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Can Spinlaunch Throw Rockets Into Space?


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I think that slow climbing is also better than fast one?

Air resistance grows like power or something (if I'm not mistaken)

From wiki:

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Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity.[4]

 

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14 minutes ago, vlaiv said:

I think that slow climbing is also better than fast one?

Air resistance grows like power or something (if I'm not mistaken)

From wiki:

 

Yes, I was reading something the other day about one of my other interests (motorcycle racing): the article said that when motorcycle racing got going seriously in the 1950s, they were recording top speeds of around 130mph with 60hp. Since then, engine power output in MotoGP has increased by 600-and-something percent, but top speeds have only increased by 60-ish percent (that's not to say that 220mph isn't plenty fast enough on 2 wheels!!)

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It does sound kind of ridiculous but surely there must be some potential or there wouldn't be any investment. I wonder if it could be an option for getting things off of planets with less gravity and/or thinner atmospheres such as the lunar surface?

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There are countless examples of serious money being outed into totally infeasible ideas…. It depends on how well you can convince people to put their money into. Some fail as they can’t run a business and some fail as the idea is undeliverable.

 

Peter

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The rocket is by far the best option, nice and slow when the air is thick then accelerating into a diminishing atmosphere however as a large proportion of the fuel is used getting it moving to a few hundred MPH then perhaps they need a gravity assisted  kick start similar to a roller coaster..

Alan

Edited by Alien 13
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1 hour ago, The Lazy Astronomer said:

Yes, I was reading something the other day about one of my other interests (motorcycle racing): the article said that when motorcycle racing got going seriously in the 1950s, they were recording top speeds of around 130mph with 60hp. Since then, engine power output in MotoGP has increased by 600-and-something percent, but top speeds have only increased by 60-ish percent (that's not to say that 220mph isn't plenty fast enough on 2 wheels!!)

All other things being equal, esp Reynolds number, air drag increases in proportion to the velocity squared. Since power = force x velocity, power required therefore increases in proportion to velocity cubed. The cube root of 6 is 1.82 so that seemingly modest increase in speed for a 6x increase in power is more or less as expected

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Anything coming out of the launcher tube will be a mist of atoms as soon as it hits the atmosphere at those speeds. This would be neat on the Moon though, if a base ever gets built. It could be orientated so that it gets put into Earth atmosphere intercepting orbit straight from the Moon with no propellant used. Not really usable for human transportation unless the centrifuge is absolutely massive in size to reduce G forces to crew, but if you wanted to move payload from the Moon surface to the Earth it would be pretty cool.

What would you want to shoot back to Earth though? Minerals? Rocks? Whatever someone figures out can be mined from the Moon for profit i guess.

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19 minutes ago, ONIKKINEN said:

Anything coming out of the launcher tube will be a mist of atoms as soon as it hits the atmosphere at those speeds. …

I too looked up earth’s escape velocity. Even without air resistance taken into account, it’s just over 11km/s!

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Gerald Bull managed to fire shells 155 miles into space, albeit not at orbital velocities, so it's pefectly feasible for an object to survive the journey through the atmosphere at a massive rate of knots.

There are designsfor shock absorbing systems that reduce the load on a payload to around 200 G for firing from an actual space gun, and it is possible to manufacture payloads that would survive that level of acceleration. 

The real issue is one of energy. Think of the energy that Bull's massive gun launcher brought to bear and that was insufficient to propel the Martlet 3 vehicle to an orbital velocity, so it seems inconceivable that a centrifuge could produce sufficient energy.  I'll have to do the maths, but even without reaching for the slide rule I can't see it happening.

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Orbital speeds wont be happening from atmospheric launches, whether it be from sea level or from the summit of Mt Everest. Or maybe they could, but it wouldn't be efficient and the satellite would still need to do a several km/s insertion burn at apogee. In an airless world you could point the launcher sideways and just a small correction would be required at apoapsis, but from an atmosphere you do want to launch at a fairly high angle, or the projectile will either burn up or slow down before escaping the atmosphere. The atmosphere acts like a soup made of brick walls at hypersonic speeds in the thick parts (below i dont know, maybe 30km?).

Launching at an angle of lets say 45 degrees could work, but then you would be going 45 degrees to the wrong way once in space, and you're actually probably only half way to orbital speed at apogee. If you just launched the projectile faster you would still be going the wrong way, but now faster and the apogee would be pushed higher, so still a problem.

Capture.PNG.7073980675f5effa0364561415e94361.PNG

If this is the projectile in question it would fit a decent sized mini-satellite that could have enough propellant of its own to reach orbit, but not sure if all this trouble is worth it to make sure the satellite can survive the G forces and all the design decisions that come with it.

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1 hour ago, Roy Cropper said:

Think of the energy that Bull's massive gun launcher brought to bear and that was insufficient to propel the Martlet 3 vehicle to an orbital velocity, so it seems inconceivable that a centrifuge could produce sufficient energy.

On the contrary, I think a centrifuge can impart more energy. It spins up over an hour, while all Bull's cannon could offer was a flash of cordite. He made the barrels longer so the projectile could benefit from a longer powder burn, but barrels can only get so long...

But... a malfunction in this machine would be apocalyptic!

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It's an interesting idea, but I have concerns about practicality when they scale up especially the hold and release mechanism and release timing. If they get these wrong the results could be messy

Scott Manley has produced a video about this too, and he raises a different set of questions.

 

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Hold on.

I just had an idea - what about massive fly wheel and rail gun?

With massive fly wheel we can build up and store great amount of energy slowly and (this is wild guess) - with super conducting coils we can extract that fairly quickly.

No rotation needed, smaller volume to produce vacuum in - less moving parts, but essentially the same concept. Dig few hundred meters of launch tunnel into the ground and use magnets for some crazy acceleration thing and there you go.

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20 hours ago, Alien 13 said:

The rocket is by far the best option, nice and slow when the air is thick then accelerating into a diminishing atmosphere however as a large proportion of the fuel is used getting it moving to a few hundred MPH then perhaps they need a gravity assisted  kick start similar to a roller coaster..

Alan

When Worlds Collide...

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