That's absolutely another major concern. I can't tell if they've designed their centrifuge to also provide structural support, such that I guess only an outer sleeve of the thing is able to rotate. Because, strangely, we're not afforded a view inside the latest build. And if I were there, in person, I'm not getting anywhere near that thing when it's running. So they're like "Hey we can pump down really quick, it's only a rough vacuum". Well, guess what the pressure differential is between 760 Torr and 1E-7 Torr vs. 760 Torr and 1E-3 Torr? Just about 760 Torr, for both. You've got 1 atmosphere trying to implode the thing (love the music). Yeah, the thing will have to live in a web of buttressed supports outside of it. Ideally, you want to cut a vacuum chamber from a single hunk of steel. There's not a forge in the world that has a 45 m radius capability, I just checked. ~15 m seems to be the current record. Not even close. So you'll unavoidably have welding joints in the chamber walls, and you'll have to pass through resonances with chamber vibration modes as the centrifuge spins up or down, with atmosphere pushing in from all sides. Cool, seems fine. Ideally, you'd want the walls to be thicc af, but... how do you weld something super thick together? Genuinely asking. Surely the steel you're fusing together only extends maybe 1/4" or 1/2" into the steel, right? Ladies and gents, I present to you - The Theranos of the space industry.
Dude. 5:33. Whizzy spinny arm. Watch the sun. They shot that shit timelapse They aren't even in the regime of approximation here. They straight up welded up a beer can, got a motor spinning, and then broke the shit out of it. Probably when they let their load go in an insufficiently synchronized fashion and smashed the bearing first one direction and then the other. Does it really matter? They pretty much need it to be vacuum from launch to the Karman Line or else they're fucked. There's no aspect of their design that indicates they've even done wind tunnel tests. They haven't so much as watched a redneck sandcasting aluminum with a propane torch. "Mach 6" is a phrase for them, not a fluid regime. The thing that blows my mind about that video is the only stuff that we didn't call out a year ago is stuff that is actually worse.
Thanks, I gave up after a while of scrubbing through the vid. Blink and ya miss it, eh? So, no support along the chamber axis of symmetry, yet. LOL Hey, here's another entire thing we haven't ragged on yet: The orbit!! You get one orbit per facility. But you can steer a first stage rocket quite a few degrees by gimbaling the engine to one side. And now I'm in stitches trying to imagine attempting to steer a spunlaunch with little thrusters in the lower atmosphere. I'm sure they'll target geosynchronous orbit, since that'd be the most in-demand. But, like you said, who cares? It doesn't matter. It really doesn't. Yeah I was cruising that first thread from 900-odd days ago and feeling like a smug bastard. It's good that this place is pseudonymous because these are the types of companies that'll go after you for "slander", I'm sure.5:33
The thing that blows my mind about that video is the only stuff that we didn't call out a year ago is stuff that is actually worse.
Oh god. You're right. You're putting it in that spot, that spot right there, that's the spot you're putting it in. Theoretically second-stage is a full-on rocket (so, like I said last time, why bother with the fuckin' tilt-a-whirl) so you can do rockety stuff with that stage, but this is a bunch of people who flew their one and only drone into the ground in 2015. That said, I don't think it will get to geosync, dude. They're claiming 200 kg "to orbit" but you know that's LEO. That means they're prolly like 70kg to GTO. What the fuck do you do with that? Their entire embarrassing website makes much of cubesats but really - what the fuck do you do with cubesats other than make your community college proud?Hey, here's another entire thing we haven't ragged on yet: The orbit!! You get one orbit per facility.
btw everyone, GTO is geosynchronous transfer orbit, but if you don't know LEO, delete your account. For sure, the second stage could (very theoretically, after 182 Falcon 9's) perform some corrections, but the changes would have to be comparatively minor. Maybe the best way I can explain the mechanics simply is to point out that the most efficient orbital inclination corrections are performed near apogee, after orbit has already been achieved, and the spunlunch first stage does not even make it to LEO orbit with YOUR 182 FALCON 9 MOM!!! onboard. Presuming you couldn't steer the "first stage" spunL equivalent. (you can't; your mom) Unless they build a luncher near the equator? Best of luck with the 10k g's compliant gimbal system or any other scheme whatsoever to park longitudinally in GEO without roving +/- 30 degrees of latitude every orbit or two or so. Now, imagine the military contracting SpinRanch to put something in low latitude LEO. That's all, that's this paragraph, I hope you enjoyed it. Thank you. Time for minor NASA sacrilege. There is a case to be made against the current paradigm, I will confess. Many things could benefit from serious miniaturization. But many things are very difficult to miniaturize further. Many things should just be shot up into space with way less testing, b/c diminishing returns. Sadly, institutional reputation prevents a bit of progress, for now, cubesats and microsats aside (if only relatively). Everything's all over the board, but the idea that any scientific, military, comms, seriously ANYfucking type of payload can be both miniaturized and 10k g's hardened, and the SpinLaugh scheme would make up for for the hit$ you'd be taking is so fucking hilarious that this is legitimately embarrassing for the current culture of American capitalism's distrust of expertise. There was even a small part of me that was like "wow, this almost kinda diminishes from the respectable successes of the SpaceX business model", but I just cut off both my baby toes, and I'm feeling a lot better. #subsideezNUTSwhat the fuck do you do with cubesats other than make your community college proud?