11 points

It can also do laundry

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1 point

Get back to your workbench, dad. /s

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8 points

I heard about this and it’s a great idea if it works. It’s not totally fuel free as the throwing pay gets it mostly out of the atmosphere and there is a small rocket (last stage for a normal rocket) that puts the payload in the right place.

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11 points

It’s even far from fuel free, to reach Low Earth Orbit a rocket needs between 9.3 and 10km/s of delta-v.

According to the video the system is launching the rocket at mach 6, which is equivalent to 2km/s.

So the system is providing only 1/5 of the energy needed to get to orbit. It’s good but I’m not sure it is worth the drawback of having to handle the huge acceleration.

On the other hand the same system on the moon would provide enough energy to reach orbit, it would just need a small amount of propellant to circularize.

Or by increasing slightly the speed of the system it could even send stuff straight to earth with no propellant.

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20 points

20% of the delta-v is not the same as 20% of the energy or fuel. The early stage when the rocket is the heaviest and down in the thickest atmosphere is by far the most fuel-expensive.

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1 point
*

That actually makes it much worse. Kinetic energy is a square law so to reach orbit at 5 times the velocity requires 5x5=25 times the energy they’re currently using. And air resistance is also a square law so making it go 5 times faster also results in 25 times the air resistance and 25 times the heating due to it.

Most likely if they did get it going fast enough to make it to orbit, it’d burn up in the lower atmosphere before it even got very far.

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16 points

So, you want to build a trebuchet on the moon to throw rocks at Earth?

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7 points

Yes, who wouldn’t?

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1 point

Fuck yea

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7 points
*

The idea of throwing something into space isn’t anything new, tbh I’ve always kinda wondered why no one has spent more time developing it.

Edit: I wonder how many Gs the rocket experiences while spinning, and if a human could theoretically survive it long enough to get thrown into space. I can see it now: rockets becoming luxury space vehicles for rich people while the spin launch is how poor people commute to the space dock.

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11 points

The projectile experiences wicked g-forces when it is being spun up: around 10,000 times the force of gravity. This is enough to tear the skin and muscle off a human being. This means SpinLaunch will not be going into the astronaut business. They also won’t be able to drive large satellites into orbit. The projected weight limit for the system would be payloads of about 440 pounds. That is a lot less than something like the Hubble Space Telescope weighs. – source

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17 points

I mean, you would in fact get the astronaut into orbit, provided your container was water tight.

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4 points

Jesus fuck. I know humans can withstand extremely high g-forces for short periods of time, but 10,000 Gs is a lotta Gs.

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3 points

So… Wouldn’t a railgun system be able to do the same thing with less energy consumption?

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3 points

I think it would have to be crazy long up the side of a mountain or something to work. I always thought that would be cool to see. I’m just an ignorant layperson though. I know little of the actual science, but I have read a lot of science fiction in my life.

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3 points

…if a human could theoretically survive it long enough to get thrown into space.

The answer is ‘no’. This thing would spin all the blood out of your body, and then when it actually launches you, your body would get shattered by the shock, and then shattered again a millisecond later as your spacecraft plows into the atmosphere at a few mach number.

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5 points
4 points

Yeah I was gonna say…

No, no it doesn’t work.

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4 points

Usually when a SpinLaunch article or video is posted, all the armchair Physic PhDs show up pontificating on why it’s doomed to fail.

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13 points

Well it’s been almost ten years and they still aren’t launching into space so I’d say they’ve been correct so far.

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3 points

Everything is impossible, until it isn’t.

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3 points

Being possible and being feasible aren’t the same thing.

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1 point

And some things never are. I don’t think spin launch is doomed to failure, but there are definitely projects that some people take seriously that are legitimately never going to happen

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4 points

You’re dreaming of you think this is remotely feasible.

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1 point

Strange that a bunch of aerospace and mechanical engineers believe it is, and have tested the math, yet some random person who probably doesn’t even work on STEM believes they have the better idea.

I can’t tell if you genuinely think you’re smarter than these people or if this is just the classic “space craft are stupid!” Rhetoric that’s become popular since Musk started SpaceX.

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6 points

Strange that a bunch of aerospace and mechanical engineers believe it is

It’s not that strange. There are lots of people willing to con others out of investment money.

who probably doesn’t even work on STEM

You’re wrong there

I can’t tell if you genuinely think you’re smarter than these people or if this is just the classic “space craft are stupid!” Rhetoric that’s become popular since Musk started SpaceX.

I don’t think I’m smarter than these people. I think I’m smarter than the people being conned by these people. Spacecraft certainly aren’t stupid. A lot of what SpaceX has done in spite of Musk has been amazing to see. Their rocket engine development is some of the coolest stuff out there. It’s too bad that the company is led by a con man who makes grandiose claims that they’ll never live up to.

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1 point

You don’t need to be Stephen Hawkings to understand that the bottleneck is not in the launch sling but in the satellite themselves. The idea is in the same league as the space elevator; sure you can do it, but is it better than rockets?

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