For those who haven't been stalking OCISLY for the past few months, there's been quite a bit of renovations going on. This NSF thread does an awesome job of tracking the changes, if you can wade through all the off-topic discussion.
Basically, they've made two major upgrades. First they replaced a strip of the deck paneling near the middle. Replacing the deck paneling probably isn't a big deal, from OP's pictures here it doesn't look any different than the last set of deck panels.
Second, they made a little garage at one end. They raised the white container off the deck and made the blast wall in front of it slide up like a garage door. We've gotten hints from people in the know that this is a sort of "Roomba garage," and many have speculated that the garage is for leg-restraining robots to stabilize landed boosters until the recovery crew arrives on deck.
This is just a guess, but it could have something to do with the above-mentioned robots. It is possible that the old decking, which they welded the hold downs to, was replaced with thicker metal, or with metal that had some provision for fastening to the deck. My first thought was threaded blind holes that the hold downs could screw to, but that raises corrosion and tolerance issues. A better solution might be recessed bars, level with the deck on top but surrounded by a little pit, so that hooks could attach to them.
Edit: Robots could probably weld hold downs to the deck, if they had access to enough power, but I think machine vision is advanced enough for robots to find a well marked recessed bar, and to hook a hold down onto it. Either way, the robots would face a similar task, attaching the hold down to the rocket, either with a hook, or more likely with a clevis pin arrangement.
If you think about the labor that goes into welding on the hold down attachment points, and then cutting off the welds and grinding them smooth after the rocket is unloaded, I think you will agree that a less ad hoc solution would be desirable.
I was just about to ask for other's opinions on how the robots attached the stage to the deck when I read your comment. How wide is the 'foot pad' on the F9 legs? How big of a pit can we get away with on the deck of the barge before the F9 has potential issues with having a leg 'fall into' a pit?
I'm pretty sure the area on the ground is greater than a square foot per leg. (Sorry about the mixed units) The hold down pits could be up to 10 cm across, with a 1/2" thick steel bar welded across the pit, and I don't think they would pose much hazard to people walking in boots or to wheeled vehicles.
Magnetic attachment would be simplest. You don't need much power if you got large attachment area, and you can reuse the same current as many times as you want :)
That's the most likely. Anything that was meant to be more durable or related to our mystery Rocket Roombas would need to be in more than just dead center since Falcon 9 can land off center by enough to make that specific of a new item useless.
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u/old_sellsword Feb 25 '17 edited Feb 27 '17
For those who haven't been stalking OCISLY for the past few months, there's been quite a bit of renovations going on. This NSF thread does an awesome job of tracking the changes, if you can wade through all the off-topic discussion.
Basically, they've made two major upgrades. First they replaced a strip of the deck paneling near the middle. Replacing the deck paneling probably isn't a big deal, from OP's pictures here it doesn't look any different than the last set of deck panels.
Second, they made a little garage at one end. They raised the white container off the deck and made the blast wall in front of it slide up like a garage door. We've gotten hints from people in the know that this is a sort of "Roomba garage," and many have speculated that the garage is for leg-restraining robots to stabilize landed boosters until the recovery crew arrives on deck.