Abstract: This paper firstly classifies the nonlinear control approaches into three categories: the approaches based on Lyapunov function selection, the approaches based on optimal control schemes, and the approaches based on linear approximation and domination, and gives a brief overview on each category. Along with this classification, an overview on the nonlinear flight control approaches is also provided, and the concept of quasi-linear systems is then introduced. Finally, the second-order quasi-linear system descriptions of six typical control problems arising from the fields of satellite attitude and orbit control as well as vehicle guidance and control are provided.

Key words: Flight vehicle control, Quasi-linear systems, Attitude control, Orbit control, Space rendezvous and interception