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Whipcrack satellite launcher

Ktang!
  (+11, -1)(+11, -1)
(+11, -1)
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This is an ill-conceived idea. I suggest you skip the next four paragraphs if you're in a hurry.

So. A problem with launching satellites is that, even if you can get them close to orbital height, you have to turn left and get them up to orbital velocity, which is (for low orbit) about 18,000 mph, or something like Mach 24. Ideally, you need to do this without crushingly large accelerations.

So. A whip works by transferring momentum gradually from the long, heavy body of the whip into the small, light tip. At ground level, the tip of a hand- cracked whip will allegedly reach supersonic speeds. (Yes, I know, there are all kinds of arguments about where whip cracks come from, but the tip is certainly accelerated hugely relative to the input motion.)

So. Get your launch vehicle up to near- orbital altitude, and release a long (maybe very long, or possibly extremely long) tapering, flexible strap shortly before apogee. The tip of the strap carries a very small thruster, and also the satellite to be launched. The thruster extends the strap away from, and slightly downward from, the launch vechicle, just as the main rocket angles over at the top of its flight and starts to point downward.

At a cunningly chosen moment, the main rocket fires its final booster, this time aiming downwards and parallel to the extended strap. Soon, it passes the tethered satellite, leaving a loop of tether behind it. In a twinkling of an eye, it reaches the limit of the tether and, in the same twinkling, the satellite-carrying tether-tip flicks the satellite deftly skyward [EDIT spaceward. Definitely spaceward. Not skyward.], at a speed many times that of the now-descending rocket.

MaxwellBuchanan, May 04 2008

[link]






       //deftly skyward//
Don't get me wrong, I like the idea.
But I think I see ya problem right there!
gnomethang, May 04 2008
  

       Why not ground-based ? world's most interesting trebuchet (or ballista or whatever it is)   

       sp. daftly
FlyingToaster, May 04 2008
  

       //sp. daftly// [FlyingToaster], if you're not going to take this seriously, then neither am I.
MaxwellBuchanan, May 05 2008
  

       When a whip cracks, the sonic boom is caused by the tip being *rotated* (as the radius of the inscribed circle and the weight of the stationary "tip" both approache zero) with a linear displacement of almost nothing.   

       What you want to do is waaaay beyond the physical strengths of modern materials... you want to flex and rotate something at mach24... what will happen is the end will snap off possibly leaving the payload spinning like hell, but with a forward velocity no different than the original velocity of the booster rocket.   

       I still [+]'d it for the picture and for the possibility of a ground-based mach1'ish trebuchet spinoff.   

       (when I was a kid I practised for weeks and weeks with a 30' dogteam whip and only got it to crack a couple times when nobody else was around...)
FlyingToaster, May 05 2008
  

       Hmm. Welllllll, I'm not so sure. The basic idea is that the tip gains in velocity relative to the motion of the handle. Now, I'd imagine that the accelerations would be dependent on the geometry of the situation. So, with a big enough whip, you might be able to get (say) a 20:1 ratio of velocities without any unfeasible peak accelerations.
MaxwellBuchanan, May 05 2008
  

       //When I was a kid//   

       I had a nylon strap that was used to tie down airplanes in the Air Force. I tied it with stainless steel wire to the end of a long green stick with twist pliers.   

       It would make a fantastic crack.   

       It once got away from me and I popped myself full force on the back of the calf. I had a really bad welt that didn't disappear for about two weeks.   

       I love this idea. When they get that carbon nanofiber ribbon together, we'll be in business.
nomocrow, May 05 2008
  

       Why use a whip? If we roll a large enough towel up, we can toss the payload into the air, flip it in the heatshield and off it goes. I think ACME might have a giant sling shot that we can use for the initial toss.
Ozone, May 06 2008
  

       // I suggest you skip the next four paragraphs //   

       Thanks, that really did save time ;)
phundug, May 06 2008
  

       I had been toying with this idea but I didn't post it because I hadn't really thought through the aiming and delivery at the end of the whip. I see now that that isn't an issue yet.   

       I'm still thinking about it.
wagster, May 06 2008
  

       Mmmm, perhaps an low earth orbit bolas (boleadoras)?
4whom, May 07 2008
  
      
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