R
rogers_buck
Guest
In the distant future we may have robotic space factories capable of mining asteroids and other bodies. That's the setting for this concept.<br /><br />Imagine that our industrious robots create a giant hoop of high-quality steel alloy. The hoop is so large that it will fit over the planet earth with about 100km clearance. This is no mere coincidence...<br /><br />Fast forward to a few years later when our enormous hoop has intercepted the earth in its orbit and has oscillated in a coaxial resonance to settle around the equator. The atmosphere at 100km up would do a nice job of damping the oscillations without burning up our hoop. Once at rest, the hoop just hangs there in the sky with only enough angular momentum to keep it sationary relative to the ground. Ignoring tidal forces the pull of gravity on the hoop is uniform around its circumference and the venerable old ancient arch of the hoop carries the load by compression.<br /><br />Attached to the hoop at regular intervals are modules bolted down by the robots for shipment. Now that the hoop is safely in place about the equator, the modules come to life and drop cables the 100km to the surface of the earth. The modules are attached to the hoop by strong magnetic fields are both for lifting and electricity.<br /><br />The hoop is now ready for operation. The electric cables are plugged into the grids all over the world. Steadilly the modules apply torque to the hoop to increase its angular momentum. When desired levels are obtained the modules can begin their work. The lifting crane from a given module picks up a payload off the surface of the earth and hoists it to the 100km platform atop the module. Once safely aloft, the payload is launched on a maglev trolly onto the band itself. The payload uses the hoop as a track to accelerate to the desired linear velocity before detaching. The angular momentum stolen from the hoop is then replaced by the modules.<br /><br />This scenario ignores the earth's magetic f