Apollo 11 Flight Director Gene Krantz – “How To Park On The Moon”


Apollo 11 Flight Director Gene Krantz Explains How To Park On The Moon.

Gene Krantz: The “1201” and “1202” were two program alarms we learned about in our final day of training for the Apollo 11 team deployed to the Cape [Kennedy]. We made a wrong call in simulation, and didn’t understand the nature and significance of the alarms. So we sent the team back to work overnight to come up to speed with implications of the alarms on the mission and the LM [Lunar Module] guidance computer during the process of going down to the Moon. The amazing thing was this was our final training run. Normally final training is a graduation ceremony, but the instructors didn’t treat it that way. We thought we weren’t quite ready. When the real mission came along, we had come up to speed on what the program alarms meant. And, right in the battle of getting the crew down to the surface, we saw the alarms. We knew exactly what to do, continued the mission and landed on the Moon with less than 17 seconds of fuel remaining.

JC: In the Apollo movies, everyone looks to one young guy for a signal whether to abort or continue when those alarms come on.

The average age of my entire team at Mission Control was 26. That was a young man by the name of Steve Bales. He knew exactly what to say. We were all glued to our own consoles because we had a lot of other problems at the same time. We knew we were going to be landing long, we had trajectory changes, we were waiting to get our landing radar in. We also had a minor electrical problem – communications weren’t all up to snuff – so we had our hands full.


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  1. This is probably off topic… Also most of the armed forces of the USA are also under that same age right now. USA armed forces are the size of what maybe a fortune 50? company, all ran by mostly 19-22 year olds. The officers and management staff a very small percentage of positions. –food for thought

  2. The average age of Mission Control might have been 26, but the average age of the astronauts who walked on the moon was 40. The Apollo missions where a combination of knowledge kept on earth and experience in the field (or spaceship).

  3. Those 1201 and 1202 alarms actually resulted in a full restart of the computer… And the OS was smart enough to restart the critical programs after the OS restart and put them right at the point in their execution that they needed to be. Heck of an OS feature given the year and how limited the computer was actually… And, in that case, restarting (and not restarting the non-critical functions that had caused the errors) actually solved the problem. So the mission could safely continue. Worth a read:

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