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This HP PPL program demonstrates how to model the trajectory of an aerospace vehicle in the flight path coordinate system. This example flies an STS maximum cross range re-entry trajectory using angle-of-attack and bank angle information extracted from a trajectory optimization program.

The initial flight path coordinates can be defined by the user according to the following example. Please note the units of each input.

// --------------------------------------
// define initial flight path coordinates
// --------------------------------------

// altitude (kilometers)

xalt := 121.92;

// relative velocity (kilometers/second)

vrel := 7.80288;

// geographic declination (degrees)

dec := 0.0;

// geographic longitude (degrees)

elon := 0.0;

// azimuth (degrees)

azim := 90.0;

// flight path angle (degrees)

fpa := -2.39780555815067;

The final simulation time, in seconds, can be set by the user in line 180 of the source code.

// final simulation time (seconds)

tf := 1000.0;

The software and documentation for this program can be downloaded at

https://www.dropbox.com/s/nj4kpk4kowlqj6...s.zip?dl=0