Optimal Aeroassisted Coplanar Orbital Transfer Using an Energy Model

Download or read book Optimal Aeroassisted Coplanar Orbital Transfer Using an Energy Model written by National Aeronaut Administration (Nasa) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric portion of the trajectories for the aeroassisted coplanar orbit transfer was investigated. The equations of motion for the problem are expressed using reduced order model and total vehicle energy, kinetic plus potential, as the independent variable rather than time. The order reduction is achieved analytically without an approximation of the vehicle dynamics. In this model, the problem of coplanar orbit transfer is seen as one in which a given amount of energy must be transferred from the vehicle to the atmosphere during the trajectory without overheating the vehicle. An optimal control problem is posed where a linear combination of the integrated square of the heating rate and the vehicle drag is the cost function to be minimized. The necessary conditions for optimality are obtained. These result in a 4th order two-point-boundary-value problem. A parametric study of the optimal guidance trajectory in which the proportion of the heating rate term versus the drag varies is made. Simulations of the guidance trajectories are presented. Halyo, Nesim and Taylor, Deborah B. Unspecified Center...