Power Switches

Question 1

Through what system can spacecraft loads voltages and currents be monitored, and the loads switched on and off?

Answer 1

Telecommand system

Question 2

What is the role of power switches on the spacecraft?

Answer 2

To protect spacecraft loads and subsystems from current surges resulting from short circuits or SEE

Question 3

What four methods are outlined for power distribution?

Answer 3

• Hard wiring
• Fused
• Current limiter
• Power switches

Question 4

What are the two different current limiter types mentioned?

Answer 4

• Fixed Current limiter – current remains constant up to a cutoff voltage where it drops
• Foldback Current limiter – current increases linearly with voltage up to a cutoff voltage

Question 5

What does the diagram look like for a centralised power sub system?

Answer 5

• SA ->BCR module -> voltage regulation stage -> power distribution module
• Telemetry commands feed into a BCR logic control and the power distribution module
• Battery connected between regulation stage and power dist.

Question 6

What does the diagram look like for a distributed power sub system?

Answer 6

• SA -> BCR module -> power distribution module -> unregulated power bus -> subsystem voltage regulation

Question 7

What does the array regulator do?

Answer 7

Switches in and out sections off the solar array depending on power requirements

Question 8

What happens to the power drawn when the solar array section is switched out?

Answer 8

it is grounded via the shunt dump module