This is fine.  Kepler's equation is going to converge for the reasonable orbits of the Earth-moon barycenter and the Moon.  At least it better!  Since we'll probably never do it, let's change this TODO to just a regular explanation comment: "STK Components uses a numerical method to find the eccentric anomaly in the case that Kepler's equation does not converge.  We don't expect that to ever be necessary for the reasonable orbits used here."  We try to avoid TODOs in master (though there are some), instead preferring GitHub issues for thing we might actually do, and comments of explanation for things we probably won't.