Finite-burn Interplanetary Injection from Earth Orbit SNOPT

A MATLAB script for optimizing finite-burn interplanetary injection trajectories (SNOPT version).

PDF document and MATLAB script named escape.m that can be used to analyze a finite-burn maneuver that achieves interplanetary injection from an initial Earth park orbit. The simulation assumes the propulsive maneuver is continuous, coplanar and modeled as a series of optimal discretized steering angles. This script attempts to minimize the scalar magnitude of the finite-burn while solving for user-defined “boundary conditions” or hyperbolic targets.

The orbital motion is modeled using modified equinoctial orbital elements and the script assumes that the thrust magnitude is constant during the entire orbit transfer. Initial guesses for the escape.m script can be determined using the hyper1.m script, “Impulsive Hyperbolic Injection from a Circular Park Orbit”. This MATLAB script provides the park orbit right ascension of the ascending node (RAAN) and the true anomaly of the impulsive injection maneuver on the initial circular park orbit.

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.