Trans-Lunar Trajectory Optimization – SNOPT

SNOPT version of the tlto_matlab script used to design preliminary lunar missions from Earth park orbit to B-plane encounter.

This submission is a MATLAB script named tlto_matlab_snopt that can be used to design preliminary lunar missions from Earth park orbit to B-plane encounter at the moon. The software assumes trans-lunar injection (TLI) occurs impulsively from a circular Earth park orbit. The B-plane coordinates used for targeting the final conditions at the moon are expressed in a moon-centered (selenocentric) mean equator and IAU node of epoch coordinate system. The results from this scientific simulation can be used as an initial guess for a finite-burn trajectory optimization program.

This MATLAB script reads JPL DE430 lunar and solar ephemerides in a machine-independent binary format (kernels) which are available from the SPICE web site and by anonymous ftp from ftp://ssd.jpl.nasa.gov/pub/eph/planets/bsp. These *.bsp ephemeris files are IEEE-Little Endian style of binary kernel. This is the binary form native to PC/Linux, PC/Windows and MAC/Intel machines. Additional information about JPL ephemerides can be found at http://naif.jpl.nasa.gov/naif/.

The tlto_matlab_snopt script uses routines from the MICE software suite to read and evaluate the JPL ephemeris file. Platform-specific MICE mex files, support functions and the binary ephemeris file (de430.bsp) are available at naif.jpl.nasa.gov/naif/toolkit_MATLAB.html. MICE is a MATLAB implementation of the SPICE library created by JPL.

MATLAB versions of SNOPT for several computer platforms can be purchase/requested 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.