Orbital launch rail guns

yea this seems silly. i was only imagining shooting stuff from a high mountain in ecuador.

It's just R=exp(dV/Ve)
Space shuttle main engines have a specific impulse of 453 seconds in vacuum. 4440 meters/sec.
Required dV (including drag and gravity losses) is about 9400 meters/sec. R =8.31
Reducing that by, say, 20% means the accelerator has to supply 990 meters/sec.
If limited to 4 gee, the track has to be 12.5 km long.
Something that long has to be straight and nearly horizontal, so you'd lose some of the gain to increased drag in the lower atmosphere.

The POINT is that you don't go fast at low altitude because "max Q" will destroy your vehicle and you waste more & more to air drag

Cost, reasons and capabilities to be in space that will pay for the silly sized investment, and the development of the technology, but i guess hyperloop is a step in that direction. Once the technology is ready to harvest asteroids worth hundreds of trillions it won't take long. There is also ion thrusters removing need for propellant or massive structures but they aren't quite there yet.

>>While NASA has no plans to bring the massive asteroid home and lacks the technology to mine it, Elkins-Tanton calculates that the iron in 16 Psyche would be worth $10,000 quadrillion, Global News reported. That's right, $10,000 quadrillion, as in 15 more zeros.

Goodbye economy as we know it

>thats what energy storage is for
user, if you had a solution for high efficiency, practical energy storage on this scale, you would solve the global energy crisis overnight.

The coolest thing about asteroid harvesting is that you can just use the asteroid as propellant. All you need is absurd amounts of energy and / or time.

user, the accelerator doesn't need to operate all the

Hrmm...but why space when speed of light won't cut it?

Why space mine when you can make any element out of hygrogen?...first make hologram, then comes holodeck/replicator. Stack photons using filters.

Silly simple.

rail-assisted-balloon-assisted-eco-friendly-self-driving rockets

Supply and demand. Diminishing returns.
If you owned a copy of Action Comics #1 it'd be worth millions.
If someone found a cache of 50,000 copies they'd be five bucks apiece plus shipping on eBay.

user what the fucking fuck are you even talking about.

altitude really doesn't matter much. most of the dV you need to reach orbit is horizontal. it's piss easy to send a rocket straight up into space; getting it to stay there in orbit is the hard part

so you just sit on supply and dole it out piecemeal. that's how the diamond industry has survived, by artificially restricting supply

Also jews brainwashing people into thinking diamonds have any value

>- Can't accelerate at more than 4G if you don't want to kill everyone in it.
Humans can take a lot more than 4 g. Fighter pilots take at least 8 g in hard turns without passing out, even more if just for a short period.

and they burn that delta-v after they are above the thick lower atmosphere
Even the tallest mountain is well within that
You don't go fucking hypersonic at 15,000 feet you will destroy your craft

I think you'd need more than "cables" to keep that up.

Yeah, the centrifugal force provided by magnetically levtitated projectiles going back and forth in the tube keeps it up

youtube.com/watch?v=J1MAg0UAAHg

More people need to know about launch loops.

Except from that iron has a very practical use while old comics just sit on shelves.

thats not even have physics works

Not the poster of but the concept is sound.
What you can't see is a ribbon of iron thrown into the sky. It arcs between stations on the ground. The trajectory it follows is an ellipse, the orbit any free body would trace if gravity was somewhat higher than actual. The "excess gravity" is because it's supporting a non-moving structure connected to stabilizing guy wires. When it reaches ground again it passes around a curve and is cast back towards the other terminal. The reaction forces of the turnaround are taken up by the ground.
It would work without requiring incredibly strong materials. But it would have to be absolutely reliable. If the ribbon ever stopped moving, it would all collapse back to the ground.
The lower sections, where it's inside the atmosphere have to be inside shielded tubes. A space craft would be lifted past those sections and then it would "grab" the ribbon and be accelerated to orbital velocity and beyond. Incoming craft could latch on and bleed their excess kinetic energy into the ribbon. Like a tethered "skyhook" energy is required only to make up for losses.

Since Psyche quite possibly is the core of a broken planetesimal, it might also be very rich in rare metals like the platinum group and rare earth metals. Mining it will simply and brutally tank the Chinese hold on this market and much of Africa will see their raw material trade implode overnight.

Because in order to not destroy any payload that's not an artillery she'll it would have to be so long that'd be the single largest structure made by humans ever. We can't even get our shit together long enough to pass a budget under a deadline. Maybe the Chinese will build it.

*shell

you can't get a rocket into orbit with a single burn from sea level, you need to ascend through the atmosphere and fire horizontally to get into orbit, a mass driver cannot get things into a circular orbit, maybe a highly elliptical one at best.

humans can withstand 40+ Gs horzitonally for small amounts of time and 20+ Gs for minutes

Seems legit

That's not a real issue though, use your BFG to fire up at an angle, then a relatively small amount of onboard fuel to bend it to an orbit.

Or don;t go into LEO at al -- BANG! ZOOM! Right to the moon!

Im no bio fag but what about selfrepairing metalls ?

A ship could have like 10 off them in store and switch them every 1-4 shots, and wait will they "healed" them self

>selfrepairing metalls
Why not the t1000? Self repairing metals are science fiction. In the micro scale it works sometimes but macro level self repair is physically impossible.

>What you can't see is a ribbon of iron thrown into the sky. It arcs between stations on the ground.
This is also science fiction.

it works like self-siphoning beads, but a complete loop with a motor to keep the loop moving at speed
then the sled grabs onto the loop as it's going and lets go at the top
when you turn the motor off (gradually) the whole thing settles back down onto the ocean, and vice versa

it would be really hard to build, but the physics are all sound

youtube.com/watch?v=jgz9CN2EBBY

>Every physics toy/trick is infinitely scalable.

youtube.com/watch?v=rffAjZPmkuU

Waiting for the day when one breaks in operation sending a wire hurtling through the outer atmosphere to land who knows where.

why dont just make diamond rocket?

cant break and go very fast to space becuase tkes off from strong start

this is not the physical effect that is intended for that meme cable supports itself thing
Thats just the beads backing up and pushing themselves up

No you can't build something thousands of miles along that suspends itself

How you protecc from space thieves who want diamond?

>enclose with vacuum tunnel
Easier said than done. How are you going to stop air getting in but allow the payload to get out?

>only 2 viable ways to explore space
>giant missiles
>giant guns

I guess when all you have are hammers, everything starts looking like nails....

As long as the power is on, the structure stays up. The vacuum sheathes extend to orbital altitude. They don't need to be closed at the end. Gravity keeps the air molecules from going that high. The moving ribbon just shoots out the end. It bends more nearly horizontally at that point because of the weight of the non-moving structure and the tug of the stabilizing cables.

Imagine a loop circling the equator 100 miles up and moving at orbital velocity. Each bit of it is a satellite. It doesn't fall and it's under no tension. If the loop spins faster than orbital velocity, it will come apart unless;
1 The loop has sufficient tensile strength, or
2. Some force compresses the ring, forcing each segment towards the Earth, countering the excessive centrifugal "lift".
The weight of the non-moving structure provides that compression. In turn, the ribbon supports the non-moving components.

A launch loop is, is essence, a segment of that world-girdling ring. Instead of going all the way around, it doubles back on itself. The reversal exerts a reaction force on the base stations. The ground in between the base points is in tension, but I think the crust of the Earth can stand a few extra kilotons of force.

No one denies that building a loop would be a terrific engineering challenge. It's marginal with current technology. But no new principles are involved and super-strong materials aren't required. What would a Roman engineer, building aqueducts of stone arches have thought of the Golden Gate Bridge? If you have adequate materials, size alone is not an objection to any project.

The chief obstacle is economics. The loop can throw a great deal of material into orbit. But, like a mass-transit system, it's only worthwhile if it's used at near capacity. Do we need to orbit so much stuff? Will there be a market?

The top won't reach outside the atmosphere, just into very thin atmosphere. Some air will still flow over into the open end of the pipe and begin filling up the bottom until the internal pressure equals the external pressure, perhaps with a slightly different atmospheric composition. To prevent this you'd need to continually pump air out of the bottom, and maybe keep the end closed until you shoot the thing also. I'm not sure what scale the air you'll be pumping out will be, but I think 100Pa to 10Pa is a good start for the pressure, as is 5m for the tube radius. Any fluid dynamicists want to run the numbers?

How do you orbit the loop?

You can't keep the end closed between shots.
The ribbon has to run continuously.

But the leakage rate (which has to be continually pumped out) might be quite small. Cross-section of the opening times air density at altitude (remember, we're high enough that objects released at orbital speeds will stay in orbit for at least days or weeks) times the speed of sound. "Properties of atmosphere" tables don't go above about 30 km, at which point density is about .003 kg/m3. A reasonable approximation at that point might be a decrease by a factor of "e" with every additional scale-height (about 8 km). At 100 km, density would be (very) roughly 5e-7 kg/m3. If the opening was 10 m2 (wild overestimate) and speed of sound 1000 m/sec then the pumps have to deal with 5e-3 kg/sec. Not significant.

For further technical details, including how to get the thing started in the first place, see
en.wikipedia.org/wiki/Launch_loop

>why space when speed of light won't cut it
Only if you're a pussy with the attention span of a goldfish. Just because you can't buzz around the galaxy instantly doesn't mean you can't colonize it and traverse it using well understood physics.

If life extension gets anywhere, even the light lag problem solves itself.
Active support structures are not science fiction at all. It's just firehose levitation with particle accelerators.

You don't orbit it, you shoot a fuckload of mass through at above orbital velocity, and contain it with magnetic fields. the mass wants to keep moving outwards and up, but your structure is providing centripetal force and containing it.

>and contain it with magnetic fields
really? how do you get the magnetic fields up there?

loops of [super]conductive material

>> particle accelerators
More like heavy artillery coilguns

You got the wrong idea, then.

>Active support structures are not science fiction at all.
Ok Show me a picture of a single building that keeps itself up by shooting water or particles or metal ribbons.

Elon Musk did
he's like real life Tony Stark
I fucking love that dude

real design proposals != science fiction

The launch loop as well as its logical extension - the orbital ring - WOULD work, they would just be insanely expensive and probably quite difficult to pass through the red tape.

So it keeps itself up with it's own magnetic field?

Are you aware of what science fiction actually means?

No, it keeps itself up by expending energy to accelerate thousands or millions of tons of matter above orbital velocity, and keeping it contained. You could make it work with hotwheels cars if they could withstand the mechanical stresses.

For the purposes of this discussion as according to you, something that ain't gonna work. Don't pull the semantic bullshit. Might as well say concept cars or next year's iPhones are science fiction because they haven't been built yet and maybe never will be.

You tried to dismiss it as bullshit, I showed you it could work with highschool physics. Suck my dick.

>Dyson spheres are totally going to happen.
You really are stupid.

are you dyslexic?

Gerald Bull did some interesting tests regarding the possibility of using cannons to get objects into orbit. However, the US government shut his project (HARP) down and he had to move his operations to Iraq. Unfortunately, ((they)) (and I don't use (()) jokingly, it was literally Mossad who carried out the assassination) killed him.

What do you think holds up buildings like this?
Particles (individual molecules) bouncing off the undersurface of the roof!
It's actively supported. Without the compressor, the whole thing collapses.

It keeps itself up, ultimately, by reaction against the ground.

The point is you're moving quite a bit more mass at a much lower speed than a particle accelerator. The navy's battleship railguns are heavy artillery and fire 3 kg projectiles at 2.4 km/s. The launch loop rotor consists of a bunch of interlocking iron rotors with about 3 kg/m density, moving at 14 km/s. This can be seen as a stream of continuous heavy artillery fire.

Really its a fun analogy more than anything else.
How do you get the loops up and the loop of cable up? Can you show that the system is stable?

Also why the fuck is there only like one paper on the launch loop? Where the fuck are the studies on the dynamics of the launch loop? Where are the numerical simulations of the launch loop responding to transient loading?

>How do you get the loops up and the loop of cable up? Can you show that the system is stable?
>Also why the fuck is there only like one paper on the launch loop? Where the fuck are the studies on the dynamics of the launch loop? Where are the numerical simulations of the launch loop responding to transient loading?
I don't know. Probably because the orbital ring is much cooler. As for the raising it up, you do it by starting the rotor and slowly raising it.

The Wikipedia article en.wikipedia.org/wiki/Launch_loop
references several papers on its theoretical stability.

EVERYONE JUST FUCKING READ THESE PAPERS BEFORE POSTING MORE BRAINLET SHIT!!!!!!!!
orionsarm.com/fm_store/OrbitalRings-I.pdf
orionsarm.com/fm_store/OrbitalRings-II.pdf
orionsarm.com/fm_store/OrbitalRings-III.pdf
slides.launchloop.com//launchloop.pdf
launchloop.com/LaunchLoop?action=AttachFile&do=view&target=isdc2002loop.pdf
spacecable.org.uk/Stability IAC.pdf

>Welcome to Orion's Arm, a scenario set thousands of years in the future where civilization spans the stars. Godlike ascended intelligences rule vast interstellar empires, and lesser factions seek to carve out their own dominions through intrigue and conquest. Out beyond the edge of civilized space and the human-friendly worlds, adventure awaits those prepared to risk all.
In other words Science Fiction.

I'd read that sci fi.

I bet your bar-mitzvah was an embarrassing affair

As some other guy said a long rail gun would be needed, and efficiency of the rail gun decreases fast with it's length

Thanks for posting the links.
The sarcasm of brought memories of ads for a tabletop game. (This was pre-internet.)
Relief to find serious engineering calculations by the BIS and others.

The problem is you only have an initial force against constant friction.
You need a craft and materials that can take the full force of a rocket launch in the second it launches off of the ramp.
Meaning at launch, a payload would have to have thousands of times more force/acceleration than a rocket AND survive the frictional force of the atmosphere.
Not plausible on earth.

From the launch loop wikipedia:
>>an additional instability is present in that the cable/sheath/rotor may undergo meanderingmodes (similar to aLariat chain) that grow in amplitude without limit.
>>Lofstrom believes that this instability also can be controlled in real time by servo mechanisms, although this has never been attempted.
Let's repeat the key points here
>>THAT MAY GROW IN AMPLITUDE WITHOUT LIMIT
>>CONTROL HAS NEVER BEEN ATTEMPTED

So the launch loop has an instability that has not been addressed. Also the one single launch loop paper and presentation does not address this, nor many of the issues I raised. And I am only discussing the launch loop not orbital rings or the space cable

Maybe it's fatally flawed and maybe it's not.
Won't know until someone does a detailed analysis and/or performs some experiments.

No one is doing either. No one's willing to pay for it.
A launch loop is useless as a weapon. Too big and too fragile and it can't be "aimed" at multiple targets.
So there's no military incentive.
And it's only worthwhile if you're launching a LOT of stuff. No one is. Rockets are profitable and sufficient to meet current demand.
So there's no commercial incentive either.

so at the very least it seems the space cable has addressed some of the stability issues.

>If a major failure did occur the energy in the loop (1.5×1015 joules or 1.5 petajoules) would be approaching the same total energy release as a nuclear bomb explosion (350 kilotons of TNT equivalent), although not emitting nuclear radiation.

>5e-3 kg/sec
Wow thanks.

What if we used a railgun system to launch a SCRAM jet shuttle?

See, the SCRAM jet does the lions share of the work getting the payload to mach 25-ish and on a ballistic sub-orbital arc. Then it stages and glides back to Earth. The Second stage is just a conventional rocket but it just needs to get the periapsis up from Lithobraking altitude.

Spread across maybe 2000 km. As soon as the ribbon fell into atmosphere it would vaporize harmlessly. Wouldn't be like an atom bomb falling on a city.

Using it to get a scramjet started would work. But so would JATO units or turbojets which dropped off and glided back to base.
A working scramjet booster would very likely lower the cost of getting to LEO. So far though, the record engine operating times is 5 seconds, to the best of my knowledge.

This is not true.

>What if we used a railgun system to launch a SCRAM jet shuttle?
Thrust to weight ratio of 2 : 1.

Correct. is pulling numbers out of his ass.
John Stapp braked from 632 MPH at 46 gee -- but it only lasted six tenths of a second.
Correlates well with this curve I found.

What if the failure happens at the point of greatest stress, on either of the two ground loops?

The same thing that happens when a rocket fails at ground level. A lot of energy released in an uncontrolled manner.

This thing would likely be set up at sea, so I image you would probably design the thing to use the ocean as the mother of all energy sinks in such a case.

And it would still release only a tiny fraction of its KE at those points.

Except that this is 100 times the energy of the Saturn V rocket.

hahahahaha you are a fucking idiot

>Implying we haven't already observed one in the process of being built across the galaxy.

The whole first half of this statement is wrong af

>- Can't do a circular either track because centripetal forces killing everyone inside again
Hahahahahahahaha How The Fuck Is Centripetal Force Real Hahahaha Nigga Just Rotate The Chairs Like Nigga Align Your Back With The Acceleration Vector Haha

That would be news to me. When did we observe that?