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This HP Program calculates the single impulsive deorbit maneuver required to establish a reentry altitude and flight path angle relative to a non-rotating, spherical Earth. The algorithm uses a tangential delta-v applied opposite to the velocity vector of an initial elliptical orbit to establish the de-orbit trajectory.

The following is a "hard-wired" example with the program input in bold font.

// perigee altitude (kilometers)

hp := 285.798;

// perigee radius (kilometers)

rp := req + hp;

// apogee altitude (kilometers)

ha := 35785.922;

// apogee radius (kilometers)

ra := req + ha;

// entry altitude (kilometers)

hentry := 111.252;

// entry flight path angle (degrees)

fpae := -4.0;

The software will compute and display the orbital elements of the deorbit trajectory and the magnitude of the required deorbit delta-v.

The zipped archive for the software and documentation for this example can be downloaded from

https://www.dropbox.com/s/2f2zxm1frqxycp...t.zip?dl=0