In order to provide this power to the satellites, they will each carry a Plutonium (IV) Dioxide radioisotope thermoelectric generator (RTG). This power system will eliminate the need for batteries, which require heaters and have a limited number of recharge cycles, as well as allowing seamless performance when the satellites pass through shadows. Additionally, solar panels were foregone as a design choice because the panels would be approximately four times the size of an Earth-based satellite due to the decreased irradiance provided by the sun at Mars’s orbital radius. Likewise, RTGs have a much larger lifetime compared to solar panels because solar radiation and micro meteorites will degrade the performance over time.
Power Budget
Device
Power (W)
Earth Link Transmitter
30
Satellite Link Transmitter
20
Receiver Link Transmitter
20
Computer System
75
Attitude Control System
150
Sensors
75
Miscellaneous Electronics
50
20% Overhead
84
Total
504
The power budget shows the power needed to conduct satellite operations. One factor of the RTG is that the plutonium has a half life of 87.7 years. This means that its power output will deteriorate over time. Therefore, a larger RTG capable of producing 590 watts at launch will be included in the design. This way, the satellite will be capable of generating the required 504 watts after 20 years.
