Interesting concept, but – as others said – it seems rather hacky. Sure, from one engineering perspective it's straightforward to only collect the engines. Othe

Interesting concept, but – as others said – it seems rather hacky. Sure, from one engineering perspective it's straightforward to only collect the engines. Others say that re-assembly and especially the proposed collection process adds its own complexity. I think that the collection process is more involved (concerning number of "moving parts", i.e. requiring a number of independent systems to work in perfect synchronicity) than what SpaceX does. The F9R does have a more complex navigation and guidance system due to the landing option. But apart from the fins and legs[1] (which are of minor complexity), there's no additional subsystem required for the landing capability. Everything's already there and used in other parts of the launch – including major parts of the landing navigation and guidance system. And SpaceX could launch another F9R with the same 1st stage on the same day – ULA would need days, at least. So I think ULAs approach is over-engineered and does little to improve on the idea of launcher reusabilty. [1] Actually, the legs may be used before launch in the future, so one less surplus subsystem ;)