Electrical Power Subsystem (EPS)

The EPS serves as the sole generator, handler, and distributor of power aboard the PULSE-A spacecraft, and its design is driven by several high-level functional requirements.

Table 1. EPS Functional Requirements
Level	Req. Number	Requirement
Functional	EPS-01	The EPS shall comply with all requirements in the most recent version of the CubeSat Design Specification.
Functional	EPS-02	The EPS shall generate energy from the sun.
Functional	EPS-03	The EPS shall provide energy storage.
Functional	EPS-04	The EPS shall distribute power to all Satellite subystems.
Functional	EPS-05	The EPS shall inhibit power to the Satellite at two levels while contained within a deployer.
Functional	EPS-06	The EPS shall be capable of providing power to the bus using only solar generation.
Functional	EPS-07	The EPS shall have an external charging port for its energy storage device.

The requirements necessitate the use of three main blocks: Power Control & Distribution Unit (PCDU), the Battery Board, and the solar panel assembly. The PCDU manages the distribution of all power to the spacecraft and the interface between solar panels and batteries, and is managed by an onboard processor.

Table 2. EPS Performance Requirements
Level	Req. Number	Requirement
Performance	EPS-08	The EPS shall generate 11 Wh < Energy < 80 Wh (TBR) of energy during each orbit.
Performance	EPS-09	The EPS shall provide 13 Wh (TBR) < Capacity < 80 Wh of energy storage.
Performance	EPS-10	The EPS shall provide 7 W ± 2 W (TBR) average power during entire mission operations after initial boot-up.
Performance	EPS-11	The EPS shall be designed to provide 32 W ± 5 W (TBR) maximum continuous power during eclipse.
Performance	EPS-12	The EPS shall be designed to provide 50 W ± 10 W (TBR) peak power draw during deployment of external components.