Friday, July 5, 2019

Final preparations for public display and demonstrations for the 50th anniversary of Apollo 11

Current Switch Module failed diodes

We will mill away all the rest of the potting on this module, drill out the 26 diodes that we haven't yet replaced and populate the module with suitable replacements. That will restore the erasable (traditional core RAM) memory to full operation.

Improving demonstration for spectators

While we can accomplish a lunar landing using just the AGC and DSKY, it requires the spectator to visualize quite a bit after they are taught to interpret various numbers displayed by the DSKY. We want to help visitors visualize what is happening so we worked on some improvements.

Mike worked on changes to his test monitor board, the one that plugs into the AGC test connector A52 and also runs with his FPGA replica of the AGC. He made corresponding changes to the NASSP plug-in for the Orbiter simulation, such that the simulation will use the real AGC (or FPGA AGC) rather than a virtual AGC inside the package.

Using this, we can interact with our AGC but see the results on the screen showing the inside of the Lunar Module and the view outside the windows. All the displays such as the altitude tape meter and FDAI flight director work properly. This gives a compelling simulation of the landing, with the engine thrust climbing, the view pivoting as the LM is maneuvered, and appropriate sounds emitting from the screen.

In addition to this, we will bring the LEGO Lunar Lander with LEDs placed in the RCS thruster jet openings and in the bells of the Ascent and Descent engines, driving them based on the pulses emitted by the software running in the real AGC during the mission. An Arduino interprets the pulses and controls the LEDs.

Organizing demonstration tour for 50th anniversary of Apollo 11

Now that the AGC is running well and we are prepared to demonstrate it supporting portions of the Apollo 11 mission, we have to set up public appearances for later this month. Having just completed booking the trip, I can share where we will be appearing.

At the start, we will bring the AGC to the home of the lead designer, Eldon Hall, and let him enjoy the sight of his masterpiece working again after all these years gone by. This will take place in Florida, after which we will fly up to the Long Island, NY area for the first public appearance.

We expect to give short talks and demonstrate landings at the Cradle of Aviation Museum, near LM 13 and CM 2 plus a LM Simulator and other Apollo era artifacts. This will occur on the 18th of July. We are waiting for the museum to define times more exactly.

The following day, July 19th will have us setting up in the MIT Museum in advance of our public appearance all day and evening of July 20th, the fiftieth anniversary of the landing on the moon. We will give talks and demonstrate portions of the flight including landings multiple times on the 20th. Once again, we don't have exact times yet.

That concludes the public demonstration portion of our trip, but we will have a chance to meet with many of the original programmers and designers from MIT and others who supported the success of the Apollo program.


  1. Best wishes for a great tour - you guys have certainly worked hard to make it all happen.

  2. Wow. Can't wait to see or read about all of that. Fantastic work Carl!

  3. I was one of the programmers of support software for Apollo. I'm still in the Boston area. When are you meeting with many of the original programmers. I'd like to be there.

    1. Hi Dick

      We were invited to the Apollonaut brunch on the 21st. I will email you with details.

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