Porkchop plot

Representative porkchop plot for the 2005 Mars launch opportunity (horizontal axis: departure dates in mm/dd notation, vertical axis: arrival dates (mm/dd))

A given blue contour represents a solution with a constant C3.

The center of the porkchop is the optimal solution for the lowest C3.

The red lines represent trips with the same travel time for the trajectory.

The green lines represent the Sun-Earth-Probe angle upon departure.[clarification needed]

In orbital mechanics, a porkchop plot (also pork-chop plot) is a chart that shows level curves of equal characteristic energy (C3) against combinations of launch date and arrival date for a particular interplanetary flight.[1] The chart shows the characteristic energy ranges in zones around the local minima, which resembles the shape of a porkchop slice.

By examining the results of the porkchop plot, engineers can determine when a launch opportunity exists (a 'launch window') that is compatible with the capabilities of a particular spacecraft.[2] A given contour, called a porkchop curve, represents constant C3, and the center of the porkchop the optimal minimum C3. The orbital elements of the solution, where the fixed values are the departure date, the arrival date, and the length of the flight, were first solved mathematically in 1761 by Johann Heinrich Lambert, and the equation is generally known as Lambert's problem (or theorem).[1]

  1. ^ a b Goldman, Elliot. "Launch Window Optimization: The 2005 Mars Reconnaissance Orbiter (MRO) Mission". Colorado Center for Astrodynamics Research. Archived from the original on 2017-04-13. Retrieved 2007-12-30.
  2. ^ "'Porkchop' is the First Menu Item on a Trip to Mars". NASA. Accessed December 30, 2007.