How do you choose the best power source for your spacecraft mission?

1 Power sources for spacecraft

There are two main types of power sources for spacecraft: solar and nuclear. Solar power relies on photovoltaic cells that convert sunlight into electricity. Nuclear power uses radioisotope thermoelectric generators (RTGs) or nuclear reactors that produce heat and electricity from radioactive decay. Both types have advantages and disadvantages, depending on the mission characteristics.

2 Solar power advantages and disadvantages

Solar power is the most common and widely used power source for spacecraft, particularly for those in the inner solar system where sunlight is abundant and reliable. Solar power is clean, renewable, scalable, and relatively low-cost. However, there are some limitations to consider. The power output depends on the distance from the sun, the angle of incidence, and the solar activity cycle. Solar panels can be damaged by micrometeoroids, debris, and radiation. Additionally, they add mass and surface area to the spacecraft, which can affect its aerodynamics and thermal control. Lastly, a spacecraft needs batteries or other energy storage devices to operate during eclipses or periods of low illumination.

3 Nuclear power advantages and disadvantages

Nuclear power is the ideal choice for missions that demand high and consistent power levels, or that take place in regions where solar power is inadequate or nonexistent, such as the outer solar system, the polar regions, or the dark side of the moon. Nuclear power is independent of the sun, dependable, and long-lasting. Despite its advantages, nuclear power also has some drawbacks, including limited power output due to the availability and performance of radioisotopes or reactor fuel, complexity and expense to design, build, and launch, safety and environmental risks during launch and operation, and excess heat that needs to be dissipated or used efficiently by the spacecraft.

4 Power optimization strategies

When selecting the best power source for your spacecraft mission, it is also essential to optimize the power consumption and distribution of your spacecraft systems and components. This will ensure they perform as expected and do not waste or overload the power source. To do this, you can design your spacecraft to be lightweight, compact, and aerodynamic to reduce power requirements. Additionally, select efficient, reliable, and compatible components to minimize losses and failures. Balancing your spacecraft power budget is necessary to allocate the power resources among different functions and subsystems according to their priority, frequency, and duration. Finally, monitor and control your spacecraft power status to detect and correct any anomalies or deviations that affect the power generation, storage, or consumption.

5 Power source selection criteria

When determining the best power source for your spacecraft mission, several factors and trade-offs need to be evaluated and compared. Mission objectives, scope, and duration will define the power needs and expectations for the spacecraft functions and experiments. The mission destination, trajectory, and environment will determine the power availability and variability for the spacecraft location and orientation. The mission cost, risk, and feasibility must be assessed in order to determine the power affordability and reliability for the spacecraft design and launch. Finally, the mission impact, legacy, and sustainability should be considered in order to understand the power implications and consequences for the spacecraft operation and disposal.