In this paper an optimal new reentry guidance method is proposed. This method is based on online trajectory
optimization that optimal guidance commands derived from optimal problem solutions. For rapid and online solution of
optimal control problem, we present a method which is a combination of differential flatness concept, B-spline curves,
direct collocation and nonlinear programming. With closed loop trajectory optimization and implementation of receding
horizon control concept, open loop optimal control solutions are related to current vehicle and target conditions. In this
case guidance commands are generated based on desired functional and various constraints. For proofing of capabilities
of this guidance method, an example of reentry guidance is discussed with wind and model uncertainties.