You're about to hear a crucial moment in the 13 minutes before the landing of Apollo 11.

Right now, eagle carrying Armstrong and Ordin is coming up on 8 minutes into its powered

descent, taking them towards the surface of the moon.

At this point, Armstrong and Ordin can't actually see the moon, because the lunar module

is flying sideways across the lunar surface, and inside the astronauts are lying on their

backs, looking through a pair of small triangular windows with the star-filled skies above.

Right now, someone else, or rather, something else, is in the driving seat.

When they say P64, they're talking about a program that's running on the lunar module's

remarkable onboard computer, which at this point is doing all the flying.

Here's Charlie Duke telling us what that felt like during his landing on Apollo 16.

You're coming down on this computer's finite, but you don't see the moon because the

windows are pointed up in space.

So at 2,000 meters, 7,000 feet, the vehicle pitches over it into a landing program, and you

can see the landing spot for the first time.

And the computer told you, if you don't do anything, you're going to land at this spot.

P64, okay, they got 64.

The astronauts were amongst the best pilots of their age, but without the lunar module's

unique computer and elegant programs, landing on the moon would have been impossible.

Each position, too, all flight controllers, 20 seconds to go, and I'll go for landing.

We choose to go to the moon!

Cap time, we're go for landing.

We go using your go for landing, over.

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