A spacecraft is delivered in orbit by a launcher which performances are constrained by its mass. It consists of a platform and a payload. The platform maintains the spacecraft at the right orbital position with the right attitude, generates power from solar panels or from energy stored in batteries, and dissipates thermal power. The payload receives radio signals transmitted by transmitters located on ground as part of the RAN or from the UEs, and transmits after amplification, frequency conversion, and possibly signal demodulation, routing and remodulation. The payload of the spacecraft is power limited, and it would not be economically viable for a satellite network designer to offer such margins that would allow a satellite signal to penetrate directly into buildings.
To optimise the delivery of information the radio coverage of the satellites is reduced with respect to the geometrical coverage thanks to antenna design optimisation. Antenna steering, switching or routing between beams can also be used to achieve coverage flexibility.