The Satellite Centre at Surrey has 8 microsatellites that orbit above the equator at 970 km above the Earth. They are equally spaced and their 'footprints' overlap to ensure the whole Earth is covered. Find out more about six of our missions...

Some satellites are in Low Earth Orbit (LEO) at a height of only about 700 km above the Earth's surface. They orbit over the pole once every 100 minutes approximately and can see a different segment of the Earth as it spins beneath the satellite. All of the satellites are continuously monitored by Mission Control at Surrey Space Centre as they pass over head at 7.5 km/s. This makes sure each one is in the correct orbit and attitude (orientation) and allows the scientists to download any data the satellite has taken in its journey around the earth. Each pass lasts only 10 - 20 minutes before the satellite is again out of reach.

Communications satellites such as those that transmit television signals, are in geostationary orbit. They go round the equator once in 24 hours. This is how they remain above the same spot on the Earth all the time. These travel much more slowly than LEO satellites and are about 36000km above the Earth's surface.

780 km circular orbit, 98 degree inclination

UoSAT-3 has far outlived its original design life of three years and was 'retired' from active service in 1999. As the spacecraft is still operational, engineers switched UoSAT-3's communications links from digital store-and-forward communications to an FM voice transponder mode for use by international amateur radio operators.

Surrey's UoSAT-3 Microsatellite Assists Indian Earthquake Relief Teams

28th February 2001 Amateur radio operators helping with earthquake relief operations in India, used small satellite built and launched 11 years ago as the primary link to the outside world after the earthquake while many telephone services in the earthquake zone were out of action.

Radio amateurs Guru Rao and Sandeep Shah exchanges information via an FM voice transponder onboard the UoSAT-3 microsatellite.

Another Bangalore radio amateur and a former UNESCO official, Chandru Ramachandra, drove some 1700km to Bhuj carrying a medical team and 400kg of equipment and supplies, setting up a satellite ground station to establish a link between the earthquake site and Bangalore using UoSAT-3.

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