meetings - Space Flight Mechanics Committee

Feb 12, 2013 Kauai Salon 3
SESSION 11: TRAJECTORY OPTIMIZATION -- II
Chair: Dr. T.S. Kelso, Center for Space Standards and Innovation
8:00 AAS Simplified Estimation of Trajectory Influence in Preliminary Staging Studies
13-296 Eric Bourgeois, CNES
Staging is a fundamental step for any launcher pre-design process. The total increment of
speed to deliver is a key factor of these studies ; it depends mainly on the characteristics of
the orbit to reach, and also on losses induced by gravity and atmosphere. The estimation of
these losses generally require to perform a trajectory optimization, whom convergence is
not always granted ; the goal of this paper is to present a quick and robust methodology
allowing to estimate losses, with a reasonable accuracy. Description, design and test of this
methodology are presented.
8:20 AAS Indirect Optimization of Low-Thrust Earth Escape Trajectories
13-305 Hao Huang, Beihang University
Indirect optimization is used to compute fuel-optimal earth escape trajectory. Shooting
backward in time converts the unknowns from initial Lagrange multipliers to orbit states at
the final time. Combined with the idea of homotopy method and curve fits technology,
starting from solving two-dimensional short-time fuel-optimal escape trajectory without
control constraint, finally solved the three-dimensional long-time fuel-optimal escape
trajectory with control constraint. This method is validated to be a high-accuracy, goodconvergence
and efficient algorithm for low thrust escape trajectory optimization.
8:40 AAS Developing a tool for the Trajectory Planning of Cubesat missions
13-298 Alexander Ghosh, University of Illinois at Urbana-Champaign; Victoria
Coverstone, University of Illinois at Urbana-Champaign
Developing a modern low thrust trajectory planning tool for applications to picosatellites
poses a number of unique challenges. This work discusses the development of a propellantminimum
trajectory planning tool, which combines a high order integrator, algebraic
differentiation techniques, adaptive step size control, a non-linear programming problem
solver, and analysis of cumulative density functions of the control profile to generate a
robust, extendable solution framework. Discussions of the lessons learned in merging these
techniques, as well as a few demonstrated case studies will be included.
9:00 AAS Automatic Algorithm for Accurate Numerical Gradient Calculation in
13-299 General and Complex Spacecraft Trajectories
Ricardo Restrepo, The University of Texas at Austin; Cesar Ocampo, The
University of Texas at Austin
An automatic algorithm for accurate numerical gradient calculations has been developed.
23 rd AAS / AIAA Space Flight Mechanics Meeting Page 47