NASA looks to a nuclear future

by Chris Bergin

NASA has initiated a study into the use of nuclear power in the space program. Planning is underway for the next phase of space exploration and current propulsion methods are reaching the bounds of their capabilities due to President Bush’s ‘Vision of Space Exploration’.

The US Administration has tasked NASA with a mandate of achieving human space travel to Mars – as well as returning to the Moon – in the 2020’s, this will require more powerful forms of propulsion.
Project Prometheus will research and develop nuclear fission reactors for use during future space missions. The agency believes that a reactor the size of a domestic refrigerator would be able to provide energy for propulsion and electrical systems during missions far longer than currently undertaken.

Power consumption is one of the major constraints for current space missions, for example the Spirit and Opportunity rovers currently operating on Mars have a maximum of 140 watts of power available to them. NASA estimates that a nuclear reactor would be able to supply in the order of thousands of kilowatts thus revolutionising the capabilities of future missions, allowing more sophisticated scientific instruments to be included and high data rate transmission back to Earth. The available energy could also be harnessed for propulsion, opening a range of possibilities for missions lasting for several years and visiting multiple planets.
The study has been undertaken in conjunction with the Department of Energy (DOE), the body responsible for regulating and researching both civilian and military nuclear capabilities in the USA.
As the project develops it is likely that new facilities will be required to handle the nuclear components through prototype, production and launch. Current plans for the technology involve improving the performance of future robotic probes on extended deep space missions, possibly expanding into human space-flight.  The Kennedy Space Centre has been identified as a likely launch site for future nuclear missions.

However, the use of nuclear power in space raises environmental questions. Some early feasibility and conceptual studies identified a potential need for new facilities such as a land-based prototype reactor to test the reactor design before actual use, and launch site support facilities for final assembly and testing of the spacecraft before launch. Such questions would not be done before considering the environmental impacts including preparation of the appropriate site-specific National Environmental Policy Act of 1969 documentation.

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