SoylentNews is people
SoylentNews
Startup SpinLaunch Inc. has received $40 million in funding. The company intends to use a centrifuge to catapult small payloads to the edge of space:
The company remains tight-lipped about exactly how this contraption will work, although its name gives away the basic idea. Rather than using propellants like kerosene and liquid oxygen to ignite a fire under a rocket, SpinLaunch plans to get a rocket spinning in a circle at up to 5,000 miles per hour and then let it go—more or less throwing the rocket to the edge of space, at which point it can light up and deliver objects like satellites into orbit.
[...] Over the past few years, the rocket industry has become quite crowded. Following in the footsteps of Elon Musk's Space Exploration Technologies Corp., dozens of companies have appeared, trying to make small, cheap rockets that can be launched every week or perhaps even every day. These smaller rockets have been built to carry a new breed of shoebox-sized satellites—dubbed smallsats—that are packed full of imaging, telecommunications and scientific equipment. The small rockets, though, are really just miniaturized versions of the large, traditional rockets that have flown for decades. SpinLaunch is an entirely new take on the rocket-launch concept itself.
[...] SpinLaunch has a working prototype of its launcher, although the company has declined to provide details on exactly how the machine operates or will compare to its final system. The startup plans to begin launching by 2022. It will charge less than $500,000 per launch and be able to send up multiple rockets per day. The world's top rocket companies usually launch about once a month, and most of SpinLaunch's rivals have been aiming for $2 million to $10 million per launch for small rockets. If the startup were able to reach its goals, it would easily be the cheapest and most prolific small launcher on the market.
NextBigFuture puts the velocity at up to 4,800 km/h (3,000 mph) instead.
(Score: 2) by choose another one on Sunday June 17 2018, @03:44PM
> Did I make reasonable assumptions? Did I run the numbers correctly?
Suspect you are in the right ballpark - in particular the g force is in the range I've seen quoted elsewhere for this type of system.
I reckon your aiming window is probably too small though - even at hypersonic speeds variable atmospheric conditions will probably give you more error than that over 100km, and if you assume a second stage rocket you can make adjustments with that burn.
Holding, and releasing, 100 tonnes is not a massive problem - a big jet engine is half that in thrust, or take a look at the Saturn 5 hold down systems or the pyrotechnic nuts that held the shuttle on the pad (against 1million pounds or so of SSME thrust - they wouldn't hold once the SRBs lit, but weren't designed to).
Releasing with microsecond timing might be, but I suspect (see above on aiming window) it might only need millisecond, and pyros (explosive bolts etc.) can do that, I think. You might even be able to get away with last century mostly mechanical stuff, I seem to remember (although this is memory from decades ago) that with ejector seats once the initial squib went off everything was timed and triggered, sometimes mechanically, by how far up the rail the seat was, and those sequences were timed to the millisecond [you'd better hope they are accurate or you'll be punching a hole in the canopy with your head (or similar) which doesn't usually end well].
The bigger problem is the g force, which I am pretty sure is in the right ballpark. Designing payload for 10g (which is some margin over eg. Falcon 9 max) is going to be an awful lot different to designing for 10,000g. There is a reason centrifuges are used to separate payloads into component parts. While I am sure it _could_ be done, I am not at all sure it could be done without increasing payload mass (and/or cost), a lot. Payload mass is of course what you are paying to launch. Not real sure of the benefits of designing a cheap (per/kg) launch system that requires payloads to be much heavier / more expensive.