Comparison of evolving photovoltaic and nuclear power systems for earth orbital applications

As the Space Shuttle becomes fully operational, NASA and DOD missions may require high power Earth orbital power systems. Total end-to-end comparisons are made for representative photovoltaic and nuclear systems. The photovoltaic systems examined range from flight demonstrated conventional solid substrate solar array/NiCd battery approaches to undemonstrated advanced array/energy storage systems. End-of-life power to mass performance is presented for 25 kW photovoltaic arrays at orbital altitudes ranging from low Earth orbit to geosynchronous orbit for 1, 5, and 10 year missions. The SP-100 nuclear power system is examined for three technology levels ranging from near term to advanced approaches for 25 and 100 kWe power levels. The system specific power, or ratio of load power to power system mass, for each end-to-end photovoltaic and nuclear system is presented. Detailed descriptions of various photovoltaic and nuclear power systems together with their associated electrical block diagrams are also presented.