Summary of Closed Brayton Cycle Development Activities at NASA

by L. Mason
NASA Glenn Research Center

Complete Paper to be Available Following the 2011 Supercritical CO2 Power Cycle Symposium

NASA has been involved in the development of Closed Brayton Cycle (CBC) power conversion technology since the 1960s. CBC systems can be coupled to reactor, isotope, or solar heat sources and offer the potential for high efficiency, long life, and scalability to high power. In the 1960s and 1970s, NASA and industry developed the 10 kW Brayton Rotating Unit (BRU) and the 2 kW mini-BRU demonstrating technical feasibility and performance. In the 1980s, a 25 kW CBC Solar Dynamic (SD) power system option was developed for Space Station Freedom and the technology was demonstrated in the 1990s as part of the 2 kW SD Ground Test Demonstration (GTD). Since the early 2000s, NASA has been pursuing CBC technology for space reactor applications. Before it was cancelled, the Jupiter Icy Moons Orbiter (JIMO) mission was considering a 100 kWclass CBC system coupled to a gas-cooled fission reactor. Currently, CBC technology is being explored for Fission Surface Power (FSP) systems to provide base power on the moon and Mars. These recent activities have resulted in several CBC-related technology development projects including a 50 kW Alternator Test Unit, a 20 kW Dual Brayton Test Loop, a 2 kW Direct Drive Gas Brayton Test Loop, and a 12 kW FSP Power Conversion Unit design.