Finite-burn lower of a circular or elliptical orbit - SNOPT

This script can be used to model a finite-burn maneuver that lowers the perigee or apogee of an initial circular or elliptical orbit.

This script can be used to optimize a single finite-burn orbital maneuver that lowers the perigee or apogee of an initial circular or elliptical orbit. The simulation assumes the propulsive maneuver is continuous, co-planar and modeled as a series of optimal discretized steering angles. The script attempts to minimize the thrust duration of the finite-burn while solving for user-defined orbital boundary conditions at burnout such as perigee and/or apogee altitudes.

In this MATLAB script, the Keplerian orbital motion is modeled using modified equinoctial orbital elements and the scripts assume the thrust magnitude and specific impulse are constant during the entire orbit transfer maneuver. Information about modeling in this flight path system can be found in Appendix A, Trajectory Modeling and Targeting in the Modified Equinoctial Orbital Elements System of the included PDF user's manual.

The optimization of the maneuver steering angles is performed using the SNOPT nonlinear programming (NLP) algorithm. MATLAB versions of SNOPT for several computer platforms can be requested/purchased at Professor Philip Gill’s web site which is located at http://scicomp.ucsd.edu/~peg/. Professor Gill’s web site also includes a PDF version of the SNOPT software user’s guide and other technical reports.