Developing a 5 watt nuclear D cell battery that lasts decades for cubesat space missions

The energy contained in 1 kg of Plutonium-238 is 160,000 times that of chemical sources, i.e. 1.6e06 MJ / kg

This material is from a presentation by Dr. Stephen Howe and the Center for Space Nuclear Research. The authors are Steven D. Howe, Robert C. O’Brien, Troy M. Howe of Center for Space Nuclear Research and Carl Stoots Idaho National Laboratory. It was entitled Compact, Low Specific – Mass Electrical Power Supply for Hostile Environments.

Assuming a 25% conversion efficiency, a Radioisotope Power Source (RPS) would have 400,000 MJ / kg (electric) compared to 0.72 MJ / kg for Li-ion batteries

Option for Low Power Sources for small nanosats and microsats
• Power sources in the 5 – 20 We range entail additional issues and offer additional options
– Requires small quantities of isotope – 62.5 g of Pu-238; 250 g Am- 241 (for 5 We)
– Am-241 is available at around 1 kg/yr commercially
– Am-241 produces 59 kev gammas which are stopped readily by tungsten so the radiation field is very low
– Thus, an Am-241 source could be placed in among the instruments and the waste heat used to heat the platform
– Amounts of isotope are so low that launch approval may be easier, especially with the tungsten encapsulation

The goal is make a 5 watt “D cell” but with nuclear power that lasts decades

SOURCE – Compact, Low Specific – Mass Electrical Power Supply for Hostile Environments by Stephen Howe, et al at Center for Space Nuclear Research

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