I'm going to play you a recording of a moment of great drama during the final stage of

the first mission to land humans on the moon.

A Polo 11 astronauts, Neil Armstrong and Buzz Aldrin, are squeezed into the cabin of

their spacecraft eagle and dropping at a rate of 120 feet per second.

It's a little short of halfway into their final 13 minutes of descent to the lunar

surface.

You can hear them and people in mission control sitting in a room a quarter of a million

miles away who are tracking eagle's descent and communicating with the crew by radio.

There are lots of different voices in NASA jargon in this, but listen out for the words

1202 and Pro-Rail.

Both Neil Armstrong and Buzz Aldrin call out 1202, which has flashed up as a row of numbers

on the limited display of eagle's on board computer.

They're not sure what it means, but they know it spells trouble, possibly serious enough

to force them to call off their historic mission and abort the landing.

Armstrong radios again to mission control, asking for help this time with uncharacteristic

urgency.

Back in mission control in Houston, all eyes fall on the solitary and youthful figure

of Steve Bales.

Someone will get to know well during the course of this podcast.

It's his responsibility to understand the computer, its alarms and to decide whether or

not the landing can still proceed.

The mission and very possibly the lives of the astronauts themselves depend on his

...