A trajectory generation framework for modeling spacecraft entry in MDAO

• This paper presented a novel trajectory generation algorithm for a hybrid analytical, numerical formulation.
• It was found that the traditional Shuttle Entry Guidance drag based approach has significant issues with segmentation discontinuities and sensitivity to atmospheric non-linearities. Thus, an analytical representation of the reference bank profile was developed to eliminate the above.
• The adaptability of the Trajectory Generation Framework relies on automating the selection of transition events using deterministic approaches.It was demonstrated that quantitative values of range error, heat load, and bank rate can be used to select the best reference trajectory.

In this paper a novel trajectory generation framework was developed that optimizes trajectory event conditions for use in a Generalized Entry Guidance algorithm. The framework was developed to be adaptable via the use of high fidelity equations of motion and drag based analytical bank profiles. Within this framework, a novel technique was implemented that resolved the sensitivity of the bank profile to atmospheric non-linearities. The framework׳s adaptability was established by running two different entry bank conditions. Each case yielded a reference trajectory and set of transition event conditions that are flight feasible and implementable in a Generalized Entry Guidance algorithm.