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comment by kleinbl00

Yes but if we're trying to defeat "the tyranny of the rocket equation" let's fuckin' defeat that bitch, shall we? No "stages" we're zero-stages-to-orbit, goddamn it.

What's funny is if you're willing to just accelerate in a straight line at 1.5G, you're at 10km/s after like 3200km. Which starts to make that rocket look positively frugal. 3Gs and I'm at 1300km, 10gs and I'm at a nice benign 100km track.

10gs is going to involve some compromises, for sure. You're probably not going to be higher than 10,000ft which is a bummer and which means yeah, you're going to need a second stage prolly. But you've got load in one direction, you've got it for a little over a minute and a half, you have no release mechanism to worry about, and aside from the heat of friction and the (substantial) complications of fluid mechanics, you're squarely in the realm of normie physics. It's a Grainger problem not an Unobtanium problem. Fuckin' Gerald Bull got 84kg 80km past the Karman Line with fucking cordite.

There's no real way around the fact that the minute you leave the barrel you're slowing down. But there's also no real way around the fact that the minute you decide to go in a straight line you solve almost all of your problems.

    At this point, I'm surprised more people aren't speaking up about how much of a blatant scam this is.

The minute they take public money it's over. Theranos would be much less of a cautionary tale if (A) they didn't bait the Army into evaluating their bullshit (B) they didn't give a bunch of Walgreen's customers spurious "you're going to die soon" test results.





am_Unition  ·  835 days ago  ·  link  ·  

I got used to designing things for orbital flights, with those ~1.5 g accelerations. You don't even think about the static load, it's entirely about the noise / random vibrations environment. Then I did a sounding rocket, and the lead scientist forgot to mention that there's a 10 g static load on top of the noise. Those suckers really fire off quick, which is fantastic when you're trying to fly through a very dynamic auroral feature, but yeah I ended up putting in these ugly little splints at the last second to shore up some problem spots. No software analysis, and no QA, because sounding rockets are too cheap. Quick peer review. Worked like a charm.

The idea of designing scientific instrumentation for a Mach 6 noise environment a few milliseconds after the jerk of -10,000 g's over 0 seconds (hopefully it's 0 seconds, for attitude control! Hey does anyone know what happens when you divide something by zero?) reverberates through my shit is so funny that I can't wait to talk about it with my old boss.

Drag. It's proportional to the square of the velocity, and inversely proportional to altitude. Having the fastest portion of your "first stage" SpinLaunch equivalent while you're at your lowest altitude is so stupid. So, so stupid.

    Fuckin' Gerald Bull got 84kg 80km past the Karman Line with fucking cordite.

Sure, but they shot almost straight up. So at (suborbital) apogee, the projectile had about zero velocity tangential to the axis connecting the projectile to the center of Earth. SpinLaunch will need to be angled only maybe 20 degrees or so above the horizon. The fact that their only field test facility was flinging shit straight up doesn't bode very well. Yes, a rocket begins by going straight up, but then angles over to push your tangential velocity up. The vertical-ish part of a rocket's ascent also gets you out of the thickest part of the atmosphere quickly, too. Meanwhile, ScamLaunch needs to travel through muuuuuch more atmosphere because of the release angle being close the horizon. There's no getting around that.

I feel like the NASA evaluation they've committed to is plenty enough taking of public monies for me.

Seriously, a space elevator is such a better direction to push in than this, and I'm not totally convinced that's feasible either. I wanna see how quickly tectonic drift becomes problematic, for starters. You gotta keep it dead center of the equator. If we could make the top anchored to a captured, well-controlled asteroid parked in GEO? Might work. We'd have no choice but to de-orbit shittons of space junk, tho. I still think a moon base shooting UV or even X-rays to de-orbit junk when facing the Pacific, once a day, is the best solution I've come up with, or heard anywhere, for that matter. The tracking software should... cost a few $'s.

kleinbl00  ·  835 days ago  ·  link  ·  

    Having the fastest portion of your "first stage" SpinLaunch equivalent while you're at your lowest altitude is so stupid. So, so stupid.

Yeah, I know. my X Minus One heart really wants this to work on some level? For there to be some way to bend the equations to vanquish Tsiiolkovsky? But I mean... it's not like clever people haven't contemplated this shit for a while now.

Gerald Bull was in it for the artillery, pointing shit at space was just the easiest way to get funding (until it became "pointing shit at Israel" at which point the Mossad, er, revoked his grant). I am fully aware that vanishingly few ballistic objects execute a 90 degree turn halfway through their path.

This is why you must design for 10,000g apparently.

am_Unition  ·  835 days ago  ·  link  ·  

I really hope that pic is from actual promotional material, and not a Broadway show or something.

    This is why you must design for 10,000g apparently.

That's alright, I'm OK.

kleinbl00  ·  835 days ago  ·  link  ·  

Pretty sure it's a production still.

am_Unition  ·  835 days ago  ·  link  ·  

That's Amoré af.

"Moon hits your eye"?

Shoot her in the eye right back.

- SpinLaunch™

P.S. yeet