Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Giant catapult sends satellites into space

spinlaunch.com

Post reply on HN
Print view View original

11–20 of 61 posts

Re: Giant catapult sends satellites into space

#11

Post by inexcf »

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.

Re: Giant catapult sends satellites into space

#12

Post by dang »

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)

Re: Giant catapult sends satellites into space

#13

Post by Manuel_D »

inexcf wrote: post #11

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 de…

The Excalibur 155mm artillery shell is supposedly subject to twice as much acceleration as the spin launcher, and it has a solid rocket motor. So it's probably possible. But solid rocket motors are less efficient than liquid fuel.

Re: Giant catapult sends satellites into space

#14

Post by isoprophlex »

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?

Re: Giant catapult sends satellites into space

#15

Post by patwolf »

readams wrote: post #7
kibwen wrote: post #5

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 de…

They'd be great for the Moon though.

Makes me think of "The Moon Is a Harsh Mistress", where the moon went to war with earth by catapulting rocks.

Re: Giant catapult sends satellites into space

#16

Post by vpribish »

Manuel_D wrote: post #8

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…

You got the basic physics, but don't you think they have considered these issues? It's why this is interesting at all : despite the very obvious difficulties they think this has a case.

Re: Giant catapult sends satellites into space

#17

Post by bloopernova »

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?

Re: Giant catapult sends satellites into space

#18

Post by londons_explore »

Manuel_D wrote: post #8

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…

> spin launch is going to have to withstand both lateral and vertical Gs.

I wonder if there is a trick to rotate the craft between disconnection and hitting the atmosphere so that the forces are in the same direction for both?

Re: Giant catapult sends satellites into space

#19

Post by ARandomerDude »

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.

Re: Giant catapult sends satellites into space

#20

Post by rendall »

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

Post reply on HN