In 1960, the USA’s space agency NASA launched a balloon-shaped satellite, Echo-1, (Photo, above). It took up an orbit comparatively close to Earth, about 1600 kilometres up. Once in position it grew to a diameter of 30 metres (100 feet), by inflating its own balloon made of a plastic material called Mylar.

The Mylar had a reflective coating of aluminum, Radio signals beamed from Earth to Echo-1 bounced off the satellite’s surface and could be received on the Earth far from the original transmission, NASA’s Echo-1 successfully transmitted voice, music and pictures between the USA and Europe, but in 1968 it disappeared from the sky.