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 released, so it's going to bleed off a lot of speed before it reaches the upper atmosphere.

Second, spinning exerts very heavy lateral Gs on the vehicle and load. This is not typical for space launch payloads, which are usually only designed to withstand vertical Gs. When the catapult releases the payload, atmospheric drag is going to put heavy vertical Gs on the payload. So a payload delivered through spin launch is going to have to withstand both lateral and vertical Gs.

Its an interesting concept, but I'm not sure if the advantages of this approach outweigh the disadvantages.

I do see a future use case for spin launchers based in vacuum, say, on the moon. Or maybe on Mars where atmosphere is much thinner.

Orbital accelerators are cool, IMO they feel much more sci-fi than rockets (and still a step below space elevators). They're not without their tradeoffs, though: the G-forces involved mean they're not suitable for living creatures, and because of atmospheric drag they're most suited to putting things into lower orbits.

https://en.wikipedia.org/wiki/Space_gun

"In Project HARP, a 1960s joint United States and Canada defence project, a U.S. Navy 410 mm (16 in) 100 caliber gun was used to fire a 180 kg (400 lb) projectile at 3,600 m/s (12,960 km/h; 8,050 mph), reaching an apogee of 180 km (110 mi), hence performing a suborbital spaceflight."

I remember this being a horrible idea for many reasons.

One reason being the speed needed at the start which probably meant most loads burning up in the thick atmosphere immediately.

Another reason being that if you would use it to start a rocket which will only use the spin launch as a booster replacement, you would run into the problem of the fuel being pressed towards the front of the rocket as it is constantly decelerating after the launch. So you would probably need a system to actively move the fuel down to the nozzle.

As I said here a few years ago, I support this sort of company. VCs are basically stupid, especially for companies that are more complicated than gluing javascript together, and so it’s only just and right that some actual engineers have some fun in the desert for a few years at their expense, and get some experience putting ambitious, if ultimately silly, machines and prototypes together quickly and scrappily for a few years. Then when spinlaunch goes bust, which of course it will as its idea makes zero sense from an engineering pov, there will be a bunch of hardened and experienced engineers who can go and work for people with more of a clue and do something useful. It’s like a well funded extra-curricular student project.

Accelerating in a huge vacuum chamber seems pretty difficult to achieve, and wouldn't there be a huge shock to the vehicle as it hits a wall of dense air?

How much of a difference would a low pressure chamber make, I wonder? Maybe you could build the circular accelerator then a much longer exit pipe that runs up the side of a mountain. Although that sounds way, way easier said than done! But if your exit air pressure is roughly equal to your accelerator air pressure, then you don't need a fancy airlock system.

The tether they proposed also seems a bit too much of the wishful thinking like "we just need a bundle of carbon nanotubes 1km long!" Wouldn't an electromagnetic accelerator work better?

Metaculus has this at 4% that it will launch anything to low earth orbit by 2032.

https://www.metaculus.com/questions/12245/spinlaunch-payload...

According to The Space Bucket youtube channel, there has been no update to the company's progress since 2022, and there was a shake up in the top leadership. It looks like this project is likely dead in the water.

https://youtu.be/kGxmCvLb9bs

This has appeared a few times, and the basic physics critiques haven't changed.

It's one of those projects where it would thrill my inner sci-fi nerd to see it succeed... but not enough for me to disregard the reasons it probably won't.

The recent news items about them have the "someone please buy us" desperation vibe to them. It was an exciting startup 10 years ago or so, then everything went quiet, then all of the sudden there were some items in the news but nothing really substantial - "we hit orbit" or something like that. Just a nebulous "Oh, there Spinlaunch, remember us?"

There seem to be a lot of businesses like this one: well-funded by VC money, but trying to do things that are scientifically questionable. This reminds me a bit of Helion Fusion, which is supposed to produce commercial power by (I think) 2029? Something seems a bit wrong with our VC markets if stuff like this is getting funded.

So, we're back to the space elevator as the only means to prevent burning a bunch of shit for every launch?

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...

Reminds me a bit of the launch system in When Worlds Collide (1951). (A giant roller coaster track, essentially.)

https://www.youtube.com/watch?v=avtQ8elxL-o

I could imagine commercials, in movies they have this bow and arrow guy the arrow shoots towards the viewer then the logo appears

Here it's a baseball pitcher or that spinning throw (not discuss, they use a ball) then it says "Spin Launch"

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

Related. Others?

SpinLaunch: Giant catapult launching satellites - https://news.ycombinator.com/item?id=41925019 - Oct 2024 (53 comments)

Company wants to 'throw' rockets into low orbit to save fuel - https://news.ycombinator.com/item?id=41768182 - Oct 2024 (3 comments)

Giant catapult defies gravity by launching satellites into orbit - https://news.ycombinator.com/item?id=41919846 - Oct 2024 (3 comments)

Rocket company develops catapult to launch satellites into space - https://news.ycombinator.com/item?id=40731585 - June 2024 (2 comments)

Will physics prevent SpinLaunch from succeeding? - https://news.ycombinator.com/item?id=33687266 - Nov 2022 (1 comment)

SpinLaunch just catapulted a NASA payload into the sky for the first time - https://news.ycombinator.com/item?id=33112413 - Oct 2022 (10 comments)

NASA Tests Gigantic Slingshot for Hurling Objects into Space - https://news.ycombinator.com/item?id=33088860 - Oct 2022 (6 comments)

Can We Throw Satellites to Space? – SpinLaunch - https://news.ycombinator.com/item?id=32375464 - Aug 2022 (5 comments)

An Inside Look: SpinLaunch Flight Test #7 - https://news.ycombinator.com/item?id=31098021 - April 2022 (4 comments)

NASA will test SpinLaunch's ability to fling satellites into orbit - https://news.ycombinator.com/item?id=30996665 - April 2022 (200 comments)

Alternative rocket builder SpinLaunch completes first test flight - https://news.ycombinator.com/item?id=29658592 - Dec 2021 (1 comment)

Spinlaunch: Busted - https://news.ycombinator.com/item?id=29578792 - Dec 2021 (1 comment)

Scientists find a way to ‘catapult’ rockets into space like ‘slingshots’ - https://news.ycombinator.com/item?id=29432727 - Dec 2021 (50 comments)

SpinLaunch completes first test flight with rocket-flinging launch system - https://news.ycombinator.com/item?id=29198589 - Nov 2021 (219 comments)

Spinlaunch with Basic Physics [pdf] - https://news.ycombinator.com/item?id=29183158 - Nov 2021 (2 comments)

Spinlaunch completes suborbital launch without engine - https://news.ycombinator.com/item?id=29175912 - Nov 2021 (6 comments)

SpinLaunch is building a centrifuge to launch satellites into orbit - https://news.ycombinator.com/item?id=25204660 - Nov 2020 (143 comments)

SpinLaunch raises $40M to build a machine to catapult objects into space - https://news.ycombinator.com/item?id=17317688 - June 2018 (105 comments)

Space catapult startup SpinLaunch comes out of stealth - https://news.ycombinator.com/item?id=16439835 - Feb 2018 (110 comments)

Much as I might like to see alternate ways of launching succeed, I have always thought that physics was not on their side.

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 happens to an unbalanced ultracentrifuge in a lab (spinning a few grams of biological samples), how does this thing launch a 100kg satellite without wrecking the launch station?

- does this mean all the remaining angular momentum is in an opposite weight you discard simultaneously by slamming it into the ground? do you just sling the payload around in some ridiculously unbalanced manner?

- can you launch things with liquids (eg., fuel) at all due to crazy sloshing mechanics?

Does it though...

Somehow it’s hard to believe that the lower dense part of the atmosphere doesn’t slow it down or even burn it. It happens when these things fall down… why not when going up?