KEN MacTAGGART

Fifty years ago today, as an excited four-year-old, I stood on Dorchester Avenue in the west end of Glasgow staring at the sky with my father. We were looking for Sputnik, the world's first artificial satellite, the launch of which had just been announced to the world. Its signature "beep beep beep" was heard on every radio station.

Unknown to me, some 1600 miles away in a Moscow suburb, teenager Alexander Alexandrov was doing the same. With no street lights and a clear sky, he saw "an energetic point of light" moving steadily across the heavens - a sight that eluded those of us under Scottish clouds.

The world was seized with excitement - and in the west not a little fear - at this Cold War demonstration of Soviet technological power. Sputnik was closely followed by the first animal in space, the dog Laika, but the Russians drew a veil over the end of that story. Later it emerged that Laika was asphyxiated when her oxygen ran out. There had been no plans to bring her back.

The following year the Americans, stung into action, finally got their minuscule Explorer satellite into orbit. But the Russians continued to leap ahead. Their Luna 2 probe hit the moon in 1959, scattering Soviet pennants and red flags in the dust. Its successor flew around the moon and photographed the previously unseen far side.

By now, manned space flights were being feverishly planned - and the Russians won again. In April 1961, Yuri Gagarin became the first man in space, and was sent on a triumphant world tour afterwards. Alexei Leonov was the first space-walker, floating outside his craft in 1965. Now a sprightly 73-year-old, he recently spoke to fascinated Scottish school-children about his experiences.

Slowly the Americans strove to catch up, practising space docking and longer flights. Then came 1967, a year of tragedy for both competing nations. First, three Americans died trying to open the hatch of their flaming Apollo 1 capsule when it horrifically caught fire on the launch pad. Then the Soyuz craft piloted by Soviet cosmonaut Vladimir Komarov plunged out of control, parachutes twisted and useless, into the Ural Mountains.

The Russians and Americans made huge strides to recover from their disasters, and by the autumn of 1968 they were each reaching for the moon again. The Soviets had sent two empty capsules around the moon and recovered them safely, but they weren't quite ready to put men in them.

The Americans saw their chance. Hastily re-arranging their programme, they sent three men to orbit the moon in Apollo 8. The world gazed in wonder at fuzzy black-and-white TV pictures of the earth's receding ball, and the colour pictures of "earthrise" they brought back home. The moon race was effectively over.

Three flights later, in July 1969, Neil Armstrong stepped on to the dusty Sea of Tranquillity with the immortal words: "That's a small step for a man, one giant leap for mankind."

Five other US moon landings followed, and the Soviets built and occupied a succession of space stations. The first Space Shuttle went up in 1981, and today the Americans and Russians co-operate on the International Space Station, regularly flying to and fro in each others' craft. The earth itself is continually scrutinised by scientific satellites which have become a part of daily life, reporting on the weather, oceans, land use, vegetation and climate change. Unmanned robots have also landed on Mars, Venus, asteroids and Saturn's moon Titan, with pictures sent back of desolate alien worlds. Probes visit every corner of the solar system, and craft are currently en route to Pluto, Mercury, the asteroid belt and comets. The 30-year-old Voyager 1 is mankind's most remote emissary, still sending back its feeble signals 9.6 billion miles from home, and on the verge of leaving our solar system for interstellar space.

In the future we can expect more robotic exploration of the planets, and men and women to return to the moon. But no future achievement is likely to compare with the changed world-view that has come from mankind leaving the home planet these past 50 years.

That Russian teenager and I met last month at a conference organised by Careers Scotland in Strathclyde University, where we exchanged our boyhood Sputnik stories. Alexander was inspired by his country's technological "first", and went on to become a cosmonaut. He flew twice to Soviet space stations, spending 309 days in orbit.