Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
"My only concern is that it wouldn't work, which I see as a problem."

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Build a really big Ferris Wheel
  [vote for,

Consider a Ferris Wheel that's rolling along the ground. As each gondola touches the Earth, it's fairly easy to step on or off, yet at the top you're moving at twice the speed of the hub. Now, increase the size of the wheel until the hub at the same altitude as low orbiting satellites. You step on the gondola and a short time later, you're in space.

Obviously, it would sink into the ground under its own weight, but what if you started it rolling fast enough that the hub reached orbital velocity? At that point, the device is essentially self supporting: There is no weight resting on the ground; in fact it could be hovering a mile or two above the ground. This would make it easier to clear mountains, and harder for terrorists to get to. At the bottom of the wheel, the gondolas are essentially at rest, so ordinary aircraft could dock with them and transfer passengers and goods. At the top, you would be moving at twice the speed of the hub, which would be a good bit more than escape velocity (which is 1.414 times orbital velocity), so getting to the Moon, Mars, etc., shouldn't be too hard.

Air resistance shouldn't be much of a problem, since the portion of the Ferris Wheel inside the atmosphere isn't moving that fast. You might be able to get rid of the hub, since centrifugal force should keep the hoop taut.

(Note that this idea isn't the same as a pinwheel, which is a rotating tether.)

samwyse, Dec 20 2002

Space tethers http://www-2.cs.cmu.../user/mnr/st/std041
Dissusion of skyhooks and pin wheels [samwyse, Oct 04 2004, last modified Oct 21 2004]

Rotavators http://www.google.c...&q=Rotavator+tether
A rotavator is a pair of spokes of the Ferris Wheel [samwyse, Oct 04 2004]


thumbwax, Dec 20 2002

       A nice idea until you tried to get it to orbital velocity. At that point, as you point out, you'd take off and lose your method of drive. Cute, nevertheless. (+)
st3f, Dec 20 2002

       See the links, it's totally covered in the literature as a variant of the standard space elevator. There are issues.
egnor, Dec 20 2002

       "You've gone and done it now, Samwise Gamgee..."
RayfordSteele, Dec 20 2002

       This is an expansion of the rotating tethers that I heard of. the wheel will need to spin constantly to keep momentium & stable (a'la gyro) also to keep COG in orbit. since it can't stop, it will be tricky to load the gondolas. Maybe a well timed pass from a plane can hook the cargo, like the way trains did with mail bags. the opposite end will need to compensate for the additional weight, maybe retractiing a counterbalance. It may need to be higher than 2 miles to avoid air resistance. This might work better as a LEO/GEO tranfer system.
the great unknown, Jan 16 2003


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