Space MIAD Practice Test

What is the most common source of power for Earth-orbiting spacecraft?

1. Nuclear Power

2. Solar Power

3. Battery Power

4. Chemical Power

The correct answer is: Solar Power

Solar power is the most common source of power for Earth-orbiting spacecraft due to its abundance and efficiency in space. In the vacuum of space, sunlight is readily available and can be harnessed by solar panels installed on the spacecraft. These panels convert sunlight into electricity, which can then be used to power the spacecraft's instruments, communication systems, and other onboard systems. This reliance on solar energy is further supported by the fact that many Earth-orbiting missions, such as those conducted by satellites and the International Space Station, experience long periods of sunlight as they orbit the planet. Solar power systems can be designed to supply a continuous source of energy as long as the spacecraft is in sunlight, making them ideal for long-duration missions. In contrast, while nuclear power can provide a high energy density for specific missions, it is less common due to regulatory, safety, and implementation challenges. Battery power is typically used for short-term energy storage rather than as a primary power source, and chemical power usually refers to propulsion systems rather than the main source of power for spacecraft systems. Therefore, solar power stands out as the preferred method for generating electrical energy on most Earth-orbiting spacecraft.