The application of SP-100 technology in a lunar surface power system

Abstract

This paper describes a conceptual design study addressing the application of SP-100 Space Reactor Power System technology to a Lunar Surface Power System (LSPS). SP-100 technology is readily adaptable to the unique environment of the lunar surface and can be used to meet lunar outpost load demand. Key functional, design and interface requirements are defined for the lunar outpost application. Special safety considerations are outlined that result from the presence of astronauts in the vicinity of an operating LSPS. A conceptual design is presented for a 100 kW, LSPS that builds on the technology and design for the orbital SP-100 Generic Flight System (GFS). The Power Assembly of the LSPS is essentially the same as the GFS, while the total system is repackaged for installation on the lunar surface, heat rejection from the lunar surface, and power transmission to the lunar outpost. The LSPS interfaces with the Shuttle C as the launch vehicle and with NASA's proposed Lunar Transfer Vehicle/Lunar Excursion Vehicle (LTV/LEV) for lunar orbit rendezvous and decent. Transportation of the LSPS once on the lunar surface is accomplished using NASA's proposed Lunar Excursion Vehicle Payload Unloader (LEVPU). Each LSPS unit is emplaced on the lunar surface in a pre-drilled cavity. An overall power system architecture is described that relies on the sequential emplacement of four, 50 kW, thermoelectric LSPS units and two, 375 kW, Stirling LSPS units (or three 188 kW, HYTEC units) to meet lunar outpost load demand and availability requirements while maximizing flexibility and minimizing overall system mass. The optimum deployment scheme for the LSPS units to meet lunar outpost load is outlined. This paper examines the use of SP-100 technology to meet the load demands of the lunar outpost outlined in Reference 1. It defines the functional, design, operational, and environmental requirements associated with a Lunar Surface Power System (LSPS), outlines the conceptual design of the LSPS, and describes a power system architecture that meets these requirements by emplacement of multiple LSPS units. The load demand associated with NASA's Option 5A is used as the reference mission scenario for this study. After reviewing the five reference mission approaches presented in Reference 1, Option 5A was selected as the most probable load demand profile. This load demand profile is illustrated in Figure 1 . In areas where this loaddemand profile is important to system conceptual design, sensitivity studies were conducted to determine the impact of different load profiles. Although the power system architecture presented below is for a specific load demand, key results are generally applicable to any load demand. The areas where the results are not generally applicable are indicated as such.