EPS

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

needed.

 

Power Distribution

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.

WatSat © 2017