In the last seven episodes we've dug into the stories of the people, technology and

events that made Apollo 11's final 13 minutes of descent possible.

In the next two we want to pull all of that together. We want to take you through the first landing on the moon from beginning to end and through the moments where it teeters on the edge of failure or worse.

The final 13 minutes were a leap into the unknown. Nobody was confident the landing would succeed. Apollo computer programmer Don Isles.

We were far from certain that we were going to end up with a successful landing. We were pretty certain that we were going to end up with a live crew about trying this for the first time.

I think we certainly had some apprehension about whether it was going to come up successfully.

In Houston's mission control, flight controllers like Jay Green shared these doubts.

We were doing something that had never been done before and we anticipated aborting. Nobody on the team believed that we'd make it down the first time. I don't think anybody did. Yeah, it was intense.

Neil Armstrong knew what they were all up against.

It's one of the most complex part of the flight. The systems were very heavily loaded at that time. The unknowns were rampant. The systems in this mode had only been tested on earth and never in the real environment.

There were just a thousand things to worry about in the final descent. It was the thing that I agreed about because it was so difficult.

We choose to go to the moon. Cap time, we're go for landing. We go to your go for landing over.

We're getting on the 12th floor through the program alarm. Over that 18 foot, we're going to make it a thing.

Roger. No level. 60. 60 seconds. We've had chest down. We got me a down, ego.

I'm Kevin Fong and from the BBC World Service, this is 13 minutes to the moon.

Episode 8. We're go for powered descent.

We join the action in the final hour before the Apollo 11 landing.

At this point, both spacecraft are behind the moon out of radio contact with the earth.

Michael Collins in the command module Columbia is in a 60 mile high orbit, whilst Neil Armstrong and Buzz Aldrin in the eagle are heading downwards on a gently sloping path.

But it won't be long before both craft emerge over the lunar horizon and contact is reestablished.

In mission control, the tension is mounting for flight director Jean Kranz and his team of flight controllers.

The adrenaline. I mean, just really was no matter how you tried to hide it, the fact is that you were really starting to pump.

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