Sensitivity analysis for rapid prototyping of entry vehicles

A procedure is presented for the application of parameter value-function analysis to the problem of rapid prototyping of entry vehicles. The trajectory optimization problem is imbedded in a family of canonically parameterized optimal control problems. Rather than repeatedly solving an ensemble of trajectory optimization problems, it is shown that a combination of sensitivity- and covector mapping theorems can be easily exploited to gauge quickly the effect of a parameter on the performance of the entry vehicle. Although the theory is not limited to the type or number of parameters, the ideas are demonstrated with three design variables: the maximum heating rate on the vehicle, the parasitic drag coefficient, and the vehicle mass. No change in the proposed method is necessary to carry out a similar analysis for other plant parameters for additional purposes such as the design of robust guidance algorithms. With use of the Legendre pseudospectral method and results from nonsmooth analysis, it is shown how to validate the sensitivity results.