re: Returning back from the Moon
Well, I was thinking this way: I'm on the Moon and I want to return back to Earth.
Would it be less energy consuming to ascent directly from the Moon surface into a Trans Earth Injection, rather than reaching Moon orbit and then later, achieving TEI?
Of course, that would indeed mean taking the heat shield and the parachute from the Moon's surface (and ipso facto, to the Moon, earlier).
That might cost too much in terms of energy.
Maybe the best solution would be to travel from the surface to LMO (low moon orbit) with an open vehicle, a bit like this one from Paul Hudson.
Raoul