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Initial feasibility studies suggest that the utility of certain storable rocket propellants can be extended to include life support and other essential services in the space environment, thereby improving the habitability and over-all performance of manned systems. Two liquid combinations are considered: hydrazine/hydrogen peroxide and hydrazine/nitrogen tetroxide. Both are good propellants, and their oxidizer-rich combustion in a gas generator theoretically yields potable water, a two-gas atmosphere of controllable composition, and energy for power generation and/or thermal management. The basic thermochemical relationships are presented from which performance in specific areas is derived. Problems of contamination , safety, and reliability are discussed, and possible applications to manned probes, space stations, extravehicular operations, planetary bases, biosatellites, and high-altitude aircraft are explored. The concept is applied in some detail to two hypothetical missions, and its over-all effectiveness is compared with that of more conventional approaches.

Comprehensive overviews of energy storage technologies for solar applications are already available [1,2,3,4,5,6]. Collectively they characterize the better known concepts and materials much more thoroughly than would be possible here. I shall not try to duplicate those efforts. However, the existing overviews do not include some potentially promising technical approaches, that at the time of compilation were relatively immature or had not yet appeared prominently in the literature. Other developments, of course, have emerged in the intervening years. What is needed most right now is an update with new perspectives, concentrating on a manageable number of new and exciting developments. To this end I seize the present opportunity.

The term thermal energy storage can apply to any storage function for which the principal inputs and outputs are thermal energy, whether as “hotness” or as “coolness”. Generally, hotness storage technologies have received more research and development support because they have more uses and cover a wider range of temperatures, but for building applications the storage of coolness (commonly called cool storage) has acquired at least equal prominence in regions where comfort cooling is a major use of energy.

Thermal energy storage (TES) is the term usually applied to any storage function for which the principal inputs and outputs are thermal energy. In building applications it may be “hotness” storage for space heating or domestic water heating, “coolness” storage for air conditioning, or storage at room temperature for stabilization within the comfort zone. It can substantially improve the economics of conventional space conditioning, and in solar applications it is virtually indispensible.

Direct solar radiation is shown to be a potentially superior source of energy for the thermochemical production of hydrogen from water, especially in a regionally self-sufficient hydrogen economy. Its impact on chemical cycle selection, conversion efficiency, operating mode, plant siting, plant capacity, and product cost is compared with that of a nuclear heat source. Conceptual designs and development goals are suggested.