Physics of Nuclear Propulsion – An Introduction
- Paper number
IAC-05-C3.5-C4.7.02
- Author
Prof. Claudio Bruno, University of Rome "La Sapienza", Italy
- Year
2005
- Abstract
With renewed interest in nuclear propulsion due to the JIMO missions and the Space Exploration Initiative in the US, there is also a need for propulsion engineers to revisit the basic physics associated to nuclear propulsion. Accordingly, starting from the description of the fundamental three forces, the corresponding sources of energy, from gravitational to nuclear, are discussed and their energy density ranked, showing that nuclear propulsion is the only practical alternative to chemical for fast, deep space and interplanetary exploration. Depending on specific missions, the nuclear engines mass consumption (specific impulse) may be modulated, and their thermal material issues may be resolved by addition of inert mass (propellant) to the products of nuclear reactions. Generally, relativistic effects must be accounted for in calculating performance of nuclear propulsion systems: depending on mode of utilizing their nuclear energy source, they may produce jet exhaust speeds non-negligibly small with respect to the speed of light. Choice between direct thrust generation, as in nuclear thermal propulsion, or indirect, as in nuclear-electric propulsion, are discussed, and examples of past experience with NTR in the US and the former Soviet Union are reported, indicating this propulsion technology is viable as it is. Finally, nuclear so-called ‘massless’ propulsion based on photonics is also illustrated, showing that it too has specific impulse limitations, due to the relativistic mass conversion into energy.
- Abstract document
- Manuscript document
IAC-05-C3.5-C4.7.02.pdf (🔒 authorized access only).
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