How astronauts didn’t land on the moon

When the commanders of the six Apollo lunar landing missions took their lunar modules to the surface, they had a computer with them.

And, although in those days computers had tiny memories and operated slowly by today’s standard, they were cleverly designed and programmed machines. And it was important that they performed well…because if a LM computer crashed, the LM itself might crash as well.

Automated landing

The LM computer could actually operate the LM itself—fire thrusters, run radars, and navigate, getting the LM all the way to the ground. A software program, called P64, could land a LM without much astronaut input.

But the Apollo commanders: Neil Armstrong, Pete Conrad, Alan Shepard, Dave Scott, John Young and Gene Cernan chose NOT to use P64. They grabbed the stick and landed their spacecraft manually. Every last one of them.

Pilots, not just passengers

The Apollo commanders were, after all, pilots. To some degree, it was a macho thing. They wanted to operate and control their strange, complicated vehicle. Simply monitoring, and not flying, would be a foolish waste of a once in a lifetime opportunity.

A practical reason, too

Of course, though clever, the computer wasn’t perfect. For one thing, although NASA had pretty good photos of the moon, they weren’t high enough resolution to really completely check out a landing site.

While the LM crew was landing, they got the best-ever view of their landing sites. And, sometimes the view was troublesome. For example, the LM computer was taking Neil Armstrong towards a deadly landing in a field of boulders. Armstrong surely would have performed the landing manually regardless—but in his case, some manual control was absolutely necessary for a safe landing.

There’s more about the Apollo computers and the dividing of tasks between man and machine, in a book called Digital Apollo.