In the press conference after Musk said that when the rocket was vented and safe a team would board the barge and weld ‘shoes’ over the legs to secure the rocket, then tow he barge to the Cape to unload it.
I have a hard time thinking how the rocket stage can remain upright until a crew boards and welds the legs to the barge.
How the hell does this thing not tip over?
I read a great analogy by a commenter at Gizmodo:
“To steal a great little comparison I picked up on Reddit yesterday… Glue an empty soda can on top of a brick. It’ll be near impossible to tip over, right? That’s the first stage right now… About 20 tons of engine sitting right above the deck with a whole lot of empty aluminum fuel tanks towering above it. Even the remaining fuel is in the lower tank just above the engines; the upper tank is the LOX and gets vented with helium to safe the rocket after landing. They could probably sail it all the way to port like it is now, but they’ll play it safe and get it welded down to the deck for transport before they move it.”
It has large landing legs that are splayed out, and much of the mass (the engines and Octoweb structure, reisdual RP-1) are all down near the base of the stage. Baring a structural failure of one of the legs it is probably more likely to slide laterally across the barge and fall off the side than it ia to pitch over.
Stranger
If they were smart they’d use wide steel feet and turn the platform into an electro-magnet.
I’ve watched the videos from different angles and my brain refuses to believe they’re real. It just doesn’t look possible.
“Wide steel feet” would add a large amount of weight (the legs are actually graphite fiber broadcloth layups) and making the entire deck a giant electromagnet would be expensive and require enormous power. The engineers who designed the system have clearly performed the basic mechanical stability calculations to assure that the stage will be stable under barge movement conditions, so they seem to be smart enough.
Stranger
yah, I suppose welder’s are cheaper to rent.
The devices, or the workmen?
Both versus the cost of a rather larger electromagnet. I can’t imagine welding something on a moving deck while a rocket sits there but obviously it’s engineered that way.
And there’s probably a good supply of people and gear you could get up to that sort of task, carried over from the maritime salvage and offshore oil industries.
If you really want a means of magnetically holding the legs down, a better approach would be to have small, remote control “cars” that can drive around the deck. They would have large permanent magnets on their underside and a sprung suspension that collapses under the magnetic force. They have a slot in the front that the tip of the legs can fit into. Finally, they have electromagnets stacked with the permanent magnets that can temporarily cancel the field.
When the rocket lands, flip on the electromagnets so that the cars can drive around. Pilot them over the legs, and then turn off the magnets. The cars clamp down to the deck hard with no sustained energy required. Since the magnets only have to be on for a short period, the cars can make do with relatively small batteries.
I was going to suggest that but the welders seemed so much cheaper. Also thought about a peg system where a clamp is laid over the legs and pegged in using something like an oversized cleko fastener. It would make for a quick disconnect.
Fittings are welded down to barge decks all the time, and then cut away when they’re not needed. It’s a very common operation.
Stranger
My concern would be the people, not the welding itself. Obviously SpaceX isn’t going to send anybody out unless conditions are safe, but this could mean a loss of craft if the weather is too bad. That they want to weld on shoes means they’re already concerned about the vehicle sliding around on deck; that necessarily means there could be a scenario where it’s not safe enough for people.
It’s probably a rare scenario, though. I’m sure SpaceX has done the analysis on the likelihood of that happening, given the necessary conditions to land in the first place, and so on.
I would be surprised if they haven’t already practiced the recovery several times with a stage one mockup.
Let me get this straight:
These people just sent several tons of stuff to - a large part of which will come back from, frigging ORBIT, and you don’t think they can weld stuff onto a frigging Barge?!
I saw one story which referenced the “barge”'s underside engines which kept it in relatively one place during the descent.
But, I’m gathering the ship which provides the welding crew (Wow! welding in the middle of the ocean! How exotic!) will then tow the barge/drone/whatever to port.
Notice how high up on the rocket cylinder the legs attach - it would be nice of SpaceX showed a cut-away of the rocket with the legs deployed - that would show theposition of the internal hardware vis-a-vis the leg attach points.
I was at Jetty Park yesterday for the launch. On the roof. Was interesting because the 3 cruise ships…a Carnival, a Royal Caribbean and a Disney… that leave Port Canaveral on Friday afternoon were all departing just as the count down was on.
Have a picture of one of the ships with the rocket and plume just behind it as though it’s launched from the ships bow. Seen many launches as CB= Cocoa Beach. I’m in it for the fireworks and want all launches to be after dark.
Look forward to the coming SpaceX Heavy. Big fireworks I assume.
I slept in (very in).
Did anyone live stream the Dragon’s docking with ISS?
I found an edited-for-length video on NASA - a few minutes to go from tiny speck to at-the-end-of-the-Canadarm close-up.
SpaceX can be annoying - no, I don’t want to replay the launch - I want info on the docking, you twits! :smack:
Was any part streamed live?
Yup, the capture was also streamed live. I watched some of it yesterday morning.
To be honest though, it’s not very exciting… if not for blinking lights on the station and spacecraft, and the Earth in the background, you might not even realize anything is moving during the approach or berthing.
If they were smart? IF they were SMART?!
Dude, they’re rocket scientists.