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Re:The Slingatron: Building a Railroad to Space by jamesaguilar on Monday July 29, 2013 @07:12PM (#6124464)
Also, if I'm reading Wikipedia right, delta v to LEO is 10km/sec, and that's not counting the insane atmospheric drag on something travelling that speed at sea level. Good luck.
Re:The Slingatron: Building a Railroad to Space by msandford on Monday July 29, 2013 @07:22PM (#6124497)
So assume 1000 meters in diameter and 15km/sec for giggles.

a = v^2 / r = 15,000 x 15,000 / 500 = 450,000 m/sec^2 or 45,000g. It's on the same order of magnitude as the previous calcs.

That's obviously also a big engineering challenge because it's freaking HUGE, especially for the precision required.

The really great thing about going super-super fast is that at 15km/sec you're in space in ~10 seconds. Obviously you're going to start scrubbing speed really fast since drag is proportional to velocity squared. But you can evacuate the whole launch assembly and put some kind of an explosively opened door at the exit point and maintain your speed up until the last second.

Re:The Slingatron: Building a Railroad to Space by astrodust on Monday July 29, 2013 @07:41PM (#6124571)
The amount of drag during the acceleration phase is going to be inconsequential compared to tearing through the entire atmosphere at an angle.
Re:The Slingatron: Building a Railroad to Space by chii on Monday July 29, 2013 @08:24PM (#6124724)
what if you launched two vehiucles, but the first vehicle is more like a bullet that disintegrates and causes a wake in front for the second vehicle to pass thru with less drag?
Re:The Slingatron: Building a Railroad to Space by msandford on Monday July 29, 2013 @08:50PM (#6124815)
As soon as the first one hits the air it starts to slow down. The second one, as it's hauling ass through the wake, doesn't slow down. The difference in speeds gets very big, very quickly. As such the second one, the payload, would find itself smashing into the first one in short order.
Re:The Slingatron: Building a Railroad to Space by scotty79 on Tuesday July 30, 2013 @02:45AM (#6125649)
Since this thing can launch stuff continously maybe you could lunch few hundreds punchers to push air aside before the actual payload.
Re:The Slingatron: Building a Railroad to Space by bradleyland on Tuesday July 30, 2013 @10:01AM (#6126964)
It doesn't matter how many you send. If your scenario relies on the fact that the last in line must be the fastest of the group, it's always going to run in to the object directly in front of it.
Re:The Slingatron: Building a Railroad to Space by scotty79 on Friday August 02, 2013 @06:57PM (#6150189)
I was imagining air behaving like water. If you send first projectile it'll slow down but move some water to the sides. Second will slow down less so it'll catch up with the first one but it will also push some water to the sides. Third also will catch up with the previous ones but each subsequent one will get farther as it travels through space punched out by previous ones.

I don't think it's practical in any manner but I think such brute-forcing stream of projectiles out of atmosphere by literally punching hole in it might be nice to look at.

Re:The Slingatron: Building a Railroad to Space by astrodust on Monday July 29, 2013 @08:45PM (#6124799)
That still involves sending the first at the requisite speed, and any drafting you might get is limited at best. It'd also leave a highly unstable wake trail, as any object ripping through the air at 7-8km/s is going to tear things up.
Re:The Slingatron: Building a Railroad to Space by astrodust on Monday July 29, 2013 @07:40PM (#6124564)
Since it's such a crazy idea, why not build a gigantic dirigible to take it up to high altitude? No problem, right?
Re:The Slingatron: Building a Railroad to Space by diziet on Monday July 29, 2013 @10:21PM (#6125060)
Because what matters for getting into space / orbit is velocity to achieve orbit. An object without that velocity will simply fall down to earth instead of orbiting.

https://en.wikipedia.org/wiki/Orbit

Re:The Slingatron: Building a Railroad to Space by msandford on Monday July 29, 2013 @10:58PM (#6125164)
I believe his suggestion is to use the dirigible to lift the Slingatron into the high atmosphere where the tremendous atmospheric drag will be substantially reduced, thus making a crazy idea slightly less crazy and at the same time, more crazy.
Re:The Slingatron: Building a Railroad to Space by jamesaguilar on Monday July 29, 2013 @11:04PM (#6125179)
All I can say is I love the kind of crazy going on in this thread and all of you should buy kerbal space program.
Re:The Slingatron: Building a Railroad to Space by bradleyland on Tuesday July 30, 2013 @10:09AM (#6127003)
Newton's third law gets in the way of that proposal.

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.

If you plan to generate acceleration using mechanical force like the reference design, you'd need a massive counterweight. An equal and opposite energy would be transferred to the counterweight, so you need a lot of mass, which would require an even more massive dirigible. You also need somewhere to dissipate that energy. In the reference design, the Earth is used as the counterweight.

Alternatively, you could generate the circular motion using something like a rocket engine, in which case you might as well just use a rocket for linear acceleration and ditch the gyration mechanism.

Re:The Slingatron: Building a Railroad to Space by msandford on Monday July 29, 2013 @07:59PM (#6124632)
I love it!
Re:The Slingatron: Building a Railroad to Space by daniel-cussen on Tuesday July 30, 2013 @06:26AM (#6126127)
In the video, they address that you would still need a rocket both to circularize your orbit, and possibly recover kinetic energy lost in the atmosphere.
Re:The Slingatron: Building a Railroad to Space by Tloewald on Monday July 29, 2013 @11:16PM (#6125212)
You would, i assume, build the real thing on an equatorial mountain.