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Apollo On Board Computer Emulator

Posted by michael on from the powerful-geekiness dept.

frankk74 writes "For those of you interested in Historical Computing and the Apollo manned spaceflights Ron Burkey has created a open source emulation of the Apollo Guidance Computer called vAGC. I use it as my desktop clock of choice. Note it only keeps mission time so after 24 hours you have reset the time :-). P.S. Another cool Apollo toy free and payware can be found here."

6 of 166 comments (clear)

  1. Re:12-bit Instruction set by hughk · · Score: 4, Informative

    Not really, and it had an excellent reputation for real-time work. The thing is when NASA were shopping for processors a long time before the landing, the PDP-8 didn't exist in the compact form. By the time of the first landing it certainly did, but it was already too late. The PDP-8 and later the PDP-11 then just swept through the world of real-time computing.

    --
    See my journal, I write things there
  2. Orbiter by 0123456 · · Score: 4, Informative

    "then integrate the whole thing into Orbiter."

    Already being worked on:

    http://mysite.wanadoo-members.co.uk/marui/orbite r_ agc.jpg

  3. nope Re:Disaster waiting to happen by WolfWithoutAClause · · Score: 4, Informative
    In order to have a 'level' to measure they had to create an artificial gravity inside the tank by swirling the contents with an internal electric motor and a blade.

    They didn't use artificial gravity to seperate the LOX; quite the opposite.

    In fact, in zero gravity LOX tends to divide up into regions of gas and liquid. If the gas happens to float past the sensor, then they get an incorrect reading of the density, and hence they don't know how much is in there. This was a big problem on previous flights. Stirring the tank mixes it all up and makes it the same density; allowing a reliable reading to be taken.

    you have several pounds of highly combustible aluminum and graphite parts

    Aluminum, particularly bulk aluminum is *not* combustible in LOX. It's used on the Space Shuttle main tank fer heavens sake!

    Graphite can't really burn either; for it to burn it needs to reach ~3000K, and the LOX is pretty keen on it not reaching that temperature.

    LOX only really explodes in contact with greases- it's soluble in them, and they form a contact explosive.

    and you have a DC motor with brushes sparking up a storm

    Provided the brushes are carefully chosen, this need not be a problem.

    That's not actually what caused the explosion anyway.

    During testing a relay welded itself shut due to incorrect voltages. In flight, the wiring overheated- and the insulation burnt in the LOX. That caused the LOX tank to overpressure, and it blew away half the side of the vehicle.

    --

    -WolfWithoutAClause

    "Gravity is only a theory, not a fact!"
  4. Parent is informative, deserves upmod by Beryllium+Sphere(tm) · · Score: 4, Informative

    In addition, the incorrect voltages during testing were the result of failed communication between the contractor and NASA, a spectacular example of why the paperwork is important.

  5. Draper Labs built the AGC by dswartz · · Score: 4, Informative

    I would just like to point out that Draper Labs in Cambridge, MA (the company I work for) built the AGC. An exact replica of the real AGC sits in our Simulation Lab.

  6. Notes on compiling by crucini · · Score: 4, Informative

    I didn't immediately succeed with the author's instructions. Here's what worked for me:

    cd yaAGC
    ./configure
    make
    sudo make install
    cd yaDSKY
    ./configure
    make
    sudo make install
    yaAGC --core=Validation.bin --debug
    In another window, still in the yaDSKY directory: yadsky --cfg=src/LM.ini
    (Note lowercase yadsky)
    Congratulations, Ronald. Pretty cool. Does the contrast on the LED display have to be so low? The background is very light.

    Am I the only one here who actually tried the program?