Slingatron vision is to launch payloads into orbit

Jul 25, 2013 by Nancy Owano report
An artist's concept for a full scale Slingatron space launcher about 200-300 meters in diameter. The spiral track is mounted on support pylons which contain drive motors and counterweight flywheels. Payload assemblies are prepared for launch nearby.

A Kickstarter project features Slingatron, the work of a seasoned team of scientists as a way to put cargo into orbit. The Slingatron is a mechanical, hypervelocity mass accelerator. The inventor of the Slingatron is Dr. Derek A. Tidman, author of the book, "SLINGATRON - A Mechanical Hypervelocity Mass Accelerator." The book sets forth the concept and now Hyper V Technologies of Chantilly, Virginia, the project leaders, are to put the Tidman concept into action.

Tidman is part of the Hyper V Technologies team presenting the Kickstarter project. According to his biographical notes, he first came to the U.S. as an assistant professor at the Fermi Institute for Nuclear Studies, University of Chicago. In reviewing the book, Daniel Spicer, senior scientist, Emeritus, NASA Goddard Space Flight Center, commented that "the Slingatron is a highly imaginative and surprisingly simple approach to accelerate large masses to using just off-the-shelf technology and good old-fashioned classical Newtonian mechanics."

A generous display of descriptions on how it works is on the Kickstarter page. The Slingatron technology can be incrementally grown in performance and size to payloads into orbit. The Kickstarter project goal is to build and demonstrate a modular Slingatron to launch, in the team's laboratory, a 1/4 pound payload to 1 kilometer/sec. That is about 2,237 mph. If launched straight up at that speed, a payload would reach an altitude of about 51 km, neglecting air resistance, they said.

They have turned to Kickstarter for the next step in making Slingatron a reality and that next stage will give them technical information, practical experience, and cost data on what will be required to build a full-scale Slingatron orbital in the future. They said they plan to use Kickstarter funds to build a modular, horizontal Slingatron device that is five meters (16.4 feet) in diameter and capable of gyrating at 40 to 60 cycles per second (cps).

"This Slingatron will be designed to be able to launch a 0.454 kg (1 lb) payload at a velocity of one kilometer per second, but will only be operated with 1/4 lb payloads for the demo. It will take us approximately six months to build and test the demo device."

The project will only be funded if at least $250,000 is pledged by Aug 22. They are inviting pledges from one dollar to $10,000 and above. At the time of this writing they raised $4,842 with 28 days to go.

HyperV Technologies is focused on producing "the world's first commercially viable fusion reactor technology." Their research efforts are on the development of a "controlled hot fusion reactor that is scalable to provide from 100 MW to 2,000 MW of clean baseload electric power."

Explore further: Image: Orion crew module at the Neil Armstrong Operations and Checkout Building, Kennedy Space Center

More information: www.kickstarter.com/projects/3… -a-railroad-to-space

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antialias_physorg
3.8 / 5 (8) Jul 25, 2013
Just did a quick calc on that last bit (which curves upward) how big the force on the payload would be.
At 2237mph that is:
(First conversion to sensible units: 2237mph is 1km/s)
If they want to launch straight up then let's assume that the radius of curvature is 1000 meters (i.e. leading up from horizontal spiral to a 1km high tower, at the end of which we have vertical launch)

The centripetal acceleration comes out to 1000 m/s^2 (or roughly 100g). Now 100g isn't something you want acting on biological matter. This is definitely a no-go for manned spaceflight. But some inert payloads might not mind such accelerations (nothing too fragile).

I guess it's buildable if you do this on (better: in) the side of a mountain.

But if they want more than the 51km height (i.e. if they want to reach escape velocity, which requires 11km/s or even LEO at 8km/s - both neglecting air resistance ) then the numbers start to look scary beacuse you start to run out of mountains that high.
.
EyeNStein
1.4 / 5 (9) Jul 25, 2013
The centrepetal acceleration (w^2*r) at 60Hz and 2.5m radius will be ~ 36,000*2.5 =90,000ms-2 or 9000g.
Not to mention that ignoring air resistance at Mach3 is ridiculous.
Good luck getting sponsors on that one.
tadchem
3.4 / 5 (5) Jul 25, 2013
The 'artist's concept' illustrates an Archimedes spiral. Given that the centripetal acceleration increases with the square of the tangential velocity, which should increase linearly with arc length under uniform acceleration, a hyperbolic spiral would be called for. Otherwise with increasing the increasing inertia will increase the lateral force on the trackway, maximizing stress (and likelihood of failure) at the base of the ramp. Stand clear! :)
hemitite
2.3 / 5 (3) Jul 25, 2013
Think of the seismic noise this earth shaking thing would generate! And then there's the massive sonic boom from the fiery streak of the payload through the atmosphere - close to the launching point it would probably be like a nuclear blast! This thing would not be a good neighbor.

On the other hand, I would pay to see it do its thing (from the safety of a well constructed bunker.)
antialias_physorg
3.3 / 5 (4) Jul 25, 2013
Had a bit more fun with math on this to calculate how big the last part needs to be if we were to have it be able to send humans to Earth orbit
(there's actually no need for this to be a spiral, a circle will do just as well if you can switch tracks fast enough at some point)

For ease of calculation let's assume extremely well trained astronaust able to withstand 10g or 100m/s*s.
Also let's go for a 10km/s escape velocity (which is already a little low and neglects air friction)

centripetal acceleration
a = v*v/r

Plugging in the above numers we get

100[m/s*s] = 100000000[m*m/s*s]/r
or
r = 1000000 m.

Erm... that's a circle of radius 1000km (vertical!)
Either I'm too tired to work this out right or this is bloody big (i.e. if you can make a structure that big you can WALK off the planet - no need for all the slingatron shennanigans).

antialias_physorg
3.4 / 5 (5) Jul 25, 2013
Finally got the kickstarter site to work. It seems that this works on a slightly different principle. The "artists concept" picture (even though it is from their webpage) doesn't seem to have anything to do with the actual mechanism envisioned.

Still they talk about "tens of thousands of Gs" and needing the object to be launched to have some sort of rocket motor to be able to szabilize/maneouver once in orbit. I'm not sure those kinds of accelerations are compatible with even the most robust rocket tech.
TheKnowItAll
1 / 5 (7) Jul 25, 2013
It looks like a defense system I came up with when I was 10! Oh wait nvm, mine was linear.
TheGhostofOtto1923
1.4 / 5 (10) Jul 25, 2013
The centrepetal acceleration (w^2*r) at 60Hz and 2.5m radius will be ~ 36,000*2.5 =90,000ms-2 or 9000g.
Not to mention that ignoring air resistance at Mach3 is ridiculous.
Good luck getting sponsors on that one.
And yet we have flown planes (SR71) at mach 3, rocket planes at mach 6, shuttles at mach 20, and are developing hybrid jet engines to operate at mach 6.

For comparison the 120mm smoothbore gun on the abrams tank fires shells at roughly mach 5.

-So where do you think there is a problem specifically? Especially some problem that the developers havent already thoroughly explored? Because, well, theyre experts and youre not?

As far as acceleration goes, ABM missiles contain sophisticated electronics and can accelerate from 0 to mach 10 in a few seconds
http://www.youtub...tgTVMcuA
TheGhostofOtto1923
1 / 5 (6) Jul 25, 2013
Still they talk about "tens of thousands of Gs" and needing the object to be launched to have some sort of rocket motor to be able to szabilize/maneouver once in orbit. I'm not sure those kinds of accelerations are compatible with even the most robust rocket tech
And of course there are smart munitions which tolerate the same acceleration as standard artillery shells.
http://en.wikiped...xcalibur
robweeve
1 / 5 (8) Jul 25, 2013
what about the elevator concept?
etudiant
5 / 5 (2) Jul 25, 2013
The structural demands on the launch spiral are ferocious. The last turn for example requires the payload to swing at near orbital speed around the launch track. I don't see how the track can hold together against the impulse of an orbital velocity payload. It seems just as likely that we would be launching parts of the track as of payload.
Imho, the engineering problems to build a linear magnetic accelerator based launcher would be less daunting.
Humpty
1.5 / 5 (8) Jul 26, 2013
"That is about 2,237 mph. If launched straight up at that speed, a payload would reach an altitude of about 51 km, neglecting air resistance, they said."

Ahhh yes, that pesky wind resistance... if we could eliminate this, we could launch anything into space.

Even crumpets and cups of tea.
Humpty
1.8 / 5 (10) Jul 26, 2013
How cum you Merkins can't use METRIC like the rest of the world does?
Urgelt
3 / 5 (4) Jul 26, 2013
Tadchem wrote, "Given that the centripetal acceleration increases with the square of the tangential velocity, which should increase linearly with arc length under uniform acceleration, a hyperbolic spiral would be called for."

Or ditch the spiral and go with a linear accelerator. Build it on the side of a mountain, and we can avoid unnecessary mechanical stresses altogether.

EyeNStein
1.8 / 5 (10) Jul 26, 2013
At those huge g loads they might as well stick it with an explosive propellant in a long barrel for 1x200th of second, to achieve the same mach 3 muzzle velocity.
Jules Verne would have loved kickstarter!
Requiem
1 / 5 (5) Jul 26, 2013
At first glance this seems pretty implausible, even just structurally.

It does occur to me, though, that if you're already building this monolothic structure it probably wouldn't be all that much more difficult to enclose the entire thing in a semi-vacuum dome or something, and maybe a very large phased-array system(or some other system that can focus a powerful beam of EM energy) on-site could help to reduce the air resistance along the payload's path into orbit.
antialias_physorg
3.7 / 5 (3) Jul 26, 2013
Or ditch the spiral and go with a linear accelerator. Build it on the side of a mountain

That seems more doable (though still technologically daunting.)
If you want to reach near escape velocity of 10km/s along a 10km stretch (which is about as long as you could build a linear accelerator along the side of the tallest mountains including digging back into the ground a fair bit) that still means we're talking about a constant 500g acceleration along the entire stretch. Not good for humans but for inert payloads (food deliveries to the ISS etc.) that would work.

If we want to have human launch capability with something like this we're well into the StarTram region
https://en.wikipe...StarTram
which calls for a quite serious megastructure rising to above 96% of the atmosphere (22km high).
Probably not a kickstarter project, that one.
TheGhostofOtto1923
1 / 5 (9) Jul 26, 2013
At those huge g loads they might as well stick it with an explosive propellant in a long barrel for 1x200th of second, to achieve the same mach 3 muzzle velocity.
Jules Verne would have loved kickstarter!
You is all so ill-educated and google-ignorant. Project Harp - one if the many superguns the world has seen.
http://en.wikiped...ect_HARP

-Even the Nazis had one.

EyeNStein
2.2 / 5 (10) Jul 26, 2013
Hi Otto, come to haunt us again?
My point was that the huge g load is numerically identical to fired from a gun barrel and emerging 5ms later at mach 3.
Not many useful satellites could stand that. And only Jules Verne would suggest its a viable launch system.
I'm with Anti-Phys and Urgelt on this one: A rail 'gun' up the side of a mountain at safe g loads is a more viable way to save fuel or boost payload. At least until the space elevator comes along.
VendicarE
3.2 / 5 (5) Jul 27, 2013
Major fail. Highest speed is in the densest part of the atmosphere.

Will never work
rwinners
1 / 5 (4) Jul 29, 2013
For geez sake, why try to beat straight line exceleration?
hemitite
1 / 5 (2) Jul 29, 2013
rwinners,

They must be from somewhere where real estate is rather expensive...
GSwift7
1.8 / 5 (5) Jul 30, 2013
Interesting idea, but if you look up non-rocket launch systems, there are many possibilities. I wonder how strong the case is for this system versus other alternatives (cost/kg)?

Build one of these ground based systems on a high place like the Atacam desert, and you're already through a big chunk of atmosphere. Equip your projectile with multiple stage rocket assists, then you don't need to get escape velocity at ground level.

Payloads would of course be restricted to bulk goods, but that is still very useful. You could launch fuel, water, non-assembled structures packed in crates, compressed gasses, spare parts, etc.

Who cares if people and delicate satellites can't ride in it. Send those up another way. The bulk materials are crucial to doing more than just hanging out in LEO for a few months.

Imagine launching a stack of soyuze heat shields and parachutes, so the soyuze didn't have to carry them up with them, for example. There's lots of heavy things that are durable as heck.
VendicarE
1 / 5 (1) Jul 30, 2013
"For geez sake, why try to beat straight line exceleration?" - hermitite

Cause spinnie things foncuse people.
TheGhostofOtto1923
1 / 5 (5) Jul 30, 2013
Not many useful satellites could stand that
Well you are guessing and you are guessing wrong. 1) The author says they can and 2) I provided you with links showing you smart artillery munitions with intricate electronics - gps, sensors, gyros, telecom, etc - which CAN tolerate those forces.
I'm with Anti-Phys and Urgelt on this one
-And they enjoy guessing as well. I enjoy making them look inadequate.
safe g loads is a more viable way to save fuel or boost payload.
No, it depends on the payload. As the author says and gswift repeats, this may be an economical way of lofting bulk materials into space. It may also make sense on other worlds.
For geez sake, why try to beat straight line exceleration?
WHY NOT?? This apparently uses less energy and takes up less space.
GSwift7
1 / 5 (5) Aug 02, 2013
Oooh, I wonder if you could build a version of this which is compact enough to use as a projectile launcher on naval vessels? I guess this isn't really a new idea, so if it was really efficient for that type of application, there would have already been an investigation.

You know, there's a factor I haven't seen anyone broach yet. You've all been talking about the force exerted on the payload, but there's also a significant force exerted on the lancher in the opposite direction. There would be a recoil force.

The quantity of moving parts needed would also be an issue, I would think.
TheGhostofOtto1923
1 / 5 (3) Aug 02, 2013
there's also a significant force exerted on the lancher in the opposite direction. There would be a recoil force
Well you could check the paper the author wrote:
http://www.hyperv...hers.pdf

-He also thought of weaponry - 'rapid-fire defense launchers' - under Applications