Nuclear Power in Space Missions

Syllabus: GS3/ Science and Technology

Context

• The US recently announced plans under its Lunar Fission Surface Power Project to deploy a small nuclear reactor on the moon by the early 2030s.

Why Is Nuclear Power in Space Gaining Importance?

• The Moon has little atmosphere and experiences 14-day stretches of darkness, this makes solar energy unreliable in some of the most critical regions.
• A small lunar reactor could operate continuously for a decade or more, powering habitats, rovers, 3D printers and life-support systems. 
• Developing this capability is essential for missions to Mars, where solar power is even more constrained.

Evolution in Nuclear Power in Space

• Radioisotope Thermoelectric Generators (RTGs): It converts heat released by the slow decay of plutonium-238 nuclei into electricity, and is immune to dust and darkness. They are used in spacecraft like Voyager, Cassini, and Curiosity.
  • However, they produce only hundreds of watts, insufficient for human habitats or industry.
• Compact Fission Reactors: They are capable of generating tens to hundreds of kilowatts.
• Nuclear Thermal Propulsion (NTP): Heats hydrogen using a reactor and expels it to generate thrust.
  • The DRACO programme in the USA will test this technology in lunar orbit by 2026. It could shorten Mars travel times significantly, reducing astronauts’ radiation exposure.
• In nuclear electric propulsion, reactor-generated electricity ionises a propellant, offering years of efficient thrust for deep-space probes and cargo missions.

International Legal Framework 

• Outer Space Treaty (1967): 
  • Permissible: It permits peaceful purposes on the Moon and other celestial bodies and bans nuclear weapons/WMD anywhere in space or on celestial bodies.
  • Article IX: States must act with due regard to interests of others, hence, no territorial claims can be made.
• Liability Convention (1972): Launching State is absolutely liable for damage on Earth/aircraft; fault-based liability for damage in space/on the Moon. It also provides claims/settlement machinery.
• Moon Agreement (1979) (few parties; not widely accepted): It adds environmental and rescue duties on the Moon; recognizes the Moon’s resources as the “common heritage”. Applies only to its Parties.
• 1992 UN Principles: Non-binding resolution recognising the role of nuclear power in missions where solar is insufficient; lays down safety, transparency, and consultation guidelines.
• India is a signatory to the outer space treaty, but not to the Moon Agreement. India is also a signatory to the Artemis Accords (2023) in which parties commit to transparency, safety zones and data sharing.

Concerns

• There is a lack of legally binding global rules for nuclear waste disposal on the Moon.
  • The Outer Space Treaty forbids countries from placing weapons of mass destruction in earth orbit, it’s silent on nuclear propulsion for peaceful purposes. 
  • The Liability Convention isn’t clear about accidents involving nuclear reactors in cis-lunar space or beyond.
• Risk of radioactive contamination if accidents occur during launch or lunar operations, could disrupt pristine environments.
• As space becomes a theatre of strategic competition, Compact reactors have dual-use potential, raising militarisation concerns.
• Safety zones around reactors might be interpreted as territorial claims, violating the non-appropriation principle.

Way Ahead

• The UN’s 1992 Principles should be updated to explicitly include propulsion reactors, establish safety benchmarks, and define end-of-life disposal standards. 
• The UN Committee on the Peaceful Uses of Outer Space needs to adopt binding environmental protocols to govern safe launches, preventing contamination, and disposing of nuclear systems. 
• A multilateral oversight mechanism modelled on the International Atomic Energy Agency could certify designs, verify compliance, and enhance transparency.

Source: TH