Quote from: meekGee on 07/12/2017 07:29 amQuote from: guckyfan on 07/12/2017 05:30 amI have no idea if it will be done. But it would secure the stage on the barge, better than the Roomba/Octocrab can. It would make turn around easier than with legs. They could be on the way back an hour or two after landing. It would save some weight. But can they come down precisely enough that the thrusters can do the fine tuning? The last two landings at the limits of what can be done, were not that precise. We will see if they can improve at the limits with practice.I wonder if they could modify the He-pressurization for the legs for at least initial tests, before they install cold gas thruster in the thrust structure area.IMO the catching mechanism will have a substantial structure, both for last-inch alignment, and for arresting vertical motion (which the legs kinda do today).That said, there are some advantages for doing it far off shore.I think it could be a substantial, but simple system. I've attached my pet idea of using counterweights on 'see-saws'Getting it out of there without relaunching would require a crane, but so do the legs.F9 doesn't have a frustrum like that on the end, but it's just an example, and any GH type flight would just be for experimentation anyway so there'd be a lot of modifications to get it working.
Quote from: guckyfan on 07/12/2017 05:30 amI have no idea if it will be done. But it would secure the stage on the barge, better than the Roomba/Octocrab can. It would make turn around easier than with legs. They could be on the way back an hour or two after landing. It would save some weight. But can they come down precisely enough that the thrusters can do the fine tuning? The last two landings at the limits of what can be done, were not that precise. We will see if they can improve at the limits with practice.I wonder if they could modify the He-pressurization for the legs for at least initial tests, before they install cold gas thruster in the thrust structure area.IMO the catching mechanism will have a substantial structure, both for last-inch alignment, and for arresting vertical motion (which the legs kinda do today).That said, there are some advantages for doing it far off shore.
I have no idea if it will be done. But it would secure the stage on the barge, better than the Roomba/Octocrab can. It would make turn around easier than with legs. They could be on the way back an hour or two after landing. It would save some weight. But can they come down precisely enough that the thrusters can do the fine tuning? The last two landings at the limits of what can be done, were not that precise. We will see if they can improve at the limits with practice.I wonder if they could modify the He-pressurization for the legs for at least initial tests, before they install cold gas thruster in the thrust structure area.
Quote from: spacenut on 09/06/2017 02:16 pmHow much payload capability would F9 have without legs?The usual shorthand math for first stage weight reduction is that ~10% of that removed mass is added payload to orbit. So... The 4 legs weigh around 2.5 tons, so removing them would add 250kg to the payload. So not much.Removing legs is more about operational simplicity and rapid turnaround than it is about adding payload capability.
How much payload capability would F9 have without legs?
I vote for bees.
Why are people ridiculing this? Landing without legs is an idea that should be taken very seriously, it is based on something that Elon Musk actually showed on stage. It wasn't so very long ago that landing at sea was ridiculed but then SpaceX announced they were going to do it and then did it successfully multiple times.The current F9 landing legs are detachable and optional. It would not be unreasonable to design a separate landing gear that is lighter and designed to be "grabbed" by heavy equipment on the ground instead. Since all of this happens without customer payloads on board it is relatively easy to experiment and SpaceX can easily afford to lose some recoveries.
....If they do a cradle, I expect them to make it the rocket's responsibility to get darn close to the cradle and the cradle to compensate for a meter or two max. No lassos, inflatable catcher's mitts, sky hooks or giant chop sticks.Maybe bees though. The bees have real potential. I'm hearing a lot about bees lately.
Quote from: mme on 09/22/2017 11:40 pm....If they do a cradle, I expect them to make it the rocket's responsibility to get darn close to the cradle and the cradle to compensate for a meter or two max. No lassos, inflatable catcher's mitts, sky hooks or giant chop sticks.Maybe bees though. The bees have real potential. I'm hearing a lot about bees lately.Exactly. The F9 will do it's job and the cradle will be active and will very quickly make up the last distances in 3 axis's. Maybe less than a meter.What technology it would use to sense the stages position through rocket exhaust would/will be interesting.Regarding Bee's people are saying great things about the bees, they are huge bees, the best bees.
Quote from: wannamoonbase on 09/26/2017 06:00 pmQuote from: mme on 09/22/2017 11:40 pm....If they do a cradle, I expect them to make it the rocket's responsibility to get darn close to the cradle and the cradle to compensate for a meter or two max. No lassos, inflatable catcher's mitts, sky hooks or giant chop sticks.Maybe bees though. The bees have real potential. I'm hearing a lot about bees lately.Exactly. The F9 will do it's job and the cradle will be active and will very quickly make up the last distances in 3 axis's. Maybe less than a meter.What technology it would use to sense the stages position through rocket exhaust would/will be interesting.Regarding Bee's people are saying great things about the bees, they are huge bees, the best bees. Well, assuming that they put up some lightening towers around the landing sites, (surprised nobody has considered what kind of a lightening rod a landing stage would be) small radar units could be installed at a far enough distance and height to triangulate the exact position of a stage as it descends. this data would be relayed to the capture device, which would move and elevate to compensate appropriately. Simple solution really.