The Electrical Power Systems [EPS] team is responsible for the generation, storage and distribution of
electrical power onboard the satellite. To cut costs and leverage industry experience, an attempt is
being made to ensure as many components in our design as possible are available off-the-shelf.
The satellite EPS can be divided into two sections: power generation and storage, and power
distribution. This division occurs in order to conform to competition guidelines as laid down by the
Canadian Satellite Design Challenge [CSDC]. The guidelines state that during launch, all components in
the satellite must be disconnected from any power source. In addition, due to the fact that the satellite
will be physically inaccessible for maintenance for the duration of its mission, both circuits will be
designed to eliminate all single points of failure.
Power Generation and Storage
In order to mitigate the possibility of the satellite losing power while tumbling (e.g. directly after being
released into space before its orbit has been established), solar cells are to be placed on all six faces of
the satellite. This configuration will help to ensure that, while the satellite is on the sun-facing side of
the earth, some amount of electricity will always be being generated. The difficulty with this design is
that, during normal operational modes, sunlight will be hitting the different sides of the satellite at
different angles and, therefore, the cells on each side will be producing different amounts of power. The
optimal solution lies somewhere between adding components to the circuit to match the voltages
coming off each side, thereby losing more power to component inefficiencies and to powering the
components themselves, or just combining the mismatched voltages and losing some to internal
dissipation. Once the electricity has been generated, it will be stored in batteries until such time as it is
The distribution of power to the satellite has to be carefully budgeted, since the amount which can be
produced and stored at a given time is very limited. Since we are currently in the early phases of a new
mission, the budget is currently being reworked to account for our new propulsion system, which
requires a lot of power.