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Atoms for Space: Nuclear Systems for Space Exploration

Webinar on Atoms for Space

Date and time

15–16 February 2022

View recordings: 15 February → | 16 February →

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The exploration of space requires power at many stages, not only for the initial launch of the space vehicle, but also for various house loads such as instrumentation and controls, communication systems, maintaining the operating environment for the space mission’s essential hardware, etc.

Nuclear can provide long-term electrical power in space. Nuclear systems can be configured in several ways for use in space exploration. These can be broadly classified into following categories:

  • Nuclear power systems: These are the category of power systems that convert heat generated by decay of radioisotopes into electricity or produce power from a reactor, either fission or fusion. They operate continuously over long-duration deep space missions spanning decades without any maintenance and are capable of producing heat and electricity under harsh conditions regardless of sunlight, temperature, charged particle radiation, or surface conditions like thick clouds or dust. There are two types of Radioisotope power systems (i) Radioisotope thermoelectric generators (RTG or RITEG): flight-proven systems that provide power and heat to a spacecraft. These are also referred to as nuclear batteries; and (ii) Radioisotope heater units (RHUs): small devices that provide heat to keep the spacecraft’s electronic instruments and mechanical systems operational in the cold temperatures of the solar system.
  • Nuclear propulsion systems: Propulsion systems that use energy generated from nuclear fission or fusion to provide thrust to a spacecraft are categorized in two broad categories (i) nuclear thermal propulsion (NTP) and (ii) nuclear electric propulsion (NEP) systems. The system works by transferring heat from the reactor to a liquid propellant. That heat converts the liquid into a gas, which expands through a nozzle to provide thrust and propel a spacecraft. In an NEP system, the thermal energy from a nuclear reactor is converted to electrical energy, which is used to drive an ion thruster, eliminating many of the needs and limitations of storing propellants onboard. In addition, a plasma-based propulsion system uses an electric power source to ionize the fuel into plasma. Electric fields heat and accelerate the plasma while the magnetic fields direct the plasma in the proper direction as it is ejected from the engine, creating thrust for the spacecraft. Direct fusion drives use the fusion products for propulsion directly. The fusion products may be mixed with additional plasma to reduce the exhaust velocity and increase the thrust.
  • Surface power systems: These systems are intended to provide extra-terrestrial surface power for extended exploration missions and a possible sustained human presence on other planetary bodies. Fission surface power reactor designs are microreactor that could provide low electrical power in the range of tens of kW for a period spanning one to few decades. The current focus is on using low enriched uranium fuels. Fusion power systems instead would produce power in the range of few hundreds kW to tens of MW.

The two-day webinar will focus on the above-mentioned systems. It will give an overview and historical perspective on the status of development in these areas and showcase the ways in which these systems can be used for space exploration, as well as discuss possible future innovations in the field. Experts of the different systems will present the technologies and applications and answer any question.


Puja Gupta, General Atomics Global Corporation
Chirayu Batra, IAEA
Matteo Barbarino, IAEA

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