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Sun 8 Feb, 2004 07:37 am
Near term we could assemble 4 or 6 telescoping tubes up to 100 meters long in a bundle connected by air locks near each end. This would allow you to take a 'walk' up to 600 meters before you were repeating your path. This would give the illusion of spaciousness even if the tubes were 4 meters at the large end and one meter at the small end. A 14 meter disk for radiation shielding would cover the bundled large end. Properly oriented the entire station would have reduced radiation. During a coronal mass ejection it would be prudent to huddle at the big end as close to the disk as possible to reduce radiation exposure.
Every other time the craft was shaded by Earth or an other body, the attitude control would be shut down, and the crew would have a 'foot' race all in the same direction. This would cause the station to tumble end over end creating perhaps 1/2 g at the small ends of each tube. The severe coriolis effect would help condition the crew to tolerate coreless. The tumbling would be stopped by 'running' the last race (or two) in the opposite direction. Please comment, refute or embellish. Neil
That's about as far over my head as the space station itself.
Re: Traveling space station
neil wrote:Every other time the craft was shaded by Earth or an other body, the attitude control would be shut down, and the crew would have a 'foot' race all in the same direction. This would cause the station to tumble end over end creating perhaps 1/2 g at the small ends of each tube.
Not entirely positive I get the picture here. If the tube with the crew inside it is not rotating, and then the crew inside do something (like run), and afterwards the tube with the guys inside is rotating, where did the angular momentum of the crew-tube system come from, since the angular momentum of a closed system cannot change?
If the race is run in two tubes on either side if the center of mass, angular momentum is produced by the crew moving in the same direction much as a hamster wheel rotates. Movement in the other tubes will add roll to the tumble. Neil
In a hamster wheel, there is no angular momentum produced, since the hamster's angular momentum is equal and opposite to the wheel's, and when the hamster stops, the wheel stops. If the hamster were to leap out of the wheel while it was in motion, it would keep moving, of course, but only because when the hamster collides with the floor or wall of the cage, the Earth will acquire his angular momentum. Since the space station is an isolated system, this is not possible, and under no circumstances can net angular momentum of the station-crew system be changed unless an outside system interacts with it. If you are talking about two tubes that acquire equal and opposite angular momentum, so that the net change is zero, there is nothing to rule it out.
Hi brandon: Your physics seems correct, but I think the hamster could rotate his cage in free fall = no gravity by digging in his toenails. When he stops running, the cage would not stop as the hamster is weightless, but still has inertia. If he jumps out, the wheel will not spin as long as the system lost inertia. The hamster likely would not jump off the wheel a second time as he would bounce off the wall spinning, I think. Neil
neil wrote:Hi brandon: Your physics seems correct, but I think the hamster could rotate his cage in free fall = no gravity by digging in his toenails. When he stops running, the cage would not stop as the hamster is weightless, but still has inertia. If he jumps out, the wheel will not spin as long as the system lost inertia. The hamster likely would not jump off the wheel a second time as he would bounce off the wall spinning, I think. Neil
Hey, Neil.
It might simplify matters if I just state that the angular momentum of an isolated system cannot change. If a hamster cage were isolated in outer space, and initially had angular momentum zero, noithing done by any creature or machine inside the cage could give a net angular momentum to the whole system. A rocket can do things like that because it ejects matter, and the entire system of rocket and spent fuel, would still have angular momentum zero. Every physicist in the world agrees that this is impossible. It may be possible to give the separate parts of the cage and its contents individual angular momenta, but they would have to have a vector sum of zero.
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