Abstract
A system that integrates on hydrogen-base all of energy on propulsion and power needed in a space transportation system is one of mechanisms for operating reusable space transportation system frequently. In this paper, the concept design for the integrated system is presented to discuss the effectiveness of the system. As evaluation functions, (1) weight, (2) cost, and (3) turn-around time (operability) are considered. Modeling of the energy system is conducted focusing energy flow and connections between elements that configure the energy system. Assuming a space transportation mission and regarding the required energy function in the mission as boundary conditions, conceptual designs of the integrated energy system using the developed model are performed. There is a trade-off relationship between the three evaluation functions. For weight reduction, integration of fuel species and the scale of the energy storing elements, those are an accumulator and a battery, is effective. For reduction of the turn-around time, toxic fuels have to be removed. An adoption of batteries reduces the number of connections between the elements so that it contributes to improvement in operability. As for cost, the part related to the manufacturing depends on weight and that related to the operation does on the turn-around time in the present cost model. Hydrogen and oxygen-based integrated energy system, although additional elements are to be necessary and a disadvantage in terms of weight is caused, is effective in reducing the operating costs and the turn-around time in case that a large amount of high frequency transport is desired because it is possible to improve the operability significantly.
