Review of Spacecraft Entry Guidance.

The entry vehicle researched in this paper is a low lift-to-drag ratio spacecraft. Its lift-to-drag ratio is smaller than 0.5. Based on the survey of atmospheric entry guidance techniques for low lift-to-drag ratio spacecraft, firstly the required constraint conditions and the challenges encountered in the earth and Mars atmospheric entry guidance process are analyzed. Then the algorithms for atmospheric entry guidance are summarized. Simultaneously the merits and drawbacks of the different guidance algorithms are compared and analyzed. Finally, the difficulties and future research directions of entry guidance techniques are forecasted. [ABSTRACT FROM AUTHOR]