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Is the Starship Mk1 more structurally sound than it looks? From a first glance and having no knowledge of its design, it looks like an empty soda can that would
by cracker_jacks 7y ago
Is the Starship Mk1 more structurally sound than it looks? From a first glance and having no knowledge of its design, it looks like an empty soda can that would deform at the slightest disturbance. And the way it crumpled in the video doesn't seem far off from what I would expect.
- MattRix 7y agoYes, your impressions are wrong.
- JshWright 7y agoNot really... a soda can is a pretty good analogy, actually.
- roywiggins 7y agoRockets are actually pretty easy to poke holes in. They're meant to keep stuff in, not out. A dropped torque wrench blew up a Titan. https://en.m.wikipedia.org/wiki/1980_Damascus_Titan_missile_explosion https://en.m.wikipedia.org/wiki/1980_Damascus_Titan_missile_...
- mlyle 7y agoAn 8lb socket dropped 80 feet. That's going to put a heck of a dent in almost anything.
- war1025 7y agoAssuming I remember my high school physics correctly, the socket would be moving ~50mph on impact. Definitely a recipe for a bad day.
- jml7c5 7y agoFor reference, the average human seems (from a very brief search) to swing an 8lb sledgehammer at ~25mph. So it's a bit like someone very, very strong (think strongman competitions) nailing the thing as hard as they can with a sledgehammer.
- Someone 7y agoIt would be a glancing blow, though. Bad, but not as bad as a blow striking orthogonal to the surface.
- jml7c5 7y agoAh, good point. For some reason I was imagining the rocket lying on its side or some nonsense.
- mlyle 7y agoIt wasn't a glancing blow. It solidly struck a thrust mount and then bounced to pierce the tank. So while some energy was lost in the collision with the thrust mount (how elastic was it?) the blow that counted was dead-on.
- ncmncm 7y agoThen the fuel just drained out for a long time. Long enough for the guy to dawdle before telling anybody, and then to get orders from higher-up, and for everybody to high-tail it out of the complex. Not far enough, though.
- war1025 7y agoExcept the guy they sent back in to turn on an exhaust fan that arced and blew everything up... Poor bastard.
- glup 7y agoThere's also a fantastic This American Life about the incident: https://www.thisamericanlife.org/634/human-error-in-volatile-situations https://www.thisamericanlife.org/634/human-error-in-volatile...
- contravariant 7y agoIt's somewhat impressive that the actual nuclear warhead didn't so much as leak. Which is what's supposed to happen but still you don't usually design something to withstand a botched missile launch capable of 'catapulting' a 740 ton door.
- azernik 7y agoOnce you've already designed something to survive a very steep and fast atmospheric re-entry with delicate electronics intact, it's going to withstand other kinds of punishment pretty well too.
- missosoup 7y agoThere wouldn't be much to 'leak'. The nuclear material in weapons is relatively safe to handle as long as you don't ingest it. It's the post-explosion fission products that are nasty. Also with nuclear weapons, as much engineering has gone into safety as into weapon design itself. It's astronomically improbable for a modern nuclear weapon to detonate prior to arming even if the explosive lens is set off. The reentry vehicle is designed to come down at circa mach 14 so a little bit of heat and jostling isn't going to bother it. Cool video about some of the engineering involved: https://www.youtube.com/watch?v=97t7Xj_iBv0 https://www.youtube.com/watch?v=97t7Xj_iBv0
- ncmncm 7y agoThe word "safety" in connection with nukes has been redefined to mean "it blows when you push the button". So the DOE's responsibility to maintain the "safety" of the arsenal sounds much better than it is. Not blowing up when you don't push the button doesn't have a name. When they actually dropped a pair by accident from a B-52, both got very far into their ignition sequence before something failed. Questions were Asked, after. So it is probably better now. Here. Russia? Israel? India? No telling.
- missosoup 7y agoYou're talking about an incident involving a mark-39 bomb which was built in the 1950s, the same time period when USA ran reactors with a man wielding an axe to cut rope to drop control rods as an emergency shutdown measure. We have come a long, long way since then in nuclear safety both in weapons and reactors.
- LeoPanthera 7y agoNon-mobile URL: https://en.wikipedia.org/wiki/1980_Damascus_Titan_missile_explosion https://en.wikipedia.org/wiki/1980_Damascus_Titan_missile_ex...
- ablation 7y agoI find the mobile view a lot easier to read on my laptop, funnily enough. I've started preferring mobile links to wikipedia lately.
- CydeWeys 7y agoSoda cans are actually incredibly strong for their weight.
- the8472 7y agoYou don't want your rocket to be heavier than necessary. They're usually dead weight once in orbit. So yes, they're a bit like a soda can. Just as strong as necessary.
- JshWright 7y agoYou're not wrong that Starship has very thin walls, but they're actually quite thick compared to some rockets. There are rockets in use today that have to be pressurized to avoid collapsing under their own weight.
- manicdee 7y agoYes, rockets are basically soda cans full of propellant with rocket engines on the bottom and the payload usually on the top. They are entirely constrained by thrust versus mass, so the designers make the structure as light/thin as possible while still being able to handle the acceleration forces when fuelled and pressurised. If the weight of the rocket itself is too high it will not be able to lift any payload. If it is too light it falls apart in flight (or in one spectacular case, crumples in on itself when pressurisation fails).
- fsagx 7y agoAtlas booster: https://www.youtube.com/watch?v=imkdz63agHY https://www.youtube.com/watch?v=imkdz63agHY
- errantspark 7y agoYou're actually spot on. For example the Space Shuttle main tank had a 96:4 contents:structure ratio[0]. A soda can is 94:6. [0] https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html https://www.nasa.gov/mission_pages/station/expeditions/exped...
- dehrmann 7y agoHow does that compare to commercial airplanes?
- errantspark 7y agoI'm guessing something in the 3:2 range on payload to structure ratio.