> Bringing the 1st stage nearly to a stop at some point mid-air should be way easier than landing it on the ground. One thing to note about Falcon 9 is that it

> Bringing the 1st stage nearly to a stop at some point mid-air should be way easier than landing it on the ground. One thing to note about Falcon 9 is that it's impossible for it to hover since its thrust-to-weight ratio is greater than 1 at the time of recovery, even at minimum throttle. So you have to do a suicide burn such that you zero out velocity at your target. Someone already pointed out the problem with helicopters capacity compared to the Falcon 9 weight. The idea is not without merit, However. ULA is considering a similar approach for the Vulcan. The big difference is that they plan to eject the engine core and catch only the engines with a helicopter. See http://spaceflightnow.com/2015/04/13/ula-unveils-its-future-with-the-vulcan-rocket-family/ http://spaceflightnow.com/2015/04/13/ula-unveils-its-future-... The downside of this plan is increased complexity. Falcon 9's approach requires fins, some landing struTs and software. ULAs approach requires a system to eject the core, a shield for the cores re-entry, a parachute, a helicopter, and impeccable timing. I'm guessing that catching a parachute with a helicopter is an incredibly difficult problem just by itself. I would suggest that you watch the Vulcan development to see how your thoughts play out. Regarding the pool, I would assume that the issue would be finding an inert liquid, putting it in the middle of the ocean stably and enough quantities for a landing, and then getting the rocket into the liquid without damaging it. You'd likely still have all the same problems as just landing the rocket -- you have to zero horizontal elicits or the thing tips over and impacts the liquid too hard, and you have to zero verticle velocity or your impact is too hard. Ultimately you might as well just land the damn thing, which is also more versatile.