Echo 1, the world’s first communications satellite, was launched by NASA on August 12, 1960.
Although it was the precursor of the multitude of satellites now circling the earth, Echo 1 bore little resemblance to its modern cousins.
Measuring 30.5 metres in diameter, the spherical, inflatable satellite weighed 68 kilograms and did not have a rigid skin.
Echo was designed by the Space Vehicle Group of the NASA Langley Research Centre and was constructed by General Mills of Minnesota.
Once in space, it was used as a passive communications satellite capable of reflecting radio and radar signals.
The first attempt to launch Echo into orbit failed in May 1960, when its Thor-Delta launch vehicle malfunctioned and sent the satellite into the Atlantic Ocean.
A second attempt was more successful and Echo reached its 1687-kilometre orbit on August 12 that year ,allowing a microwave transmission to be relayed from the Jet Propulsion Laboratory in California to Bell Laboratories in New Jersey.
An improved successor, Echo 2 – the last balloon satellite launched by Project Echo – was launched in 1964.
Echo was not the first artificial satellite sent into space.
That honour goes to the Soviet-designed Sputnik 1, which was launched in 1957.
Although Sputnik was equipped with an on-board radio transmitter, it was not placed in orbit for the purpose of sending data from one point on Earth to another.
As of 2016, it was estimated there were more than 2130 communications satellites in Earth’s orbit, in use by private and government organisations.
Unlike Echo’s relatively unambitious orbit, many of today’s satellites circle the Earth at a height of up to 35,700 km.
Modern communication satellites relay high-frequency signals around the curve of the Earth, allowing communication between widely separated geographical locations.
As well as telephone, radio and television signals, today’s communication satellites can relay broadband internet to inaccessible locations.