Preliminary design considerations of a high performance Hall-currentaccelerator.

Abstract

Details of the analysis for predicting space storability are presented in Ref. 2. Briefly, the major source of deviations between experimental results and predicted results is examined recognizing the fact that the analytical and experimental results tend to converge as the tank size increases. Results can then be extrapolated to cryogenic propellants other than LN2. Typical results of this analysis are shown in Fig. 7. Losses of propellants other than hydrogen are acceptable for the tank sizes shown. The long-term storage of hydrogen becomes practical with tank diameters >15 ft. This work has shown that heat leaks to cryogenic tanks are due mainly to penetrations of the insulation of supports and propellant lines to the erigine(s). Only 27% of the heat flow to the 8-ft spherical tank occurs directly through the insulation. A significant development effort to reduce heat leakage through penetrations is needed. The development of a re tractable support system bears strong consideration. The effects of a zero-gravity environment on venting and on heat-transfer coefficients, and the heat input from the pressurization system gas, were not considered because of program limitations. These areas are currently being investigated bv the AFRPL. The effect of the ground launch environment on the performance of the superinsulation of a hydrogen tank is currently being investigated by NASA and will affect the results presented for hydrogen storability.