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SpinLaunch is building a centrifuge to launch satellites into orbit

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Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#61

Post by d_theorist »

TaylorAlexander wrote: post #56
blackrock wrote: post #50

Earlier quoted context omitted.

How is Starship going? Are they still trying to “sweat” the fuel out of the skin, to give it an active cooling layer?

Starship development continues apace. They’re planning to launch the latest starship vehicle to 50km altitude next week and then perform their difficult landing maneuver 15km from the launch site. I believe the sweating skin idea has been dropped. See this one hour video for a detailed breakdown of the current state of the design: https://youtu.be/-8p2JDTd13k

Next launch is 15km (not 50).

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#62

Post by piker »

Cthulhu_ wrote: post #58
blackrock wrote: post #49

Earlier quoted context omitted.

Raw metal powder for 3D printing laser sintering. Or plastic pellets. Water. Fuel. Clothes. Maybe this is what can kick start the 3D printing in space revolution. Maybe it can also launch radioactive waste into space? One bucket at a time. Then a space towtruck can be launched to hurl it into the sun. But it’ll likely just part a naive investor from their money.

Not sure how serious you are with the radioactive waste thing but I'll do the HN thing and bite (nerdsnipe!), because that's not going to work. You can't launch things into the sun, you need to decelerate objects. The earth travels at 30 km / s (70K MPH) around the sun, so you need to decelerate about that much the other way. And orbiting radioactive waste is just asking for trouble. The total amount of radioactive w…

> The total amount of radioactive waste on the earth is about the size of a swimming pool (or was that the total amount of gold? I forgot, either way in terms of quantity it's not that much)

This seems wrong in both places. There are probably enough gold rings manufactured per year to fill a swimming pool. In pictures: Fort Knox itself seems to have at least a swimming pool of gold [1] and Thailand a swimming pool of waste.[2]

[1] https://external-preview.redd.it/rgD0FO1pELgkuXZzWC2NQk0vJZU... [2] https://upload.wikimedia.org/wikipedia/commons/9/93/TINT_Rad...

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#64

Post by mlindner »

ogre_codes wrote: post #26

> At this point the spacecraft will be subjected to a peak force 10,000 times greater than Earth's gravity, something opponents believe will seriously affect its structural integrity and the safety of its complex electronics. These kind of forces are pretty insane compared to even the high G boost you get on a normal rocket launch. I wonder if that is going to put a crimp on their potential client list.

The forces are going even higher than that. 10,000g is what you get from launching out of high explosive powered military cannon. The US military has managed to put guided rounds in such cannons, but they certainly aren't getting you to space with such a cannon. You need much higher than 10,000g to get up to that kind of speed.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#65

Post by mlindner »

DennisP wrote: post #4

I hope it works because it'd be rad, but at $500K per 200-lb payload, they'll cost $2500/lb. That's only half as much as SpaceX Rideshare for the same size payload, today. If Starship works out, then SpaceX costs will drop enormously. Fuel is a minor portion of launch cost. SpinLaunch is saving fuel but throwing away rockets; it's going to be hard to compete with someone who throws away more fuel but saves the rocket…

No this won't work. The founders don't understand the physics involved and their estimates of the forces involved are wildly incorrect.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#66

Post by _Microft »

TaylorAlexander wrote: post #56
blackrock wrote: post #50

Earlier quoted context omitted.

How is Starship going? Are they still trying to “sweat” the fuel out of the skin, to give it an active cooling layer?

Starship development continues apace. They’re planning to launch the latest starship vehicle to 50km altitude next week and then perform their difficult landing maneuver 15km from the launch site. I believe the sweating skin idea has been dropped. See this one hour video for a detailed breakdown of the current state of the design: https://youtu.be/-8p2JDTd13k

It's being launched up to 15km, that's pretty close to 50000 feet, so you might have mixed up the units.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#67

Post by mlindner »

NikolaeVarius wrote: post #7
DennisP wrote: post #4

I hope it works because it'd be rad, but at $500K per 200-lb payload, they'll cost $2500/lb. That's only half as much as SpaceX Rideshare for the same size payload, today. If Starship works out, then SpaceX costs will drop enormously. Fuel is a minor portion of launch cost. SpinLaunch is saving fuel but throwing away rockets; it's going to be hard to compete with someone who throws away more fuel but saves the rocket…

Wut? Their goal is to allow the rocket to ignite at 200k ft. Thats only a bit lower than the altitude SpaceX ignites its second stage, which is not reusable

The problem isn't altitude, it's speed. Launching from the air has all the same problems of air launched rockets from planes. Except now they're trying to sling a massive rocket up to 200k feet along with all the sloshy liquids inside without anything breaking. It's complete and utter madness. The founders/investors are guaranteed to lose all their investments.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#68

Post by mlindner »

spicybright wrote: post #5
sneak wrote: post #2

How does this prevent the satellite from being damaged when it transitions from 5000mph in vacuum centrifuge to less-than-5000mph-in-troposphere 1 meter later just out of the door? That's gotta be one hell of a fairing.

Oh wow, I was wondering why bother building housing around it. That seems incredibly expensive to build and maintain. Your comment is very on point. If they slowly even out the atmosphere, they loose the speed. So they'll need to coordinate the door opening at exactly the right moment. And if it doesn't the whole instillation goes boom. I feel like it would be better just to use the money to buy more rocket fuel at t…

No they're definitely going to fail. The founders don't seem to understand how difficult this is. If you're going to build an accelerator you want it to accelerate over a very long distance and have it exit the vacuum well into the stratosphere if you can.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#69

Post by mlindner »

CGamesPlay wrote: post #17
beervirus wrote: post #3

“The reason it's hard to get to orbit isn't that space is high up. It's hard to get to orbit because you have to go so fast .” https://what-if.xkcd.com/58/ Sounds like this solves the easy part (getting to high altitude), but makes the hard part (getting to orbital velocity) even harder.

I think you're imagining that the rocket is fired directly vertically and peaks at some altitude, when the rocket ignite to "make it go fast". Instead, imagine the flings the rocket at a 45 degree angle so when it peaks in altitude it's already going quite fast. As other commentators in this thread point out, it's really an alternative for the primary stage rocket booster part, which doesn't just shoot a rocket strai…

Except they're completely inverting the rocket. The rocket goes slow in the lower atmosphere where the forces are lower. This allows them to lose much less energy in the lower atmosphere from drag.

If they could just launch at 45 degrees to get to orbit the rockets would do that too, but no they don't. They go straight up at first because the drag is such a huge penalty to the performance.

If they actually build this thing, the most efficient way to launch is to launch it almost straight up at 90 degrees so they lose the least energy. However the hardest part is going to be immediately after exiting this thing where they hit the atmosphere going mach 6-7 and instantly turn into a glowing ball of plasma, which is what happens if you try to move that fast at sea level.

Drag forces increase with the square of the velocity and linearly with fluid density. The instant it leaves the cannon it will feel like it's hitting a brick wall.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#70

Post by thombat »

mlindner wrote: post #67
NikolaeVarius wrote: post #7

Earlier quoted context omitted.

Wut? Their goal is to allow the rocket to ignite at 200k ft. Thats only a bit lower than the altitude SpaceX ignites its second stage, which is not reusable

The problem isn't altitude, it's speed. Launching from the air has all the same problems of air launched rockets from planes. Except now they're trying to sling a massive rocket up to 200k feet along with all the sloshy liquids inside without anything breaking. It's complete and utter madness. The founders/investors are guaranteed to lose all their investments.

Well somebody is sure to lose their money, but if enough bigger fools can be lured aboard it needn't be the current crew. In other words, the Nikola truck but in space.
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