It's an interesting idea to be sure. And it's definitely one that seems kinda crazy, which probably means it could work. But there's one crucial detail missing: calculations on the centripedal/centrifugal force necessary to continue acceleration and/or direct the payload from horizontal to partially/completely vertical.<p><a href="http://en.wikipedia.org/wiki/Centrifugal_force" rel="nofollow">http://en.wikipedia.org/wiki/Centrifugal_force</a><p>a = v^2/r<p>so let's go with 1km/sec and a diameter of 5m. a = 1,000 x 1,000 / 2.5 = 400,000 m/s^2 or roughly 40,000 g<p>Now let's assume that it's a 1/4lb weight as described or 0.1kg.<p>F = m x a = 0.1 x 400,000 = 40,000 newtons.<p>Next let's assume that the piece of metal is steel and roughly cubic. It's density is around 8g/cm^3 (<a href="http://hypertextbook.com/facts/2004/KarenSutherland.shtml" rel="nofollow">http://hypertextbook.com/facts/2004/KarenSutherland.shtml</a>).<p>Mass = density x volume => volume = mass / density = 100g / 8g/cm^3 = 12cm^3<p>cube root(12) ~= 2.3 so we've got a cube with faces around 2.3cm on a side.<p>They've said that they're going to encase it in plastic so let's neglect the strength of the plastic and call it 2x the size of the cube. That brings this to 5cm x 5cm.<p>Now let's translate that into pressure.<p>P = F / a = 40,000 / (.05 x .05) = 16 MPa<p>The tensile yield strength for a regular, boring steel (A36) is 250MPa and the ultimate tensile strength (the max it can hold prior to breaking but after deforming) is 400MPa so this is fine for now.<p><a href="http://en.wikipedia.org/wiki/Ultimate_tensile_strength" rel="nofollow">http://en.wikipedia.org/wiki/Ultimate_tensile_strength</a><p>At 2km/sec you get 64MPa needed and at 7km/sec you need 784MPa all of which are within the realm of possible but rapidly heading towards the limits of material strength.<p>The 784MPa number would go down if you made the diameter bigger, too.<p>Ultimately they aren't building a thing which will disintegrate the slug (my initial thought) but it's going to have to be extremely well engineered and precisely made for balance in order to ensure that it doesn't tear itself apart. The technical combination of a steel rolling mill and a swiss watch. And due to balance issues definitely harder from a technical perspective than even the really tough portions of a rocket.<p>EDIT: didn't realize that "*" did formatting so I fixed it.<p>EDIT2: Screwed up on the calcs, assumed 10,000m/sec instead of 1,000/msec. Fixing those.
Sigh, the challenge of magnetic rail launchers and this slingatron thing is the atmosphere. Sure if you could pull a vacuum around the launch facility you <i>might</i> get close, but consider that the typical rocket launch gets maximum dynamic pressure as it goes supersonic on its way out of the atmosphere. This thing is going to hit that and <i>live</i> in that space while its going around the loop. Now compute the effect of a supersonic shockwave that is curling in on itself. The standing wave you generate it going to generate some amount of overpressure, back of the envelope, looking at four to six wavefronts collapsing on themselves as you go around the final loop of maybe 6 atmospheres?<p>There is a reason fish don't swim in a circle to build up speed to jump out of the water, because their own wake would stop them cold.<p>I wonder if someone could do a quick CFD of a payload travelling in a 7.6km/s at sea level is in the 'high hypersonic' regime (> MACH 10 closer to MACH 25) The energy you are dumping into the air at that point is going to create a pretty impressive flame front by itself. This is perhaps the coolest things about the really high speed videos of the Navy railgun project.
While 250k is peanuts compared to regular costs of rocket research, I feel 1 km/s is not that impressive of a demonstration. Rifles have achieved higher muzzle velocities as far back as 1935 [1], and ground-based systems capable of over 3 km/s have been demonstrated in the '60s and '90s only to meet with little interest [2] [3].<p>[1] <a href="http://en.wikipedia.org/wiki/.220_Swift" rel="nofollow">http://en.wikipedia.org/wiki/.220_Swift</a><p>[2] <a href="http://en.wikipedia.org/wiki/Project_HARP" rel="nofollow">http://en.wikipedia.org/wiki/Project_HARP</a><p>[3] <a href="http://en.wikipedia.org/wiki/Super_High_Altitude_Research_Project" rel="nofollow">http://en.wikipedia.org/wiki/Super_High_Altitude_Research_Pr...</a>
Backed.<p>Super-interesting concept, and the people at HyperV Technologies Corp seem to know what they're talking about, so I am excited about this. For example, their other KS project—the Plasma Jet Electric Thrusters for Spacecraft[^1]—was successful both in funding and delivering what was promised.<p>Also, you gotta love their pretty low-key / somewhat amateur'ish videos. ;)<p>[^1]: <a href="http://www.kickstarter.com/projects/2027072188/plasma-jet-electric-thrusters-for-spacecraft" rel="nofollow">http://www.kickstarter.com/projects/2027072188/plasma-jet-el...</a>
Posted this a couple days ago, and it didn't take. Very glad to see that this finally made it on the front page. Hyper-V had an impressive plasma thruster campaign, so I know they can deliver. I hope this gets funded and they can pull of the proof of concept...it seems so much better than many other ideas for small payload launch.
If this takes off one of the common uses would be flinging the last remains of dear loved ones into space.A "human dust" would surround the lower orbit. Anaerobic bacteria will thrive in the dust fed upon by deadly viruses. Skeletal remains would form microscopic spherical super-strong bone pods encasing these deadly viruses. This dust will stick to spacecraft on re-entry. The deadly viruses infect the human population resisting any medical intervention(since cooked in space) leading to the inevitable apocalypse: Zombies. Totally worth the 5$ I say. Please down vote me. I am bored.
This looks fantastic if it'd work, but I wonder if it'd be more useful to build in space, and then use it to launch little probes. No atmospheric drag.<p>I realize building it in space would be a good bit harder than on the ground. I'm just in wouldn't-it-be-cool land.
Life imitates art?<p><a href="http://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress" rel="nofollow">http://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress</a><p>Is Mike already lurking in some massive instance?!
I thought this would be totally hokey, but it wasn't. If Freeman Dyson says it's a brilliant idea, then maybe it is. I see it as being in the same category as the Hyperloop--at least worth a look at.
Reminds me of a Lofstrom Loop: <a href="http://en.wikipedia.org/wiki/Lofstrom_loop" rel="nofollow">http://en.wikipedia.org/wiki/Lofstrom_loop</a>
From other comments, it seems there are a number of basic physics and materials challenges involved in reaching orbit. However, this sort of technology used with self-guided projectiles could produce the UP/Ex launcher described by Vinge in <i>Rainbows End</i>, used for very rapid local and interstate deliveries. It takes much less energy to hit the next town over than it does to reach LEO.
I'd be all for it if it could get organic materials to space, including humans, and if it could do so without a rocket stage. The demo videos are really impressive (especially the blowing of the hole through that rug - be careful! Looks like you might have a modern weapons technology here as well) but it seems unstable and not versatile enough payload wise!
This is an interesting idea, but one that heavily relies on factual mathematics to work correctly. Even slightly get your calculations on force required to launch the vehicle and continue acceleration wrong and you've got a potential disaster on your hands when whatever it is you are launching comes falling out of the sky in your direction.<p>I really like the outside-of-the-box approach and idea, it will be interesting to see if $250,000 is enough to build something of this magnitude which will need to be tested and tested and then tested 100 more times before you could even attempt to try it in the real world.
interesting "mechanical" idea for sure, why can't you use magnetic loop to speed up the object more gradually and fire up afterwards.<p>Also really interesting references to HARP in this thread: <a href="http://en.wikipedia.org/wiki/Super_High_Altitude_Research_Project" rel="nofollow">http://en.wikipedia.org/wiki/Super_High_Altitude_Research_Pr...</a>
A few years ago, I was interested in the physics of getting LEO costs down, so I did some computer modeling.<p>This general idea was the best I could find. Put the mechanics and fuel for the vast majority of orbital insertion inside some ground-based system, instead of trying to carry it. Impossible to use with humans, but for lots of other stuff like supplies, more fuel, habitats, etc -- should work fine. At least as far as I could tell. It's much more feasible than a Space Elevator, and no new tech needs to be invented.<p>Having said that, I'm not so sure this is going to work in KickStarter format. Sure, build a bigger laboratory model, but to make this really work it's going to need a lot of cash.