Pipeline to a Space Station or just Pipe Dreams ?

I suspect there are very good scientific reasons why this is impossible and I'm looking forward to hearing them.

However, it seems to me to be an interesting concept. A tethered pipeline could revolutionize Space Station building and Space exploration by making it easier and less costly to transport materials from Earth.

There are two glaring reasons why might be impossible.

The first is the friction caused by the rotation of the Earth's atmosphere where it mmeets the vaccume of space, as experienced by space craft reentry.

As the Earth rotates on it's axis the greater friction caused by this would seem to me to be at the equator where the full diameter (greater distance) must rotate in a 24 hours whereas at either pole the turning point in 24 hours is considerably less and so the friction would be far less. If the Earth's axis didn't wobble over a year then it seems to me that there would be theoretically no friction. Even with the wobble the friction should be considerably less than at the equator. There would be twist along the length of such a pipeline but modern materials could cope with that.

The second problem would be gravity. Even a pipeline that reached out into the vaccume of space would would be effected by the forces of gravity along it's length that remained within the Earth's atmosphere and would simply fall down. Yet there seems to be a solution to this too. The natural twist of such a pipeline at the pole would mean that lightweight sails along the length of the pipe within the atmospere could give lift in a similar way to the way a helicopter works. Beyond the atmosphere, on the Space Station itself, solar sails could give a sustainable pull away from the Earth helping to keep the pipeline taut and stopping it from falling.

I'm sure ATSers will find very good reasons why this is all impossible but I hope it gives you something to think about.

Such a pipeline and Space Station would revolutionize space eploration. No longer would materials destined for Space Station expansion or Space exploration have to be shot out of the atmosphere using disportionate energy and fuel.

What is more as long as the Earth turns the Pipeline and Station would be sustainable.

One added bonus might be that a tethered Space Station would spin and thus create an artificial gravity.

Any thoughts ?

Strength of material.

While nano tech is getting us close to making a space elevator teather, there is nothing stong enough yet to be suspended from space that can handle all that force.

But a tether from the pole wouldn't have the forces acting against it that would otherwise apply. Infact at the pole the forces (spin, twist) would help keep it upright.

Originally posted by John bull 1
But a tether from the pole wouldn't have the forces acting against it that would otherwise apply. Infact at the pole the forces (spin, twist) would help keep it upright.

Last I checked gravitational fields are virtually independant of poles.(Except maybe frame dragging on a star or heavier.) Weight is still the primary issue. Also twisting, even with good, almost zero friction joints would still be the doom of a space tether.

True about gravity, my point though is that any object like a tether that extends outside of the atmosphere encounters the friction where space and atmosphere meet.

A tether on the equator (if put in place complete) would simply fall back against the spin of the Earth. At the pole this force would not be anywhere near as stong.

As for the twist. Standing directly at the pole you would be travelling far slower than anywhere else on earth. You would still rotate 360 degrees in a 24 hour period but the distance you would have moved would be virtually nil as opposed to standing on the equator where you would still rotate 360 degrees in 24 hours but because you would have travelled the full circumferance of the Earth in that time you would have been moving faster than anywhere else on the planet.

As for the effects of gravity I addressed those. Solar sails could keep the tether taut.

This idea would be impossible for the current space station (ISS) because of the very low orbit it now inhabits. Any sort of tether would wrap around the planet because to maintain a 240 mile (apprx.) altitude the station makes a complete orbit every 90 min.

If the station was placed in a much higher orbit so that it was always over the same location it becomes more feasible. But now you would be talking about a teather being thousands of miles long and not the couple hundred miles that the station currently operates at.

The whole idea is pointless from the start. A cable has two end points. Suppose one is on a space station 400 km high or so, that one is moving at several kilometers per second to keep into orbit. Your endpoint near earth needs to be moving at about the same high speed in order to preserve the cables length. So you'd still need a superfast plane or something to catch up with the cable, which makes it utterly pointless. Not even considering the friction of such a fast moving cable with the atmosphere.

Friction during reentry is further NOT caused by the rotation of the Earth's atmosphere but by the motion of the space craft relative to the air molecules of the earth's atmosphere. If the earth's rotation were really such a factor, which it is NOT, people would prefer to use polar orbits and reentry at the poles.

By the way, the material that can reach the highest altitude before snapping under its own weight is to my knowledge Dyneema, which can if my memory serves me correctly reach 200 km high before breaking. Really neat stuff I have to say.

I think for this debate we can rule out using any fibre made out of polyethylene. Just for argument sake we should consider using unobtainium.

Friction would be a huge problem if you have to drag the tether through the atmosphere at a high rate of speed from a low orbit, but a geosynchronous setup would eliminate almost all the friction because the one end would be tied into the Earth near the equator and the station would always be located over that spot. Albeit, much further out than ISS is right now.

That is the old space lift proposal, that's been covered in enough threads of its own.