Optimization of perigee burns for manned interplanetary missions

摘要

In choosing an engine concept for the rocket vehicle to be used for the initial manned exploration of Mars, the two main factors in the decision should be what can be feasibly built and flight qualified within approximately the next 20 years, and what level of engine performance is required to safely perform these missions. In order to reduce the overall cost in developing this next generation space transportation system, it would be desirable to have a single engine design that could be used for a broad class of missions (for example, cargo and piloted lunar and Mars missions, orbit transfers around the Earth, and robotic missions to the planets). The engine thrust that is needed for manned Mars missions is addressed in this paper. We find that these missions are best served by a thrust level around 75,000 lbf to 100,000 lbf, and a thrust-to-engine weight ratio of about three. This thrust level might best be obtained by clustering five 15,000 lbf or 20,000 lbf engines. It may be better to throttle the engines back from full power between perigee burns, rather than shutting down. 5 refs., 4 figs.