Advances in Commercial Space Nuclear Electric Propulsion and Impact on Mission Scenarios
- Paper number
IAC-08.C4.7.-C3.5.5
- Author
Mr. Roger X. Lenard, Sandia National Laboratories, United States
- Year
2008
- Abstract
Typically, nuclear power system designers opt for high operating temperatures because it can be shown from first principles, that if the specific mass of the radiator is high, it is better to have a small one. A small radiator requires high radiating temperatures and optimizes the cycle efficiency at 25 percent, and requires a very high temperature reactor system. The technical effect is to require new fuels, new materials, long test programs and a very high risk/cost project. Ultimately, practical systems require many interacting subsystems that can be combined in ways to produce capabilities either attractive or, on the other hand, undesirable. For example, in the pursuit of perceived reliability, the Jupiter Icy Moons Orbiter concept proliferated its thermal-to-electric power conversion systems. The result was a heavy, expensive, complex system that was less reliable than a system with fewer or even one Brayton system. Herein the author shows that innovative approaches to integrating the essential subsystems can result in a lower weight, hence higher performance system, even though the reactor temperature remains in a tractable range. Since radiator specific mass, and not reactor operating temperature is a very key feature, the author and Allcomp Inc, jointly funded a single-fin carbon-carbon radiator segment. This development enabled a reliable estimate of weight and specific mass from which system operating margins could be generated. We believe that the system will optimize at approximately 7 kg/kWe for a first-generation commercial system. The remainder of the nuclear power system is highly realistic and employs conventional superalloy materials technologies. From these developments, the author addresses differences between the JIMO development and the IOSTAR® nuclear tug, and implications on a few mission scenarios.
- Abstract document
- Manuscript document
IAC-08.C4.7.-C3.5.5.pdf (🔒 authorized access only).
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