I've been watching some recorded videos from the April 22 - 24, 2014 Humans2Mars conference (videos and live streams, when available, are on the National Institute of Aerospace channel on Livestream), in particular the Mike Raftery's (Boeing; Director, ISS Utilization and Exploration) presentation on a concept manned mission to Mars that was prepared by Boeing and Energia, starting roughly 15 minutes into this video. This slide caught my attention:
As you can see, two mission stages call for an orbital assembly at Earth-Moon L2 Lagrange point (EML2), but all the component parts are supposed to spiral to EML2 beforehand.
Now, we know (with some trial and error, failed rendezvous attempt of Gemini 4 with spent Titan II launch vehicle's upper stage, and then first successful rendezvous of Gemini 6 with Gemini 7, and later first docking of Gemini 8 with unmanned Agena Target Vehicle) that the dynamics of the in-orbit rendezvous and docking aren't exactly intuitive. You can't simply apply thrust in the velocity vector to catch up with your target vehicle, because that will add energy to your orbit and you'll end up increasing your altitude and with it distance to the target. And we also know that stationkeeping in Lagrange points isn't anything like orbiting around some massive body and halo or Lissajous orbits are the usual approach to maintaining one's position relative to L-points. So here's my question:
With Lagrange point stationkeeping requiring entirely different approach to maintaining attitude than when in orbits around parent bodies, do we sufficiently understand flight mechanics of EML2 rendezvous and assembly / docking? Have we already done anything like it, run extensive physics simulations, or will proof of concept missions be required before risking billions of dollars of hardware on a manned mission to Mars and do that first as soon as it's required, if it indeed called for EML2 assembly?