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Imperito
04-04-2002, 05:39 PM
If someone put a thick cable many km long on a space shuttle, attached one end to a satellite, and dropped the other end to the earth, what would happen?

Picture a master lock tied to some fishing line, with the other end in your hand. You could sling it around in circles, and the lock would just "orbit" your hand.

Would a satellite in the same condition do the same thing? Would it get slung around the earth like a giant weed whacker?

I dont think the cable would burn up in the atmosphere, b/c it would not be moving through the atmosphere. Anyone standing on the ground would just see it there, like a really thin tower.

Now, back to the lock. An ant on your hand could climb out on the fishing line and be standing on the lock, provided she did not fall. Could a person shimmy up the cable and be in space?

Does anyone have a spare space shuttle so we can try this out?

Also, if this did happen, would the result be a tall structure or a low flying spacecraft?

xlnk
04-04-2002, 06:22 PM
it would burn up, when dropped it would be moving through the atmosphere to the ground.

heh a satellite would not be able to sling around the earth, unless you had alot fo people to grab on to the rope and sling it, if it made it through the atmosphere, or use a mechanism, but if you got it moving, it would either move out of orbit, which would either send it flying off into space or come down burning through the atmosphere. If it stayed on its course, the rope would rap around the earth, if held back, or it would go any which way.

ygfperson
04-04-2002, 06:59 PM
shimmy up the cable? that's mount everest * 100!

Imperito
04-04-2002, 07:19 PM
I'm not so sure, xlnk. If you consider that any point on the surface of the earth is rotating about the center of the earth at considerable velocity, it would sling around, and if the satellite is in a geosnycronous (sp?) orbit, it would not get pulled down from orbit, would it?

yfg, what if it was a looping cable, and there were pulleys at the top and bottom, like a flagpole. You could use an engine to pull a person up.

xlnk
04-04-2002, 07:36 PM
i agree, if it was in a geosyncronous orbit it would follow the same speed as the earth, so one orbit a day. The magnetic field, what would we do without it. :)

shtarker
04-04-2002, 08:54 PM
Well it might be possible, however there are a few limitations of the type of orbit you'd need:

The space shuttle was designed only for a low earth orbit and it would be risky to try and reach the altitude needed for a geostationary orbit.
The altitude would put it just below the edge fo the outer van allen belt, so the person would have to shimmy up through a few kilometers of lethal radiation.
Sun spots would cause the van allen belts to flare up, putting a pretty big electric charge on the cable, which would essentially act as an earth lead.
The satelite would have to be directly above the equator to put it in a geostationary orbit (as opposed to a geosynchronous where the orbit looks like those in the movies where it traces out a sort of cos wave pattern).
And also the weight of the cable would most likely pull the satelite down out of orbit pretty quickly.


Newton considered a similar thing using a really tall tower and concluded that at a certian height, the spin of the earth would eventually cause total weightlessness for anything on the tower. However it would be unfeasibly tall.

Imperito
04-04-2002, 09:41 PM
Well, correct me if I'm wrong, but wouldn't a sat in an unnatural orbit (too low for it's speed) tend to ascend to a natural orbit? Wouldn't this tendancy pull away from the earth, and make the satellite essentially ballast on the cable.

The majority of force would be in the cable, the sat is essentially the lock on the end of the fishing line that keeps it taut.

As for lightning, couldn't you use a nonconductive cable?

As for radiation, isn't there shielding for that?


Maybe sat is the wrong term. This would not be something orbiting the earth that would have a connection down, this would be something tied to the earth, slung around in circles by it's rotation.

shtarker
04-04-2002, 09:58 PM
>>As for lightning, couldn't you use a nonconductive cable?

No its not just lightening, charged particles in the van allen belts would put a pretty significant change on anything up in a geostationsary orbit.

>>As for radiation, isn't there shielding for that?

And you really start taking up huge amounts of weight.


What I am saying is that although it may be theoreticly possible, physical limitations make it pratcially impossible.

Drewpee
04-05-2002, 08:54 AM
Have a look at:

http://flightprojects.msfc.nasa.gov/fd02_elev.html

and

http://www.space.com/businesstechnology/technology/space_elevator_020327-1.html

This was attempted using the space shuttle and a 'satellite' on a long teather from it. Didn't work so good, I beleive there were resonance problems or something...
Still, people are researching it.