peace. --Bill Hicks
        • Don't underestimate the IBM 360 series of computers. They had I/O capabilities that surpass many modern computers. The Space Shuttle's on-board computers were based on a mutated version of the 360 architecture. Many of the architectural advancements in microprocessors were just recycled ideas from the IBM 360 series and other large computers from the 1960s.
          • This piqued my interest. Do you have any source info about that?

            • Re:Oh? (Score:3, Insightful)

              by Detritus ( 11846 )
              Your best bet is to take a course in computer architecture or pick up a textbook on the subject, esp. one that has a good survey of older computers that introduced significant architectural advances.

              The IBM 360/91 was an important high-performance member of the IBM 360 family. The CDC 6600 was also an innovative system from the same era.

              The Space Shuttle uses the IBM AP-101. See Computers in Spaceflight: The NASA Experience [nasa.gov].



        • I bet there wasnt a single engineer during the entire flight that didn't know where their sliderule was at any point in time.
        • putting men on the moon wasn't just a job, it was an adventure and it was a dream.


          But they did get paid. And they didn't get paid a below-average salary plus stock options that may or may not be worth something someday. And they were doing a great duty to their country by fighting the communists in the space race. Where is that spirit today? Maybe in companies building anti-terrorist weapons or something?

    • Re:Kinda makes you wonder, (Score:5, Funny)

      by Average_Joe_Sixpack ( 534373 ) on Friday December 24, 2004 @09:15PM (#11179326)
      Easy, they weren't bogged down with a GUI.

    • Re:Kinda makes you wonder, (Score:5, Insightful)

      by UniverseIsADoughnut ( 170909 ) on Friday December 24, 2004 @09:50PM (#11179425)
      well, you could do it without computers, would just be even harder, plus astronauts would have one sucky time flying the craft by hand to the moon. But it could be done, there is always a way without a computer.

      The other thing is they took a very simple approach to thing, to do it today would be even harder because we would over complex thing thing with uber redundancy and sensors for everything and so forth. Thus why we could get to the moon, or russians get space stations, but the space shuttle and space station suck.

      Not that getting more computers involved is bad, it just makes it easier for things to crap out and not know why. Mechanical stuff is easy to figure out why it's not working, electrical not so much, and code and semiconductors very hard.

      I too look at how we did it, am are amazed it all worked. But then, look at a Model T or a Steam Locomotive, today it seams amazing people would trust those thing cross country or that they would be very durable, but they did it just fine.

      I'm pretty sure my powermac has failed on my more then my atari 800 ever did.

      • Comment removed (Score:4, Interesting)

        by account_deleted ( 4530225 ) * on Friday December 24, 2004 @11:38PM (#11179682)
        Comment removed based on user account deletion

        • Re:Kinda makes you wonder, (Score:5, Insightful)

          by UniverseIsADoughnut ( 170909 ) on Friday December 24, 2004 @11:53PM (#11179726)
          well, they are unstable for the purpose of getting better performance, not to make the concept of planes to fly work. You can build a plane without a computer, and could achieve the same basic concepts, but it wouldn't do it as well.

          Also, planes like the Stealth Bomber are said to not be able to fly without a computer for reasons like you mentioned, especially landing it. But really it's a issue of it makes it practical, not needed. The Northrop flying wing worked in the late 40s and it obviously had no computers. The B2 is based off that planes design (actually has the exact same wing span), the computers just made it more feasible and overall better.

          In the case of going to the moon, it could be done without a computer, rockets went up without computers, plus people make a great computer. The computers for apollo did pretty straightforward stuff, and were mainly there so the astronauts didn't have to keep doing stuff non-stop. They could still sight stars and calculate there path and manual fire rockets to adjust (like they did in Apollo 13),

          The thing is we have all gotten so used to doing stuff with a calculator that we forget you can do it without. When was the last time you did a square root by hand (or even remember how). I think this is the kind of thing that causes people to wonder how things like the pyramids were made, people just can't think of how to do things without modern tools, cause thats all they know. To the Egyptians building them probably wasn't that hard to figure out.
          • Not quite, the Soviet space program was big into sequencers. That is glorified timers that controlled the mission. Pretty easy and reliable tech and well known from missilies. However, they are pretty hopeless if you wanted to change a sequence mid flight. Otherwise they used dedicated guidance systems (coupled gyros), which again was old tech.

            The Saturn V itself had quite a lot of processing power for the day. The LEM and CM/SM were fully controllable. The basic programs were in ROM but they could be use

      • There's a Heinlein quote that I'm trying to think of, that goes something along these lines:

        There are three stages to the development of any technical project. In stage one, the device is simple, does only what it needs to, and works most of the time. In stage two, the device is vastly overcomplicated, overpowered, does far more than it needs, and works occasionally. In stage three, the "improvements" are thrown out, the device is again simple, does only what it needs to, and works all the time.

        I've bee

      • Actually you are completely wrong. Computers for the most part make things simpler and more reliable. Ever take a look at a mechanical fuel injection system? It is a nightmare.
        The shuttle does not suck because of the computers used. It has issues because it is and should have always been thought of as an experiment. It was talked up as space DC-3 when in truth it was more of a Vicker Vimy. Not to mention it was an underfunded experiment.
        The Model T compared to a modern car SUCKS.
        A modern car will go 100,000
        • The Model T compared to a modern car SUCKS

          The Model T entered the market when there were no hard surfaced roads or trained auto mechanics outside the cities, no high octane gasolines, no gas stations, no certainty that fuel or lubricants would be as advertised.
          Under those conditions, a simple, tough, forgiving, automobile with a 20hp engine that can cruise comfortably at 35-40, and gets 20-30 mpg doesn't look half-bad.

        • Mechanical fuel injection IS a nightmare. it's also not a good idea. Normal aspiration systems for cars works better, and can be tuned by anyone with a half a brain to work better than fuel injection.
      • But it could be done, there is always a way without a computer.

        We didn't really discover fractals until we had computers. To solve a 100x50 grid of complex numbers, squaring them for a two hundred iterations each is a million multiplications. And that would get you the outer impression of the Mandelbrot, but if one didn't know of fractals, one might even miss that it was self-affine at that level. To get that point would be superhuman; to investigate further would defintely need a computer.
        • We didn't really discover fractals until we had computers.

          Tell that to Julia - he seemed to manage okay without electronic computational power. Mandelbrot used computers to refine his work and do ever more complex sets.
    • with those old boxes, how in hell did they ever make it to the moon and back alive.

      It takes more computational power to provide a retarded paperclip assistant than it does to go to the Moon.

  • Fantastic (Score:5, Funny)

    by Icarus1919 ( 802533 ) on Friday December 24, 2004 @09:08PM (#11179302)
    Now all he has to do is build his own apollo 11, and he's all set to go to the moon! He just has to pay a few hundred million to get the rockets to take it up.

    • He just has to pay a few hundred million to get the rockets to take it up.

      Unless he outsources the propulsion systems to India, of course.

    • He just has to pay a few hundred million to get the rockets to take it up.

      <conspiracy>Awww c'mon, with todays high tech video software at everyone's finger tips, you could fake a better moon landing for way less than that!</conspiracy>

  • Give it as a gift? (Score:5, Funny)

    by Prophetic_Truth ( 822032 ) on Friday December 24, 2004 @09:11PM (#11179313)
    [me] HI AUNT EDNA! Look what I built for you! Its an exact replica of the Apollo guidance computer!
    [Aunt Edna] uh, thanks?
    • [me] HI AUNT EDNA! Look what I built for you! Its an exact replica of the Apollo guidance computer!
      [Aunt Edna] uh, thanks?

      Or:

      [Aunt Edna] I'm not *that* old, you little shit.
    • For ME.
      Or perhaps some other geek on your Christmas list.

      Even better yet would be a kit, so the recipient would get the fun of assembling the project him<M-Del>themself.

      It's too bad all kids nowdays have the attention span of an albino ferret, this'd be a GREAT educational project....
      • Very, very few kids have a grasp of the math necessary to understand microprocessor design. The ones who do probably have no need to be inspired to learn, they probably enjoy it enough as it is. I don't know how complex this CPU is, but somehow I doubt it would be a whole lot more instructional than learning assembly on an LC2. Which would also take significantly less time and be more practical. I associate this with something along the lines of say, the CPU geek version of civil war re-enactments.

  • I don't understand.. (Score:2, Interesting)

    by IGTeRR0r ( 805236 )
    I understand that it took him a long time and it's quite an incredible feat, but how is it usable/testable? Apollogize for my stupidity.
    --
    http://www.gamercentric.com/ [gamercentric.com] - Now with a clan and tournament system!

  • Or... (Score:3, Funny)

    by binderhead126 ( 809883 ) on Friday December 24, 2004 @09:14PM (#11179320)
    You could just hack a Gameboy Advance, and have even more horsepower! To the MOOOOOOOOOOOOON!!!!!!!!

  • yea but... (Score:5, Funny)

    by mindwar ( 708277 ) on Friday December 24, 2004 @09:14PM (#11179321) Homepage
    will it run Linux? ... or at least NetBSD?

    • Re:yea but... (Score:3, Interesting)

      by jd ( 1658 )
      NetBSD will just about run on those CPUs they use in washing machines. As for Linux, well, if the ELKS project is still alive, then you can just about run Linux on anything 8 bits or larger.

      People can (and have) ported just about anything to anything. There's a version of X11 that runs entirely under Java. There are patches to make Linux run on a VAX. Hell, ply Linus, Alan Cox and Richard Stallman with enough beers, I'd be willing to bet you could talk them into developing the necessary hooks in Linux, GC

      • "The Intel 80286, a 16-bit processor with a segment-based memory management and protection system. The 80386 added a 32-bit architecture and a paging translation unit, which made it much easier to implement operating systems which used virtual memory." which the linux kernel needs. A few years ago I spent time picking through trash trying to find a 386 so I could try linux. There's some un*x variants that will poke about on Z80 and 6502- but not linux. M$ used to put out Xenix, a un*x that ran on 286s, th

    • Re:yea but... (Score:3, Funny)

      by new500 ( 128819 )
      will it run Linux? ... or at least NetBSD?

      Yeah, but based on what i read about the original, i bet BillG wishes he could port NT to it :

      "Shortly after liftoff of Apollo 12, two lightening bolts struck the aircraft. The current passed through the command module and induced temporary power failure in the fuel cells supplying power to the AGC. During the incident the voltage fail circuits in the computer detected a series of power trenches and triggere several restarts. The computer withstood these without

  • I bet someone could write an emulator that runs on a Palm or something similar.

  • Every operating system sucks... (Score:5, Funny)

    by powerlinekid ( 442532 ) * on Friday December 24, 2004 @09:18PM (#11179333)
    you see, I come from a time in the nineteen hundred and seventies
    when computers where used for two things
    too either go to the moon or play pong
    and nothing inbetween, you see
    and You didn't need a fancy operating system to play pong
    and the men who went to the moon, god bless them
    did it with no mouse
    and a plain text only black and white screen
    and thiry-two kilobytes of ram

    Beyond that, this guy is lucky its christmas because with multiple 4-9 meg pdf files it would be a silent night for his server.

  • And now it's been linked to by Slashdot. (Score:5, Funny)

    by Nanoda ( 591299 ) on Friday December 24, 2004 @09:21PM (#11179340)
    10$ says it's flashing "1202" right about now...

  • FPGA (Score:4, Insightful)

    by saned ( 736423 ) on Friday December 24, 2004 @09:37PM (#11179398) Homepage
    Not to undermine his job, which I think is a major accomplishment, not only by building it but by reimplementing the whole logic from diagrams. But looking at the logic, it seems it could fit easily in a Spartan 3 FPGA. So yes, it could be done cheaper and faster, but not with the degree of detail this guy put on.

    Kudos to him

    • Re:FPGA (Score:2, Insightful)

      by murderlegendre ( 776042 )

      But looking at the logic, it seems it could fit easily in a Spartan 3 FPGA.

      Pretty amazing, isn't it; how far we have come in so little time.. And the fact that this guy took the time to properly execute the project, and document it as he went along, really allows one to gain a sense of scale when it comes to computing devices. This thing has about as much computing power as an Atari-2600 and it takes a truck to move it. And just about ten years later, we were playing pong in the living room.

      And it too

    • Yea I was thinking the same thing. An FPGA could make a single chip AGC.
      I almost want to download the emulator and see what I can write for it.
  • $3k + 1.25 man-YEARS of labor... wow.

    Even at chinese outsourcing prices, that's one VERY expensive project that doesnt do anything useful.

    Go get an Apple ][, you can learn just as much for $50 ;)
    • Time is far, far more precious than money. We only trade *some* of our time for money so we can use that money during the remaining time.
    • >>Go get an Apple ][, you can learn just as much for $50 ;)

      I disagree. This project completely rules. It's way more than just tinkering around with an Apple ][ -- it's the equivilent of building an Apple ][ from scratch, reverse engineering Applesoft, the monitor, the Sweet 16 emulator, the LISA assembler, building a floppy drive, etc. etc. etc.

      Go read the articles and you'll appreciate what a tremendous amount of work this was -- a hell of an achievement of the variety that makes most PhD applicati
      • Go read the articles and you'll appreciate what a tremendous amount of work this was -- a hell of an achievement of the variety that makes most PhD applications look like a 3rd grade book report.

        Unfortunately, it's an achievement akin to digging a large hole in the ground with a spoon. Someone wasted a lot of their time to do something useless in the most inefficient way possible.

  • Sucker! (Score:5, Funny)

    by bbh ( 210459 ) on Friday December 24, 2004 @09:49PM (#11179422)
    With that kinda money you could rebuild the sound stage they faked the first trip to the moon on!

    -bbh
    • With that kinda money you could rebuild the sound stage they faked the first trip to the moon on!

      Bahh! It would have meant more for mankind if he had built the stage for a mars mission. We've already been to the moon.

  • Now he has his own server slashdotted just before [Insert Religous Denomination Holiday Here]. Yup, he sure is the space geek who has EVERYTHING now!

    Take that those doing with less!
    • Now he has his own server slashdotted ... he sure is the space geek who has EVERYTHING now!

      Yeah, but running his server on his Apollo clone is cheating.
    • Christmas.

      Go ahead and say it. It's not a dirty word. It's not a filty word.

      Today is Christmas Eve, believe in Jesus or not. Tomorrow is Christmas, live in a Christian country or not.

      While something can be said for segregating the various holiday celebrations (Christmas, Haunukah, Kwanza, Yule, Saturnalia, and so forth), it's patently ludicrous to refuse to aknowledge each as they pass.

      And, in all fairness, refusing to mention the holiday is as offensive to Christians as any other cultural infringmen
      • I only do it to make the point of how silly the current PC trends are. Oh, and I am religous too to boot. Did you know people at NASA aren't supposedly allowed to say the actual words "Merry Christmas"?

        I believe Andy Rooney had a nice piece last year on the holidays and how literature referred to things more often as "Happy Holidays" or "Holiday Sale" instead of specifically mentioning Christmas.

        Christmas Christmas Christmas Christmas Christmas!

        Take that PC patrol! :)

        Besides as if it isnt bad enough tha

  • Your Palm Pilot is not radiation hardened. (Score:5, Informative)

    by gelfling ( 6534 ) on Friday December 24, 2004 @10:06PM (#11179455) Homepage Journal
    There are two reasons why spaceflight computers are relatively underpowered:

    Reliability under conditions your PC would fail, like radiation, shock, vibration, acceleration, heat and cold.

    Built to solve unique specialized problems for people who are not entirely computer expert.

    Navigation computers have to solve complex solid analytic geometry problems for people who are experts in solid analytic geometry but aren't experts in computers and don't have the luxury to spend lots of time to do that.
    • Palm pilot - $100
      Lead Box - $30

      Still woould cost (and weigh) less than the APC.
    • There have been anecdotal stories of astronauts using off-the-shelf laptops aboard the ISS with no issues to speak of.

      I'd google, but am on crappy dial-up this evening.
      • Yes consumer-grade equipment should work fairly normally *inside* the shielded ISS, but nobody in his right mind would trust the stuff for actual flight control systems.

        Its the difference between "aww shucks, there's a speck on my picture" and "retro-rockets failed to fire!"
    • main reason why apollo computer 'sucks' so much compared to computers of today is that it really IS _old_ in computer years. it's fucking old. it's older than old. they couldn't do anything better in smaller space. mars rovers had hardened powerpc's iirc - those weren't _that_ underpowered either.

      and seriously, you're speaking of "spaceflight computers" as if we had space marines going through the galaxy regularly(and that they were highly specialised computers less powerful than palm pilot, and that they
  • Where on earth are you going to find the vintage IC's for this thing? (Didn't RTFA). In the early 60s, it was either discrete logic using individual transistors and diodes, or really crappy RTL/DTL chips.

    • Re:parts? (Score:3, Funny)

      by node 3 ( 115640 )
      Where on earth are you going to find the vintage IC's for this thing? (Didn't RTFA).

      Well, RTFA you lazy sod! Had you done so, you'd have had your answer quicker than it took you to post the question.

  • Limits of simulation? (Score:3, Funny)

    by Tablizer ( 95088 ) on Friday December 24, 2004 @10:22PM (#11179497) Journal
    Can it simulate the part where the sensor loop queue was overloaded because they forgot to turn off the rendevous radar and the warning lights went crazy and Neil or Buzz wet his suit? (I have no official info that they did, but I bet at least one did but never told anyone.)

  • Finally (Score:3, Funny)

    by Lord Kano ( 13027 ) on Friday December 24, 2004 @10:39PM (#11179537) Homepage Journal
    A perfect way to add guidance to my Cruise Missile [slashdot.org]

    LK

  • Comment removed (Score:4, Insightful)

    by account_deleted ( 4530225 ) * on Friday December 24, 2004 @11:53PM (#11179727)
    Comment removed based on user account deletion

  • Apollo Guidance Computer - Disassembled (Score:3, Funny)

    by new500 ( 128819 ) on Saturday December 25, 2004 @05:21AM (#11180400) Journal
    . . .

    This is a link to a a partial tear-down of a Apollo Guidance Computer Logic Unit.

    http://klabs.org/mapld04/presentations/session_g/g 1007_hall_s.ppt [klabs.org]

    on slide three, N.B. the cost : $275,800.00.

    now i wonder could the guy in the story have afforded to deal with this as well :

    "In the early orbital missions before Apollo, NASA learned that the human animal, confined in a spacecraft for a week or so, was not as clean as might be expected from observations on Earth. This additional constraint had . . far-reaching impact . . All electrical connections and other surfaces had to be corrosive resistant . . . everything had to be hermetically sealed."

    eww!

    quote from http://klabs.org/history/history_docs/mit_docs/170 7.pdf [klabs.org] pages 4-5.

  • Documentation (Score:4, Informative)

    by Cryptnotic ( 154382 ) * on Saturday December 25, 2004 @05:26AM (#11180404)
    What's the most important thing about what this guy did?

    Documentation. He documented every step of the way everything that he did. It's something that's lacking in a lot of geeky projects and it's something that I commend this guy at doing an awesome job at.

  • Next: Build your own working replica of Little Boy (Score:3, Funny)

    by Muhammar ( 659468 ) on Saturday December 25, 2004 @05:56AM (#11180427)
    "Early gun-type designs are interesting. Because they're so simple, you can (if you like) actually understand the entire critical assembly process, from the start of fission to the propagation of the produced shockwave"

Slashdot Top Deals

Avoid strange women and temporary variables.

Close