Nigeria has sponsored or co-sponsored six satellites, of which only two are currently operational. One of them is functioning even though it has passed its expiry date, according to the director-general of the National Space Research and Development Agency.
A satellite can be said to have expired by design or operation. Like every other machine, satellites are designed with a projected expiry date or calculated life expectancy. Beyond this period the operational survival is not guaranteed by the manufacturer.
Operationally, a satellite expires when any of its critical components suffers enough damage or is degraded to the point of causing system or major sub-system failure.
A satellite is made up of different components. These include a protective box, an onboard computer for receiving, processing, and transmitting signals, as well as solar array panels, batteries, and fuel for energy. Any problem with any of these can translate to the operational end of a satellite.
Unlike cars or aircraft, satellites don’t really need fuel for their daily orbital operation. They mostly rely on solar-powered batteries. However, the fuel is relevant in supporting satellites to maintain orbital trajectory and conduct maneuvers when required. Hence, when a satellite runs out of power it is usually switched off to avoid a collision.
Beyond these, an accident or an attack can end the operational life expectancy of a satellite. Space is a very harsh environment, which is becoming increasingly congested.
This means it’s important that satellites are designed to the highest engineering quality. Nigeria currently has a communication satellite, NigComSat – IR, and an Earth observation satellite, NigeriaSat -2, in operation.
The communication satellite was designed to last for 15 years (2011-2026) in orbit. The Earth observation satellite is surviving beyond the projected life expectancy of seven years (2011-2018). This is a testament to the quality of its engineering, thanks to its manufacturer, the UK-based Surrey Satellite Technology Limited. A favorable host environment would also be a factor.
Nigeria has made huge investments in satellite technology. More than $1 billion have been set aside for this purpose over the last two decades. This included about $450 million spent on two communication satellites and four Earth observatory or research satellites.