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A new ultrathin-backed semipermeable membrane has been developed which shows considerable promise as a gas separator for engine bleed air to provide nitrogen-rich air for aircraft fuel tank inerting. The membrane is a silicone, polycarbonate copolymer of 1500 Å effective thickness, deposited on a reinforced porous backing. The selective removal of oxygen provides oxygen concentrations of less than 9% in the inerting gas. Small-scale testing demonstrated that the backed membranes are suitable in the aircraft environment. A system using such membranes avoids the logistic and service requirements of tanked liquid nitrogen.

As part of the SP-100 Space Reactor Power System Program being undertaken for the U. S. Department of Energy, GE is developing a thermoelectric (T/E) power converter which utilizes reactor delivered heat and transforms it into usable electric power by purely static means. This converter is based to GE's product line of successful thermoelectric space power systems. The SP-100 power converter embodies the next generation improvement over the type of T/E converter successfully flown on the six U. S. space missions. That is, conduction coupling of T/E cell to both the heat source and the heat rejection elements. The current technology utilizes radiation coupling in these areas. The conduction coupling technique offers significant improvements in system specific power since it avoids the losses associated with parasitic ΔT's across the radiation gap between the heat source and the hot junction of the thermoelectric (T/E) cell.

The SP-100 Space Reactor Power System is being developed by GE, under contract to the U.S. Department of Energy, to provide electrical power in the range of 10's to 100's of kW. The system represents an enabling technology for a wide variety of earth orbital and interplanetary science missions, nuclear electric propulsion (NEP) stages, and lunar/Mars surface power for the Space Exploration Initiative (SEI). An effective infrastructure of Industry, National Laboratories and Government agencies has made substantial progress since the 1988 System Design Review. Hardware development and testing has progressed to the point of resolving all key technical feasibility issues. The technology and design is now at a state of readiness to support the definition of early flight demonstration missions. Of particular importance is that SP-100 meets the demanding U.S. safety, performance, reliability and life requirements.

This paper describes how the SP-100 Space Reactor Power System (SRPS) can be tailored to meet the specific requirements for a lunar surface power system to meet the needs of the consolidation and utilization phases outlined in the 90-day NASA SEI study report. This same basic power system can also be configured to obtain the low specific masses needed to enable robotic interplanetary science missions employing Nuclear Electric Propulsion (NEP). In both cases it is shown that the SP-100 SRPS can meet the specific requirements. For interplanetary NEP missions, performance upgrades currently being developed in the area of light weight radiators and improved thermoelectric material are assumed to be technology ready in the year 2000 time frame. For lunar applications, some system rearrangement and enclosure of critical components are necessary modifications to the present baseline design.