DARPA's secret slingshot

DARPA space slingshot

The Slingatron program will use modern engineering and physics concepts to accelerate masses to extremely high velocities. This mechanical mass acceleration concept, based on using centripetal body forces, is fundamentally different from electro-magnetic accelerators and hence avoids the limitations of those machines. Initial studies have demonstrated the fundamental feasibility of the Slingatron concept. This program will explore the concept’s bounding limits and seek to develop uses for the technology within those limits. Included in this program will be studies of the key technologies that will allow the accelerator to achieve very high projectile energies.

This could be just what it says, or as well as / a cover for / anything from Time Travel experiments to a radical alternative to the space shuttle...

Definitely nineteenth century style grunty thinking applied to modern technological warfare.

Also, they win some sort of booby prize for calling this amazing thing the "Slingatron". W-T-F

Nice find

The concept is interesting enough, but how do you mount something humans could use into it?

The G's would be incredible for a manned vehicle to reach escape velocity from a single push. Even rockets accelerate over time, albeit with massive thrust.

That doesnt make any sense. It would take more energy than a linear launch system.
1st off rotary motion has to components to its motion at 90 deg angles to each other. One in the direction of motion and at a right angle to it is the first. A body in rotary motion wants to moves in a straight line, ie the concept, but in order to have rotary motion something has to act the the body to force it into a circular path. Gravity is the holding force in the case of a planetary body. The cord on a sling counteracts the centepidal acceleration of the rock in the pouch, and forces it into a circular path, until the cord is released. Then the rock wil travel in a straight line at velocity equal to the sum of the sum of the component velocities.
Now in order to contain the projectile and force it into a circular path the walls of the coil will have to resist the the tendency of a body in motion to stay in motion. That means frictional losses, and tremedous forces on the containment ring.
Even if using magnetic forces to "suspend" the projectile and keep it from physical contact with the containment tube, it will use more energy than moving a projectile the same mass to the same velocity.
The other engineering concerns would be the heat generated, and the tremendous magnetic fields involved. Niether electronics or biologicals much like magnetic fields of those strenghts.
It would have to be built flat, so that you didnt add the force of gravity to 1/2 the rotation and subtract it from 1/2 the rotation. But now instead of launching straight up and through the minimum amount of atmosphere, you have o lauch almost hoizontallly through the maximum amount of atmosphere, still more energy required.
The advantage the "idea" has it that you can acheive very high velocities with lower accelerations.
It offers no real advatages, but has some almost unsurmountable engineering challenges, that would take lots of money and time to work.
The quote from the darpa person said it all.

Wasn't this project canceled because it wouldn't have worked?

It's an intriguing idea - I've been following it for some time, and the people who automatically say it won't work turn out never to have looked at the actual physics. Dr Tidman has done a lot of work on this over the years and built a number of devices; his big problem seems to be basicallt that he's an outsider and the railgun people really, really don't like him.

I'm not saying there is exactly a conspiracy against the slingatron concept, but so many millions have been poured into railgun technology that they have quite an effective lobby spread over several companies - Dr Tidman doesn't. So when their engineers go around saying the Slingatron won't work (without ever actually justifying it), this becomes accepted truth.

However, there has been some sign of interest from other nations including China. I suspect the US will not be the first country to have a SLingatron with orbital capability.

It's a neat antisatellite device - no firing signature!

Of course it would never be used for humans, but there are a lot of more robust payloads that could be launched cheaply. Not to mention kinetic weapons...

It's just one more of those "out there" but perfectly sound ideas with, as you say, not enough friends on capitol hill.