Moon landing 50th anniversary: a joint initiative with CSIRO

It was May 6 1968 and Armstrong was at Ellington Air Force Base near Houston, learning to fly a craft like the one he'd land on the Moon.

When the first design studies began for such a vehicle it wasn't clear that a pilot would be able to control it.

To research flight problems and train astronauts, NASA and Bell Aerosystems built a series of flying machines soon nicknamed 'the flying bedstead'.

These craft lacked the upper structure of the real lunar module but mimicked how it would fly.

Armstrong had gained his pilot's licence at age 16, flown combat jets at 21 and been a test pilot for seven years before becoming an astronaut.

Flying was his life and unusual craft were nothing new to him.

He was the first astronaut to fly the 'bedstead' and described it as "a contrary machine and a risky machine, but a very useful one."

He'd flown it many times before that May day when problems with a couple of thrusters made him lose control of the craft and he had to bail out.

The vehicle was twice redesigned and tested but astronauts were not allowed to fly it again until June 1969.

Armstrong squeezed in eight more training flights just weeks before Apollo 11 launched.

His practice paid off when it came to landing the real lunar module on the Moon.

"I felt like I was flying something I was used to and it was doing the things that it ought to," he later said.

Despite that, the final descent to the Moon's surface "was the thing that I worried about, just because it was so difficult".

"That was far and away the most complex part of the flight."

As well as flying the 'bedstead' astronauts also trained in a ground-based simulator.

This mimicked all the systems of the real lunar module - engines, flight control, life support, navigation and communication - and was full of lights, dials, alarms and meters.

It had 678 switches and 410 circuit breakers and the training engineers could make any of them fail, faking a myriad of emergencies.

Armstrong and fellow astronaut Edwin 'Buzz' Aldrin both spent 400 hours training on the simulator and by the time they left for the Moon they knew the lunar module inside out.

The machine they would fly to the Moon's surface looked like a giant insect.

It had 18 engines and eight radio systems, and was crammed with fuel tanks, life-support systems and instruments.

To save weight there were no seats. The astronauts flew standing up, tethered in place.

The walls were no thicker than a few sheets of paper in some areas but they were made of high-strength aluminium supported by ribs and struts, and draped with materials to insulate and protect them.

The lunar module was too fragile to test on Earth so Apollo 9 and 10 put it through its paces in space.

When Apollo 9 commander James McDivitt first saw it he burst out, "Holy Moses, we're really going to fly that thing?"

But he and a fellow astronaut did, rehearsing manoeuvres for Apollo 11.

Armstrong and his crew named their lunar module Eagle after America's national bird.