Forty years ago this Monday, my elder brother bounded up the stairs of our small, suburban home to tell me that "the man in the moon" had landed.

It was the dead of night, he could have been only about eight and, somewhere on the stairs, he'd got his facts mixed up and confused reality with our storybooks. It was hard to blame him: when I went downstairs, I could see that even my parents were struggling to accept that the hazy images of men in fat suits cavorting in a dust bowl were actually live pictures beamed all the way from the moon. When we found that out, we ran to the window to stare up into the sky to see if there was any sign of them, and we weren't too impressed when there wasn't.

To be honest, we weren't all that blown away by the muddy-looking pictures of the slow-motion astronauts either. Where were the phasers, the hostile aliens and the beautiful ladies in short skirts? Compared to Star Trek or Lost in Space, the reality of space travel seemed hopelessly dull, and you were tempted to ask the parents precisely why you'd been roused from your bed at this ungodly hour. To the grown-ups, though, it must have been a truly extraordinary and oddly hopeful moment, as the world was briefly united in wonder at our species' ingenuity, and by the boundless possibilities NASA's achievements seemed to throw up.

In a way, the events of July 20, 1969, turned out to be something of a false dawn. There would be other moonwalks, of course, but Armstrong's moment was to be the climax of the Apollo missions, and by the mid-70s the space project had been moved to the backburner as other, more pressing, human problems intervened.

So peripheral has it become, in fact, that to anyone under the age of, say, 35, the American Space Program is just a confusing and pointless waste of money, whose only result seems to be the odd unplanned explosion in the air above Cape Canaveral. But once upon a time, it seemed so much more than that, and the heady optimism of 1969 is fittingly recalled this Monday in a number of pro grammes dedicated to the first moon landings.

On UTV, Mission to the Moon: News from 1969 (at 10.35pm) looks back at how the landings were dealt with by the media at the time. In advance of Armstrong and Aldrin's descent, there was wide speculation about what would happen if they managed to land safely -- a big if. Observers wondered if the astronauts might sink into the moon's surface and never be seen again, or if some unforeseen element of the alien atmosphere would atomise them in a puff of smoke.

After the landings, the speculation would get even wilder, as hacks and pseudo-scientists predicted moon-mines within a generation and imminent manned space flights to Mars. (The moon is around 250,000 miles away from us -- the red planet, being a mere 35 million miles distant, may prove a slightly tougher nut to crack.)

Still, landing on the moon was a start, and in Moonshot: The Flight of Apollo 11, which is being screened on both RTE1 (10.30pm) and UTV (10.50pm), the extraordinary achievement of the astronauts and the team behind them is commemorated. A docudrama starring James Marsters, Andrew Lincoln and Daniel Lapaine, Moonshot concentrates on the three men at the centre of the Apollo 11 mission: Neil Armstrong, Buzz Aldrin and Michael Collins.

Collins, a witty, cultured man and the one who drew the short straw and remained in orbit while Armstrong and Aldrin hogged the limelight on the moon, later described himself and his colleagues as "amiable strangers", and the three men were only brought together by the accident of selection.

So much of what the three astronauts were expected to do on the Apollo 11 mission was a step into the dark. And while there had been previous lunar orbits, it was Armstrong who would have to undertake the first-ever extra-terrestrial approach and landing. The descent on the lunar mobile went anything but smoothly, with the guidance computer repeatedly triggering alarms and Armstrong arriving at the predetermined landing site only to find it strewn with boulders and unusable. He nearly ran out of fuel while trying to find a more suitable site, and the skill with which he accomplished all of this is often underestimated.

But their problems didn't end there. When Armstrong tried to lift off again, a circuit breaker in the ascent engine was knocked out, leaving them with no back-up. This meant that if the main engine failed, as they often did, they'd be stranded on the moon, and perish. With the world on tenterhooks (Richard Nixon had apparently prepared a substitute speech if things went horribly wrong), Michael Collins hovered in orbit wondering if he'd ever see his colleagues again.

A more intimate portrait of the Apollo 11 crew is provided by the excellent documentary In the Shadow of the Moon, which is being screened on Channel 4 at 10 past midnight. Directed by David Sington and produced by Ron Howard, the film examines the Apollo 11 mission and later space flights through the words and recollections of the remarkable men who undertook them.

The moon landing was the culmination of many years' preparation and sacrifice, and to the hand-picked fighter test pilots who volunteered for the Apollo project in the early 60s, space flight must have seemed a poor career choice. The prototype spacecraft of the previous Mercury programme had been notoriously volatile, and had an alarming tendency to blow up during take-off. But the Kennedy administration was hell-bent on success, and more than $24bn would be committed to the NASA project, which, at its peak, would employ more than 400,000 people.

With this kind of backing, progress was swift and the astronauts themselves were closely involved in designing the rockets that would carry them into space. A horrific gas explosion at a launchpad training exercise in 1967 killed three astronauts and nearly shelved the whole Apollo programme. But NASA persisted, and by early 1969 had successfully launched four manned missions, one of which had orbited the moon at close range. The stage was set for a lunar landing.

Recalling Apollo 11's juddering take-off, Michael Collins comments, "No, we were not scared. When something goes wrong, that's the time to get scared". Remarkably, nothing did go wrong, and everyone remembers Neil Armstrong's famous utterance in the moments before he set his foot on the lunar surface. According to Collins, however, his speech was not rehearsed. "It was like Neil," he says, "but deeper than I thought he'd come up with. Those words came out, and they were perfect."

Buzz Aldrin, meanwhile, was celebrating a minor milestone of his own. All of the astronauts wore special nappies while in space, and on the way down the module's ladder, Aldrin became the first man to relieve himself on the moon.

There would be five more successful moon missions, but after Apollo 17 the program was wound down, and since then no man has left Earth's near orbit. All the men who travelled to the moon were profoundly affected by the experience, some experiencing spiritual epiphanies, others struggling to cope with the emotional aftermath.

But all would find it hard to believe that they really had set foot on that distant orb one of them described as "the most beautiful desert you can imagine".

- Declan Cashin