The Lemon Fool

How can you launch a satellite into orbit without most of that heavy mostly-fuel rocketry stuff?

You chuck it into orbit!

More precisely, SpinLaunch puts the satellite plus a small rocket into a dart, which they attach to the end of a 100m arm and spin up (in a vacuum) to 10,000g, and fling the dart out and up at 5,000mph. Once clear of the atmosphere the small rocket takes over to get the satellite into its correct position. Launch cost $0.5m vs typical $7m.

https://www.bbc.co.uk/iplayer/episode/m00142dw/click-swingin-satellites (first 7 minutes or so)
https://www.spinlaunch.com/ (I hope their accelerator tech is as good as their ability to make glossy videos!)

The obvious drawback is the satellite and all its gizzards needs to be structurally strong enough to withstand the centrifugal force developing on it while it spins up to launch speed.

The accelerations during conventional rocket launch are much gentler, I would imagine.

Sounds like something from Victorian times (or Wallace and Gromit). Just lacking a steam engine.

Must be interesting designing a satellite which can withstand those enormous g-forces.

--kiloran

https://www.thiot-ingenierie.com/en/201 ... 00000-g-2/

"CHRONOS will make it possible to test the behaviour of the electronics during these extreme acceleration and deceleration phases, in which the forces can reach 100,000 g. "

kiloran wrote:
Must be interesting designing a satellite which can withstand those enormous g-forces.

--kiloran

True. WW2 artillery proximity shells had to withstand huge g forces using vacuum tubes. Some anti-aircraft fuzes had to withstand up to 20 000g. In addition to extreme acceleration, artillery shells were spun by the rifling of the gun barrels to close to 30,000 rpm. State of the art war-winning technology of its time.

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

RC

kiloran wrote:Sounds like something from Victorian times (or Wallace and Gromit). Just lacking a steam engine.

Well actually, in Jules Verne's 1865 novel From the Earth to the Moon he had a somewhat similar idea of "shooting" a projectile into space, in his case doing so from a giant cannon and with the projectile carrying three people to the moon. As Wikipedia notes, "his scenario turned out to be impractical for safe human space travel since a much longer barrel would have been required to reach escape velocity while limiting acceleration to survivable limits for the passengers.".

However, it seems a space gun (aka a Verne gun) was developed by the joint US-Canada Project HARP (High Altitude Research Project) in the 1960s, which according to the founder of SpinLaunch* inspired them to explore kinetic energy launch systems. In 1966 the 16-inch HARP gun fired an 84kg projectile to a height of 180km (a record that still stands) so achieving a suborbital spaceflight.

* https://www.spinlaunch.com/gallery, "Intro To Spinlaunch" video. Includes some film of Project HARP.

mc2fool wrote:How can you launch a satellite into orbit without most of that heavy mostly-fuel rocketry stuff?

You chuck it into orbit!

More precisely, SpinLaunch puts the satellite plus a small rocket into a dart, which they attach to the end of a 100m arm and spin up (in a vacuum) to 10,000g, and fling the dart out and up at 5,000mph. Once clear of the atmosphere the small rocket takes over to get the satellite into its correct position. Launch cost $0.5m vs typical $7m.

https://www.bbc.co.uk/iplayer/episode/m00142dw/click-swingin-satellites (first 7 minutes or so)
https://www.spinlaunch.com/ (I hope their accelerator tech is as good as their ability to make glossy videos!)

I think I read about this a few months ago. I've worked in labs where we used ultra-centrifuges and after remembering stories from our old Biology teacher, was always a little nervous. The kinetic energy in those things is just incredible! According to our teacher, when he was at uni, ultra-centrifuges were only used in basements for safety reasons. He told a story about one centrifuge in a lab that broke, sending the samples through several solid walls and down the road.

Steve

PS On checking, I just realised that the Spin Launch isn't nearly as fast as an ultra-centrifuge, in fact 10,000g is quite low, but then I guess that the payload is a lot heavier than the plastic sample tubes we used.