51–60 of 61 posts
Guess we’re gonna have to build our next generation of spacecraft with an inch of milled solid titanium, just like we build our deep sea submarines
Nah, I'm sure some expired carbon fibre will do fine.
From what I can tell looking at SpinLaunch's website and web search, they were founded in 2014, "launched" a couple projectiles in atmosphere, had a leadership change in 2022, and have been pretty quiet since then. Unless I've missed something, the headline "Giant catapult sends satellites into space" is not true. To date, they have not put anything into orbit and the company appears to be on life support.
There's some pretty fundamental problems with spin launch. Atmospheric drag is greatest at sea level, and drops as altitude increases. A traditional lift vehicle is traveling slowest during the early parts of its ascent, and starts reaching high velocity once it's cleared the thicker parts of the atmosphere. In contrast, spin launch is at its highest velocity (before the rocket engine ignites) right after it's releas…
I could see it being a great option for getting bulk goods into space. Fuel, water, food, spools of wire or powders for additive manufacturing, structural components, etc. Depends on what is cost effective. The difficult part would be catching the payloads. It would probably be an even better option on lower gravity lower atmosphere celestial bodies.
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Railguns have always suffered from rail degradation. Basically even if you build a suitably large one, you might get as few as 1 shots from the structure before having to replace the entire rail.
The railgun "solution" occurred to me too. Is the rail degradation a failure of materials science? Or are the materials that would be required for this so theoretical at this point to be science fiction rather than science?
For an actual weapon, this is potentially worth it at a pretty low number since the weapon itself will be pretty small. For a rocket accelerator sled this is going to be more of a problem (but like, conversely you could consider ideas like re-surfacing the rails in place since your turn around isn't fast).
From what I can tell looking at SpinLaunch's website and web search, they were founded in 2014, "launched" a couple projectiles in atmosphere, had a leadership change in 2022, and have been pretty quiet since then. Unless I've missed something, the headline "Giant catapult sends satellites into space" is not true. To date, they have not put anything into orbit and the company appears to be on life support.
They'd have got there already if they'd built a space trebuchet instead of a space catapult.
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From what I could find they have only reached 1/10th of the Karman line. I also think its a red flag that they do not have actual press releases or data, just a list of any random website that wrote a story about them.
SpinLaunch built a prototype back in 2022 that can throw stuff up to suborbital altitudes. The big version was supposed to be done by now. They had a lot of trouble finding a launch site. Hawaii didn't like it. Alaska didn't like it. Australia was discussed but nothing happened.[1] This might be useful if there were space stations that needed large, frequent deliveries of fuel, air, and water. [1] https://thespacebuc…
I have so many questions..! (And maybe the answers are somewhere on the page, but its navigational paradigm is too atrocious for me to handle) - how fast do you have to push something through the atmosphere to have it reach space? - and, how fast is the lever spinning to reach that velocity? how precise do you have to time the release? - after release, your lever is going to be pretty unbalanced. having seen what hap…
Okay so say 15.000 km/h, escape velocity + compensate for drag. At a 100 meter radius, that's a radial velocity of 41 radians per second (4100 meter/second) => 6.5 Hz spinning rate, or one full circle every 0.15 sec To hit the exit at an angle that's within 1 degree of target, that requires you to launch with 0.15/360=0.4 millisecond precision. Which seems... not entirely unhinged? Those 1000s of g-forces though...
Or maybe put a weight at the opposite end that moves towards the center as you release the payload, compensating for the lost weight at the other end? (* in terms of angular momentum)
Personally, I'd abandone 99% of all launches anyway. We just don't really need 12 different competing 15,000 satelite clusters to start with...
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Well actually.... Even if you place the exit at higher altitude with lower pressure, without a seal you'll still end up with higher pressure at the base. Just like you do in open air, the weight of the air column pushing down increases the pressure.
Good point! If the launch vehicle can accelerate well enough in low pressure instead of vacuum then maybe you could "just in time" depressurize segments of the tube. Although that's still getting perilously close to the magical airlock concept. Apologies for rambling, this is fascinating.
A many kilometers long linear accelerator that ramps off a suitable mountain could make for a interesting 1st stage that wouldn't subject the payload to ridiculous G forces. But you'd still need to accelerate the payload and 2nd stage and with SpaceX and co driving down 1st stage costs I still don't see it as cost effective.