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Somehow I suspect they have run the numbers.
by d_theorist 10y ago
Somehow I suspect they have run the numbers.
- sandworm101 10y agoWhat numbers? Unsecured cargo is unsecured cargo. A metal object sitting on a flat metal deck gets tied/braced/chained.
- d_theorist 10y agoI think you're trying to apply rules designed to govern shipping in general to a very specialised and controlled situation.
- stcredzero 10y agoA lot of rules around shipping actually have to do with physics. See my other comment. Shifting cargo can be very bad news. It has caused a lot of deaths. It's probably not a big deal in this case, except that booster is worth about (I'm guessing) 20 million dollars, SpaceX's cost? It's tall, but the center of gravity is low and it's on a barge. Engineering is conservative "just in case." So are a lot of practical activities that happen on the sea. In neither case, is this irrational or a waste of time.
- sylvinus 10y agoThey mentioned multiple times that because the stage is empty, its center of gravity is much lower than what you'd expect.
- fixermark 10y agoBy whom? The drone ship has no on-board crew. ... which means there's nobody around to be injured or killed if the rocket falls post-landing. Maybe it's a precaution worth taking when they intend these stages for commercial re-use; for now, the whole thing is one big experiment.
- skykooler 10y agoThere is a ship a few miles away with engineers on it. Once the stage has vented all excess liquid oxygen and is safe to approach, they can return to the ASDS and secure it.
- andygates 10y agoThey will of course have modelled the cargo scenario, and I suspect that Musk means that it's nice and stable when they do that -- but then shipping norms come into play because, like you say, unsecured cargo is unsecured cargo. It needs to be both stable and secured, because only one is inviting woe.
- est 10y agoBy the time the rocket lands, there's very few fuel left, basically you see a near empty Pepsi can. It's as stable as it can get.
- sandworm101 10y agoEver see an empty pepsi can in a stiff breeze?
- blater 10y agoMore like a Pepsi can with a bloody big brick in the bottom 9*470 kg merlins). Main threat to stability would seem to be wind, but doesn't seem to be the case in practice
- rz2k 10y agoJust to elaborate: due to wave action and leverage on the underside of the hull, parts of the deck of a ship can accelerate downward faster than the acceleration from Earth's gravity, and while the deck underneath the rocket has fallen faster than the rocket and its heavy engines it can also lurch to a side. Even if the center of gravity makes it equivalent to a sheet of rolled steel, so that it wouldn't tip over, it could become displaced, then go overboard or cause unwanted damage. While I suppose that the rocket could be heavy enough to lower the center of gravity of the entire vessel below the troughs of any waves enough to make it incredibly unlikely, it isn't just the prospect of tipping over that makes it important to secure cargo.
- zardo 10y agoOf course if there is any chance of the rocket moving, it isn't even safe to pull up alongside, let alone send people onto the deck to secure it.
- sandworm101 10y agoThere are protocols for securing unsecured cargo. Whether delivered by rocket or crane, things land on decks every day and are tied down by hand.
- beachstartup 10y agohow much money and time would a robotic lashing system cost? hint: a shitload. how much money would a few ditched rockets cost, in comparison? hint: less than a shitload would a recovery crew approach this platform in rough seas, even if a robotic lash were in place? hint: nope then what exactly is the point of securing this 'cargo'? hint: there isn't one. problem solved.
- rblatz 10y agoWhat port will let them in with giant explosive unsecured cargo? Hint no port.
- beachstartup 10y agoand yet, they seem to be doing just fine.
- rblatz 10y agoEverything I've seen says they secure their load. Is there something I'm missing?
- beachstartup 10y agoi'm referring to the landing platform.
- manicdee 10y agoThe point of securing the cargo is to prevent it being lost to toppling, sliding off the side, or being catapulted off the side of a rolling deck. And yes, it will be secured. The previous recovered rocket was secured, this one will be too.
- beachstartup 10y agoi'm talking about the landing pad.