Pork Chop Plots of Ballistic Earth-to-Mars Trajectories

A MATLAB Script for Creating Pork Chop Plots of Ballistic Earth-to-Mars Trajectories

This submission is a MATLAB script called e2m_porkchop that can be used to create and plot interplanetary “pork chop” plots for Type I and Type II Earth-to-Mars ballistic trajectories. These contour plots illustrate the behavior of departure energy (C3L), right ascension (RLA) and declination (DLA) of the departure maneuver, time-of-flight, and arrival v-infinity, DLA and RLA, and total heliocentric scalar delta-v for a range of user-defined departure and arrival calendar dates.

The data required for these contour plots is created by solving the heliocentric, two-body “patched-conic” Lambert problem. A patched-conic trajectory ignores the gravitational effect of both the departure and arrivals planets on the heliocentric trajectory. Type I trajectories are characterized by heliocentric Earth-to-Mars transfer angles which are less than 180 degrees while Type II trajectories have transfer angles greater than 180 degrees. Pork chop plots are typically used for preliminary mission analysis because they provide an estimate of the minimum energy trajectory and other important performance characteristics.

The angular coordinates of the departure and arrival heliocentric delta-v are provided in the Earth mean equator and equinox of J2000 (EME2000) coordinate system. The total delta-v is the sum of the heliocentric departure and arrival scalar delta-v values. The e2m_porkchop script can be easily modified for other departure and arrival planets.

This MATLAB script reads a JPL planetary ephemerides in a machine-independent binary format (kernels) which are available from the JPL SPICE web site. 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. Ephemeris and other required data files, platform dependent versions of the MICE mex file and other functions are available at naif.jpl.nasa.gov/naif/toolkit_MATLAB.html