= Orbit Questions =

I've been pondering makeup momentum to a construction orbit station delivered from the Moon, and I got stuck thinking about orbital inclinations.

The Moon has a lot of tasty angular momentum, and lunar ice may be good for shielding, ... BUT ...

A proper Arnold/Kinsbury spaceport capture system is coplanar with the spaceport orbit.  Since a near equatorial Earth orbit is inlined 23 degrees to the ecliptic, and lunar orbital inclination is 5 degrees from the ecliptic and precesses around it every 6800 sidereal days, launching mass from a fixed launcher on the Moon, and delivering it coplanar and collinear near construction orbit apogee, AND threading down a decellerator tube ... all the requirements add up to a "not oughta work".

I still need to learn about non-coplanar tidal effects on highly eccentric orbits.  Stationkeeping against tidal forces for GEO comsats requires about 50 m/s of thrust per year, and my hunch is that a highly eccentric orbit will be more sensitive than a circular orbit.

Can someone suggest an open-source 3D "orbital CAD" program useful for such problems?  Kepler orbit pairs transformed into three dimension make my brain hurt, never-mind patched conics, tidal perturbations, and oblateness-driven apsidal precession.