Radioisotope Thermoelectric Generators (RTGs)

Radioisotope Thermoelectric Generators (RTGs)

How It Works

Radioisotope Thermoelectric Generators (RTGs) are reliable, lightweight, and compact power systems used primarily in space missions. These generators produce electricity by converting the heat released from the natural radioactive decay of plutonium-238 (in the form of plutonium oxide) into electrical power. The process involves the following key components:

Plutonium-238 Fuel: The radioactive decay of this isotope produces significant heat.

Thermocouples: These are special solid-state metallic junctions that generate electricity when exposed to a temperature gradient. The heat from the plutonium-238 creates a large temperature difference between the hot fuel and the cold space environment, which the thermocouples convert into electrical current.

Its use:

Cassini Mission: The Cassini spacecraft utilized three General Purpose Heat Source (GPHS) RTGs to generate electrical power for its scientific instruments and onboard systems.

MMRTG: The Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) used on Mars by the Curiosity rover is another example of RTG application.

Applications and Safety:

RTGs are particularly valuable for missions where solar power is impractical, such as in deep space or on planets with weak sunlight. They have been used in more than two dozen U.S. space missions since 1961. Despite being referred to as “nuclear batteries,” RTGs are not fission reactors, and the plutonium used is not suitable for nuclear weapons.

RTGs provide a dependable power source for long-duration space missions, enabling scientific exploration and data collection in harsh and remote environments.