Optimal Design For Mars Probe In Near-Center Braking And Orbit Keeping

With the arrival of the upsurge of Mars Exploration in the new century, it is going to become hot topic that Mars probe brakes near the Mars and keeps its orbit in a long time. In this paper, with"Deep space probe autonomous orbit control optimization"as the background, we discussed the problems of braking near the Mars and orbit keeping for Mars probe. There were two innovations which are, firstly, using the virtual satellite method in near Mars braking and secondly, deriving low-thrust orbit keeping algorism.In the paper, according to the needs of different tasks, appropriate coordinate systems were established and a dynamic model considering various perturbation factors was given. The perturbation includes Mars Non-spherical gravitational perturbation, sun and earth gravitational perturbation. The high accuracy dynamic model will be used in the orbital integral.This paper analyzed the near Mars braking problem and derived, respectively, fixed-thrust and optimal-thrust braking algorism both of which could accomplish the near Mars braking mission well, however, the results were different in accuracy. The virtual satellite method was used in optimal-thrust algorism. It's proved that this method could be used in the transfer between hyperbolic orbit and elliptical one.In the paper, according to the high accuracy dynamic model, it was analyzed that the orbit elements of the Mars probe would change in the long term. A low-thrust orbit keeping algorism was derived. From the result we could see that this algorism would lower the fuel expend and the number of starting engine.The results obtained in this dissertation can provide theoretic reference to the further research.