LANDING STATION & PROPULSION

Power Subsystem

Below in Table1 are the various electronics that are present within the rover. These power consumptions must be considered in order to design the subsystem. Note that not all of the listed components will be active at the same time. For example the antenna motors and the ramp motors would only be powered upon landing on the moon. The antenna motor would just be used for initial aiming at the moon and the ramp motor will only be used once to open the exit for the rover. The command and data handling (C&DH) unit is the only system that would be fully powered from the initial departure from the carrier until power down during lunar nights.

Component

Power Consumption (W)

Ant Motor

11

Ramp Motor

10

Camera

6

C&DH

20

Thrusters Firing

30

Communication Systems

78

Table1:Power Consumption

Solar Cells

Not much power is used during the travel from the carrier to the moon since communications to the lander would be done through the carrier which is closer. One firing of each thruster would require approximately 5W though not all eight thrusters would be fired at the same time. From the power consumption table the largest power is consumed once the lander is stationed on the surface of the moon. Approximately 100W is needed resulting in the Si-solar cell of Table2. The self-adjusting solar panels are mounted on top of the lander. The Solar Panel used for our design, can be found HERE.

Power needed (W)

Peak W/ft²

kg/ft²

m² needed

Weight (kg)

100

17.95

1.36

0.52

7.65

Table 2: Solar Cell Properties

Battery

During the lunar nights the solar cells cannot generate power there for the lander must rely on the battery. All electronics would be turned off except the processing unit and the communication systems which would be in power down mode. A battery size of 700 Watt-hours would be needed to support the power down. Lithium ion batteries were chosen for its high weight efficiency. Ten units of the Li-battery in the link above will be used. The Battery used for our design, can be found HERE.

POWER DISTRIBUTION

To distribute the power to the various electronics a 28V dc power bus is used. The power management system used for our design can be found HERE.

HEAT DISSIPATION OF ELECTRONICS

Temperature of conventional electronics will be controlled by coating the outer surface. Coating includes various tapes and paint. The coat will balance the heat absorbed and heat radiated. Electronic equipment with requirement of more than 50W of power will special heat pipes, otherwise increasing the thickness of the mounting panel is sufficient to dissipate the heat [1].

[1] J. R. Wertz and W. J. Larson, Space Mission Analysis and Design. Colorado Springs: Kluwer Academic Publishers.