The main issue with down range recovery, at least as far as SpaceX is concerned, is that it doesn't work for the "rapidly" part of Elon's often stated "Fully and rapidly reusable" mantra.
How much risk NASA and ULA do/should take is off-topic for this thread.
A really big catamaran would be easy and cheap to do, say 100mx100m would only cost a few millions (100m barges cost as little as 2-3million)
SWATH boats are smoother than traditional displacement hulls, but they're still moving plenty in multiple axis. Their stability is most evident upon being under way, which makes for a moving target.
And if "downwind" involves taking wave action at a bad angle your SWATH landing pad will be bouncing around quite dramatically.
The building contract for Silver Cloud was most unusual in that itspecified the maximum vertical acceleration acceptable. For comparison,NATO naval vessels require a maximum of 0.2g rms (1g = force ofgravity, rms = statistical average), a standard hardly ever achieved inpractical operation by ships less than 100 metres in length. On trials in atwo metre head sea, Silver Cloud recorded a dramatically smaller verticalacceleration of 0.035g rms. The roll angles were also very low at 1.2degrees rms in beam seas.
Make note here. Landing on a hard vessel deck is _worse_ than landing on land. If you catch a boat on an upswing your impact speeds are even worse than landing on land. If you're going to land on a hard surface anyway, just land on land.
Just because it's feasible doesn't mean it's a good idea. Using landing legs its better. It gives a better margin for a safe landing if there is an error, or a gust of wind or something.
Except during earthquakes the typical rms acceleration (vertically AND horizontally) of land is 0.000 g
Quote from: deltaV on 03/28/2013 12:52 amHow much risk NASA and ULA do/should take is off-topic for this thread.My apologies, you're correct.
Q: How will v1.1 booster recovery be attempted?Musk: Initial attempt with water landing after ballistic arc, burn before atmosphere to reduce speed, then 2nd burn before splashdown. We don't expect success in the first several attempts. Later we will try to return booster to launch site with landing legs.Q: First attempt to bring 1st stage back to launch site?Musk: Not a specific flight, perhaps middle of 2014
For v. 1.1 and Falcon Heavy boosters, sure. But I'm still skeptical they can do it with the Falcon Heavy core.
Quote from: llanitedave on 03/28/2013 05:36 pmFor v. 1.1 and Falcon Heavy boosters, sure. But I'm still skeptical they can do it with the Falcon Heavy core.I'm reserving judgement on the FH core. Seems very difficult no matter how you slice it since it won't have a full heat shield.
Perhaps boost forward to Vandenberg landing site may be more likely for FH core
Quote from: oiorionsbelt on 03/28/2013 07:06 pmPerhaps boost forward to Vandenberg landing site may be more likely for FH coreReentry would be brutal. That would be more than half way around the world - very close to orbital velocity.
yes, similar to second stage re-entry, which they are also working on.
Quote from: oiorionsbelt on 03/28/2013 07:42 pmyes, similar to second stage re-entry, which they are also working on.The second stage gets a full heat shield and is much shorter. The penalty for doing this on a full first stage seems prohibitive.