Space age reaches 50-year milestone

The dawn of the space age broke 50 years ago today when a bleeping aluminium sphere the size of a basketball became the first man-made object to orbit the Earth.

The launch of the Soviet satellite Sputnik 1 took the world by surprise and sparked the global space race.

Since that day on October 4, 1957, men have walked on the Moon, robot rovers have crossed the deserts of Mars, and unmanned spacecraft have visited Venus, Jupiter and Saturn.

Two of Sputnik's heirs, Voyagers 1 and 2, are now heading towards the edge of the Solar System after 30 years in space.

Before the end of the century astronauts are expected to set up bases on the Moon and walk on Mars.

Other legacies of Sputnik include the International Space Station and a wealth of technical and scientific achievements that have changed the way we live.

Television pictures, telephone calls and email messages beamed from satellites have turned the world into a global village.

Space technology has also spawned a host of spin-offs, including satellite navigation, miniaturised electronic components, medical imaging equipment, smoke detectors (first used on the orbiting space station Skylab) and self-adjusting sunglasses.

Weather watching from space has revolutionised forecasts, and allowed the effects of climate change to be monitored.

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