PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semimajor axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory.
The patched conic approximation
divides the planetary mission into three
parts: (1) the departure phase, in which
the two relevant bodies are Earth and the
spacecraft, and where the trajectory is a
departure hyperbola with Earth at the
focus; (2) the cruise phase, in which the
two bodies are the Sun and the spacecraft,
and where the trajectory is a transfer
ellipse with the Sun at the focus; and (3)
the arrival phase, in which the two bodies
are the target planet and the spacecraft,
where the trajectory is an arrival hyperbola
with the planet as the focus.
This work was done by Brooke Anderson Park and Henry Wright of Langley Research Center. LAR-17446-1