In this way, when SES first brought DTH satellite TV to Europe it was not known what the demand for the services would be and therefore how many transponders would be required.
[5] Another key benefit of co-location as exercised by SES is that of reliability of service, and it is a crucial defence against satellite failure.
SES maintains its co-located satellites within an imaginary 150 km cube in space, centred on the notional orbital position.
[6] All geostationary satellites are influenced by gravity of the Earth, the Moon and the Sun, and tend to drift from their initial orbital position.
They are maintained on-station with on-board thrusters fired under the control of the operations centre on the ground.