- #1
Algr
- 935
- 459
Hi Physics Forum!
I've been reading about the space elevator and the amazing feat of running a cable past geosynchronous orbit. It occurred to me that there might be an easier way. I may have heard about this somewhere ages ago, or maybe I made it up, but I haven't been able to find any info about it.
What if instead of running the cable to geosynchronous orbit, you had one that was about 150-200 Km long, that ran from a heavy mass like a small captured asteroid, to a hook? An object at that altitude would be orbiting much faster then the rotation of the earth, so instead of letting the cable hang down, it would spin the hook around the asteroid in the opposite direction of the Earth's rotation. Thus the speed of the hook could be adjusted so that when it enters the Earth's atmosphere it is moving at roughly the speed of the Earth's surface. (See illustration)
When viewed from the Earth, the hook would appear to enter the atmosphere at a steep angle, come to a nearly complete stop at about 15 km altitude, and then rise back into space.
(Is it proper to call the hook's path an "orbit"? It is more like a ball on a string, with centrifugal force pulling against the cable.)
You could then use aircraft to fly to the hook and attach payloads to it. The hook would lift the payloads into space, and then release them at high speed and altitude. The payloads would still need rockets to reach a stable orbit, but they would not need remotely as much fuel as a liftoff from earth.
Payloads returning to Earth could attach themselves to the hook, and be gently slowed down and lowered into the atmosphere. This would return kinetic energy to the asteroid, keeping it at the desired altitude.
I think you'd need to lift the asteroid from time to time. But since the asteroid is already in space, solar sails, ion drive, or laser boosts from Earth might do the trick.
I've been reading about the space elevator and the amazing feat of running a cable past geosynchronous orbit. It occurred to me that there might be an easier way. I may have heard about this somewhere ages ago, or maybe I made it up, but I haven't been able to find any info about it.
What if instead of running the cable to geosynchronous orbit, you had one that was about 150-200 Km long, that ran from a heavy mass like a small captured asteroid, to a hook? An object at that altitude would be orbiting much faster then the rotation of the earth, so instead of letting the cable hang down, it would spin the hook around the asteroid in the opposite direction of the Earth's rotation. Thus the speed of the hook could be adjusted so that when it enters the Earth's atmosphere it is moving at roughly the speed of the Earth's surface. (See illustration)
When viewed from the Earth, the hook would appear to enter the atmosphere at a steep angle, come to a nearly complete stop at about 15 km altitude, and then rise back into space.
(Is it proper to call the hook's path an "orbit"? It is more like a ball on a string, with centrifugal force pulling against the cable.)
You could then use aircraft to fly to the hook and attach payloads to it. The hook would lift the payloads into space, and then release them at high speed and altitude. The payloads would still need rockets to reach a stable orbit, but they would not need remotely as much fuel as a liftoff from earth.
Payloads returning to Earth could attach themselves to the hook, and be gently slowed down and lowered into the atmosphere. This would return kinetic energy to the asteroid, keeping it at the desired altitude.
I think you'd need to lift the asteroid from time to time. But since the asteroid is already in space, solar sails, ion drive, or laser boosts from Earth might do the trick.
