Sputnik 1, the world's first satellite, getting ready for its trip to space.
Image: NASA
Source: NASA
Thurs 4th October was the 50th anniversary of the launch of Sputnik.
Put into space by the USSR, Sputnik was the world's first satellite.
About the size of a basketball and weighing 83kg, it took Sputnik 89 minutes to orbit the Earth. It remained in orbit for 3 months, before being destroyed when it 'fell' into the Earth's atmosphere.
Many people claim to have seen Sputnik but the satellite itself was quite faint, pushing the limit of the naked eye. It is likely that observers were seeing the much brighter spent rocket that originally launched the satellite.
Sputnik carried a radio beacon which emitted regular beeps, which could be picked up using a simple radio receiver.
Sputnik changed the world. Nowadays satellites are part of our everyday lives. We use them for communication, entertainment, navigation and data collection (eg. weather, environmental and astronomy). There are about 800 active satellites and a few thousand decommissioned satellites currently orbiting the Earth. There's even one satellite with human presence - the International Space Station.
There's also a lot of space junk orbiting the Earth. Estimates of this run into the 10 000s, including such objects as hatch covers, rocket bodies, lenses, payloads that have disintegrated or exploded and even objects 'dropped' during the operation of manned spacecrafts.
Eyes on Earth, a new exhibition on satellites will open at Scienceworks this December.