So you're thinking these are the support arms for a set of "bouncy castle walls" that funnel the faring(s) into the centre?Yes. A “net” approach (my first assumption too) has problem that I am trying to work around:1. You cannot catch both fairings at once without potential interference. 2. You cannot catch both sequentially without potentially damaging contact of one fairing landing and laying on the other.3. Any scheme for moving one out of the way or somehow protecting it, and then catching the other to avoid 2 will have to be completed very quickly. It’s hard to imagine the degree of control over the timing of the landing via alternate parachute paths, or Angle of Attack, exceeding a minute, but this is just a guess
Quote from: FutureSpaceTourist on 12/26/2017 08:55 amTo me inflatable structures seem quite a bit more hassle to operate and maintain than appropriately tensioned nets. It’s not clear to me how significant the benefit(s) of using inflatables?Agreed. The four arm structure, to me, says "non elastic web".If there's controlled give to it, it's created by controlling the tension in four cables coming down from pulleys at the apexes using brake winches.
To me inflatable structures seem quite a bit more hassle to operate and maintain than appropriately tensioned nets. It’s not clear to me how significant the benefit(s) of using inflatables?
Quote from: meekGee on 12/26/2017 10:20 amQuote from: FutureSpaceTourist on 12/26/2017 08:55 amTo me inflatable structures seem quite a bit more hassle to operate and maintain than appropriately tensioned nets. It’s not clear to me how significant the benefit(s) of using inflatables?Agreed. The four arm structure, to me, says "non elastic web".If there's controlled give to it, it's created by controlling the tension in four cables coming down from pulleys at the apexes using brake winches.Looking closely at the ship rigging, it could be that the port pair and the starboard pair deploy 'bouncy castles' to their respective sides of the ship. The forward arms look to be articulated in the lower section (shown straight in the image) and the aft arms look like they have a brace on deck for them to rest on when lowered past horizontal outboard. This would create a pair of landing beds nicely separated by the width of the ship.https://forum.nasaspaceflight.com/index.php?topic=37727.1020
If you were designing a general purpose cradle landing structure that could also be used for dragon capsules as well as fairings then could this be it? I could imagine the attempt being made for the cargo version. I'm assuming that avoiding salt water might be a good thing, even for something designed for it.
Landing a Dragon on a dry net would probably be super helpful, the heat shield and the many Dracos would be in much greater condition than they would be in saltwater.
Quote from: IanThePineapple on 12/26/2017 04:26 pmLanding a Dragon on a dry net would probably be super helpful, the heat shield and the many Dracos would be in much greater condition than they would be in saltwater.Would the netting material need to be heat resistant? Does the heat shield have sufficient time (the airflow presumably is good) to cool down? What about the thruster ports? (if not fired, then presumably yes?)
Would several minutes under a parachute be enough? The heat of reentry is intense, but relatively short duration.
Mr. Steven is a relatively fast moving vessel for its size. If you attach any number of large bouncy castles to the rear of the vessel (in the water or suspended in the air), then she won't be able to utilize her speed due to the increased drag
What about rebound? Even if it's moving slowly, something that big is going to land with a lot of energy, is there enough room to absorb it all or how could they keep the fairing from impacting and not bouncing off?
That is not reusable though, better to use the types of ropes used in climbing. In those the core of the rope is heat treated to make it crinkly. If a force is applied then the crinkles unfold to allow the rope to stretch. The normal ammount of stretch is 10% but it can be 30% or more. There is zero rebound. In climbing the device described above is referred to as a screamer, it's used in situations where above a fixed amount of force the whole system would fail. To catch a falling fairing I'd make a net out of dynamic rope (climbing rope) attached to the arms (as on Mr Stephens) with screamers. In normal operation the net alone would provide all the cushioning needed. In extreme situations the screamers would be triggered to protect the arms from failing but still allowing the fairing to be captured.
If the braking winch is electric, you actually have a record of how gently the fairing was caught, what was the maximum g on it, etc. Crossing a certain limit would trigger a more detailed post-catch inspection. (or actually any form of strain gauge would do)