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) and could travel downwind on a pre-programmed path to reduce effect of waves and wind - potential for reduced impact of cross winds is actually an advantage over land based landing.If the rocket came in to a hover at a few meters altitude then a fixed grappling hook on top of the rocket could be caught by a wire that swept across at the right altitude, eliminating landing legs, and making it impervious to cross winds. An oversized digger could just about do the job. Simpler still the rocket could just translate itself laterally to hit a horizontal catch wire (their guidance systems are obviously capable). If such a manoeuvre can be done with only 5-10 seconds of additional thrust then it is probably cheaper than landing legs, and the system could be easily transferred to a ship or other relatively unprepared landing site.
Quote from: RobLynn on 03/27/2013 04:44 amA 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) and could travel downwind on a pre-programmed path to reduce effect of waves and wind - potential for reduced impact of cross winds is actually an advantage over land based landing.If the rocket came in to a hover at a few meters altitude then a fixed grappling hook on top of the rocket could be caught by a wire that swept across at the right altitude, eliminating landing legs, and making it impervious to cross winds. An oversized digger could just about do the job. Simpler still the rocket could just translate itself laterally to hit a horizontal catch wire (their guidance systems are obviously capable). If such a manoeuvre can be done with only 5-10 seconds of additional thrust then it is probably cheaper than landing legs, and the system could be easily transferred to a ship or other relatively unprepared landing site.The vehicle will have too much thrust to translate horizontally.
Oh no, not again. Hooks and cables...
Quote from: VatTas on 03/27/2013 08:18 amOh no, not again. Hooks and cables...Indeed. I think this is the third time in the last 2 months this has been brought up.RobLynn. Go read here and the reasons it was shot down. http://forum.nasaspaceflight.com/index.php?topic=30350.msg1000045#msg1000045Edit: I'm new to the huge history of random tests the military and NASA have done in ages past. But why does it seem like every other day someone comes around and says "Look look! They had a test program for it in the past so it must be a good idea to try again!"? This keeps happening.
For the curious the Ryan X13 Vertijet from the 50's was a vtol jet with a nose mounted catcher system, check out 12:30:
which is a sad statement about the times.
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) and could travel downwind on a pre-programmed path to reduce effect of waves and wind - potential for reduced impact of cross winds is actually an advantage over land based landing.
Quote from: MP99 on 03/27/2013 11:33 amQuote from: VatTas on 03/27/2013 08:18 amOh no, not again. Hooks and cables...Some things that were before their time then are feasible now. Cheers, Martin 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. It's also a lot simpler. Everything is a trade. You are already accepting you will lose payload performance when you recover a stage. I think it is much better to accept the extra mass of the landing gear in return for increased assurance of a safe landing. This is about reducing costs, not who comes up with the most complex original idea. A stage which misses the catcher and crashes is worth nothing to anybody.
Quote from: VatTas on 03/27/2013 08:18 amOh no, not again. Hooks and cables...Some things that were before their time then are feasible now. Cheers, Martin
Quote from: meekGee on 03/27/2013 06:21 pm which is a sad statement about the times.No, it's a good statement. We don't need to lose talented engineers by taking stupid risks.
1) I just don't see how down range will work.. once you are there if you can make it you need an army and equipment and logistics to get it back to the factory or Pad area.. I cannot see where the savings will be in reuse when you need so much logistics .2) Once you have boosted yourself downrange your velocity may not be any better than when you started, so you need to turn the stage around to slow down horizontally .. how are you going to turn the stage around.. remember is busy falling into thicker air going downhill. I don't see downrange as a return to launch site as an option..
Quote from: llanitedave on 03/27/2013 06:26 pmQuote from: meekGee on 03/27/2013 06:21 pm which is a sad statement about the times.No, it's a good statement. We don't need to lose talented engineers by taking stupid risks.There is a sweet spot between taking crazy stupid risks, and between being so risk averse that we're even fearful of development failure (as opposed to accidents), CYA rules the day, and the biggest selling point of a proposal is how non-revolutionary it is and how much it "re-uses existing proven hardware".SpaceX did not make a person drive GH first-hand, right? The cowboy was just a joke, and Dragon-cargo is being tested ahead of Dragon-people. Time are different now in some good ways too.But SpaceX is NOT afraid of development failure, has no issue with going back to basics and engineering things from scratch, even if people have to sign their names next to projects that might fail. It's a cultural thing, is led from the top, and is nice to watch.
I've spent more than 25 years in an industry that's not known to be particularly safe (drilling and mining), and I know what things were like in the old days, before management could care two whits about either safety or environmental protection. We're all still paying for some of that attitude. Miner's deaths used to be not worth mentioning, now they're major news and cautionary examples. Needless to say, since OSHA and MSHA seeped into the culture of the industry (and it's still not completely there within some companies I wouldn't want to work for) deaths and injuries have gone way down, and environmental catastrophes have declined tremendously -- yet at the same time mining is more productive and efficient than ever before. Those two facts are not unrelated. The technology of mining has seen great innovation, in large part because of the requirement to protect human safety and the surrounding environment. Yes, mining is more expensive now, but the lives of miners are no longer as cheap, either. It's more than worth the tradeoff.This attitude can and should (and apparently does) apply to human spaceflight as well. As stupendous and inspirational as Apollo was, it was extremely dangerous, and it was in large part a matter of luck that we didn't lose more astronauts and ground crew than we did. Accidents like Challenger and Columbia are no longer acceptable, nor should they be. We have to accept some risk, but we should always be pushing at the envelope of safety as well as capability. Whatever you might like or not like about SLS, I think it's a step forward in that respect, and I'm hopeful that Space X is following that same path. They have to, if the goal of making space accessible to all is ever to be achieved.
