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Powering Space: Radioisotope Thermoelectric Generators

Thermoelectric Radioisotope Generators Power Space

Space exploration is a topic that has piqued the world’s interest since Apollo landed on the moon in the 60s. There are so many questions around space travel, the preparation, mission details and much more. But have you ever asked yourself how these missions are powered?

Lucky for you, we’ve just become resident experts in powering spacecrafts. Missions, past and future, have been made possible through the use of radioisotope thermoelectric technology - an incredible source of energy responsible for powering the most historic voyages of our time.

What Is Radioisotope Power?

Radioisotope power systems generate heat by converting a radioactive isotope, plutonium-238, into energy. Radioisotope power is an ideal source of energy because it doesn’t use actual moving parts that could potentially fail or wear out.

There are two main types of power systems that use this element in space missions.

  1. Radioisotope Heater Units (RHU): Small units used to keep parts of the machine heated so they don’t freeze in space
  2. Radioisotope Thermoelectric Generator (RTG): Large generator used to power the entire machine

In addition to the presence of Pu-238, these generators are made possible by using thermoelectric coupling - a method also found in refrigerators and air conditioners. Thermoelectric coupling uses the combination of heat and cold on two different, but still conductive, surfaces. Connecting the two materials is what creates an electrical current.

Why is this so important?

RTG’s have been using their thermocoupling abilities to power space missions for decades! It’s been a tried and true resource for NASA that has never been the cause of any accident. And out of the three failed missions RTG’s were used on, the resource performed as expected.

This technology has been used in the United States most historical missions, powering explorations to the moon, Mars, Saturn, Pluto and Kuiper Belt. With the help of the Department of Energy, RTG’s will only continue to grow in capabilities and power more missions like that of Mars 2020.

Mars 2020

NASA's Radioisotope Power System the Multi-Mission Radioisotope Thermoelectric Generator will be powering the Mars 2020 space mission set to launch July 2020 and land on Jezero Cater, Mars in February 2021. In preparation for the launch, fueling for the MMRTG began back in July 2019. The fueling process actually begins with the DOE producing plutonium and shipping to a separate lab where it’s broken down and made into pellets. These pellets are then shipped to a long term storage facility for future spacecraft fueling.

Great RTG advancements are on the horizon as we push towards increased space exploration. Interested in replicating your own RTG? Check out Marlow’s Thermoelectric Generator Modules!

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