This is a very well done concept, I especially like the modularity of the orbiter vehicle, which should allow the A and B modules to be tested aboard the Ariane prior to full system testing, and the full Aries and Lira vehicles can be independently flight tested as well. I also like that it's not trying to be all things to all customers, as what happened with STS.<br /><br />ARIES-C can be left in orbit while A/B mates with a lunar transtage.<br /><br />One question: there should be an unwinged/unmanned version that just recovers the propulsion module of ARIES, dumping the tanks and cargo doors. It seems that this is only meant for passengers, unless you intend to launch satellites through the airlock door... <img src="/images/icons/wink.gif" />