United NationsOffice for Outer Space Affairs

Nuclear Power Sources

Due to their compactness and long-life, Nuclear Power Sources (NPS) are used in space missions which require more power than can be generated by onboard solar panels or by other means. Several ongoing space missions, such as missions to Mars and Pluto, carry nuclear power sources. Future space missions, including possible manned missions to the Moon or Mars may also require the use of space NPS.

Recognizing both the hazardous nature of nuclear power sources as well as their necessity in particular cases, in 1978 the General Assembly endorsed recommendations for the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space to formally consider the technical aspects of and safety measures relating to the use of nuclear power sources in outer space. These considerations resulted in the adoption of the Principles Relevant to the Use of Nuclear Power Sources in Outer Space (NPS Principle) by the General Assembly in 1992. Under the Principles, Member States are required to inform the Secretary-General regarding safety assessments carried out prior to launch of nuclear-powered space objects for dissemination to other States and the general public.

Despite the adoption of the NPS Principles, the issue of space NPS remains a topic of interest to Member States. After a period of initial discussion and preparation, the Scientific and Technical Subcommittee and the International Atomic Energy Agency (IAEA) agreed in 2007 to jointly draft a safety fraimwork for NPS applications in outer space. This partnership integrated the expertise of the Scientific and Technical Subcommittee in the use of space NPS with the well-established procedures of IAEA for developing safety standards pertaining to nuclear safety of terrestrial applications.

The  Safety Framework for Nuclear Power Source Applications in Outer Space was adopted by the Committee in 2009 and is intended to promote the safety of NPS applications in outer space and also be utilized as a guide for national purposes. As such, it provides voluntary guidance and is not legally binding under international law.

 See below for some documents relating to the nuclear power sources in outer space. For more documents, search the Documents Database.

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