I can't come up with a scenario where the BFR ship would make an emergency water landing. (Of course, it could just be that I lack knowledge or imagination.) Airliners can do them because they glide, so water landings are a possibility after fuel exhaustion or engine failure. BFR won't glide well enough to land softly, so it would have to be a propulsive water landing. And if you can land propulsively in the water, surely you can land propulsively at the landing pad.
> if you can land propulsively in the water, surely you can land propulsively at the landing pad.
I think if you take off and you immediately find that one of the rocket motors isn't gimballing correctly, or something else looks off with the engines, it might be prudent to abort before building up a lot of velocity. (not to mention aborting before something explodes) It's certainly easier.
I don't think that's always going to be possible, but yeah, that's probably the first choice.
I imagine the most problematic abort in something like a NY to London flight would be if multiple engines fail several hundred miles out. All kinds of velocity in the wrong direction if you want to fly back, not enough thrust to maintain the proper trajectory towards the target. I think there are bound to be some scenarios where you can do a limping, powered landing (the vehicle probably only needs one or two working engines) but you have to do it downrange.
I'm not sure that the ship would be strong enough to withstand a water landing. It'll come down on its tail, and then it will (I think!) tip over, which will probably smash it to pieces.
Aborts also leave you with too much fuel on board, probably way too much fuel. You could burn it off with the engines, although you'd want to actually use it to reach your origin or destination if possible.
If you abort early, you can still reach the origin. If you abort late, you can still reach the destination on the remaining engines. So the pertinent question is: do these two regimes overlap, or is there a gap, and how big? I don't have the answers, and you may be right that there is one.
