NAME: moid PURPOSE: (one line only) Compute the minimum orbit intersection distance between two orbits DESCRIPTION: CATEGORY: Celestial Mechanics CALLING SEQUENCE: distance = moid(orb1,orb2) INPUTS: orb1 - Anonymous structure containing the first orbit. The following tags must be defined in the structure: semi - semi-major axis in AU ecc - orbital eccentricity inc - orbital inclination (radians) node - Longitude of the ascending node (radians) arg - Argument of perihelion (radians) manom - mean anomoly (radians) jdepoch - Julian Date of the epoch of the orbit orb2 - Structure with the second orbit (same tags as the first orbit) OPTIONAL INPUT PARAMETERS: KEYWORD INPUT PARAMETERS: OUTPUTS: return value - the minimum orbital intersection distance between the two orbits, in AU. KEYWORD OUTPUT PARAMETERS: COMMON BLOCKS: mwb_moid - for internal use only SIDE EFFECTS: RESTRICTIONS: PROCEDURE: MODIFICATION HISTORY: Written by Marc W. Buie, Southwest Research Institute, 2014/01/09