what if we attach a cord onto a geostationary satellite and force it -the cord- down to earth? burns? breaks?

Question

imagine a flexible strip to rise things into space. Why can´t we do so? Where is the thin spot? Why the force of gravity doesn´t let us to hang things from orbit and such avoid the burning derived from accelerating through the atmosphere, and once in just drop the things with a parachute?

Answer 1

Damage caused by reentry into the atmosphere comes from the high speed at which vehicles reenter. The high speed causes great friction and heat. In theory, if you hang something in space from a string, you wouldn't have that friction and the string should not burn up. What you WOULD have is enormous stress on the string. Objects in orbit travel in excess of 17,000 miles per hour, speed normally applied by rocket engines during lift-off and assent by launching it at an angle relative to the earth, rather than "straight up" but in your tethered-satellite idea, the speed would be given to an object or atleast maintained [if the satellite is launched first then releases it's tether] by the Earth tugging on the tether which then tugs on the object. At greater than the 17,000ish miles per hour at an altitude high enough to reach microgravity ["orbit"] the outward force exerted by the object as it tries to be flung from the earth would pull like the dickens on the tether. Remember, orbit is achieved when an object speeds past the earth at the same speed it falls towards the earth [or close to, someone with exact numbers can set you straight on that] so that it effectively falls at the earth, misses the earth, then keeps falling at the earth in a cycle that causes the object to fall AROUND the earth. For the tether idea to work, you'd need to keep the object moving faster than orbital speed so that it travels past the earth faster than it falls, which is where the great strain on the tether comes from. Difficult but not impossible to overcome. Pracitcally, the idea has flaws in that it renders a section of airspace entirely unsuable at any altitude, a problem that grows worse as the tether idea gains popularity. The tether would have to be so strong to counter the outward force of it's satellite that any aircraft hitting it would be in for some trouble.

Answer 2

There are a lot of forces involved. For most of the cord's length, the cord's own weight will pull it downwards with enough force to break most materials, except maybe the carbon nanotubules, and maybe diamonds.

Closer towards the satelite, the orbital forces make "pulling ot down" a little inaccurate. Suffice it to say that the different distances from the earth require different orbital speeds, so the cord tends to rip sideways.

The atmosphere might set up unpleasant vibrations in such a cord, even if it wouldn't snap it. This might be enouigh to shake the satellite out of orbit, and at the very least, it would make a very annoying buzzing sound that could be heard for miles from the site.

Aside from the cord, there's the problems with the satellite. Satellites need a certain amount of fuel to keep their proper place. Pressurized cans, similar to aerosols do the trick for current satellites, but they tend to be good for only about ten years. With a cord, the added weight should make a lot more fuel necessary, and refueling would be needed.

Station keeping is a major safety issue. Should the satellite ever get out of of the proper orbit, the cord would wrap around the planet several times before dragging the satellite down with it.

At the orbital speeds involved, this rope would hit with a lot of force, any such accident would be about equivalent to setting off a string of several thousand atom bombs around the equator. Columiba, Equador, and many nations in Africa and southeast Asia would be rather upset about that... so there are some major safety concerns.

The idea does have a lot of discussion in Science Fiction, with Arthur C. Clark having worked out the basics back in the 50s. The idea has been given a lot of names, Beanstalk, Space Elevator, Sky Hook, Stairway to heaven, etc.

Interestingly enough, since the end of the string would need to be farther out than geostationary orbit, anything that gets sent to the end will fly off into an orbit beyond it.

Answer 3

If we could stretch a cord that far we could tack it into place on a spot on the equator. Also if you used a cord that long you would have to move the satellite farther out because the center of gravity follows that orbit, and a cord that long would alter that center of gravity drastically, Also we could do that its just that the cord would have to support its own weight. You also cannot have the cord physically touch the thing following it or you could damage the cord. Scientists have proposed using a space elevator using the same principle. We can use something other than cardon nanotubes. We can use another form of carbon, diamonds. Scientists can now grow diamonds in labs at about a carrot an hour, as more advances come in we should be able to grow them much faster.

Answer 4

The challenge is the weight of the cord vs. its tensile strength. You could do it today if you had a rocket powerful enough to lift a payload weighing hundreds of tons. The hope of carbon nano tubes is to create a very light cord strong enough to do the job. By the way, you can't use a parachute from space. Whatever object you want to get back to the ground is also in orbit with you and must be knocked out of orbit (or allowed it to decay) and reenter the atmosphere where friction will cause heat. But if you had a tether in place, a reentry vehicle could just crawl slowly down the cord and never heat up. It's not that crazy--the first cord could be very very small. It only needs to be big enough to support a small vehicle that runs up another very small cord. Repeat that process until you have a tether.

Answer 5

This is an old idea which originated in Tsarist Russia. It is also an idea which some people up near Seattle, Washington are working toward making a reality. Check out the websites listed below. The second one is from the LiftGroup, but it's a little thin on details. However, they do have a countdown clock running for the launch of their space elevator. The first website goes into much deeper detail. Have fun:-)!

Answer 6

The only problem is that no one has come up with 23,000 miles of cord that fits in a satellite to be able to drop it from orbit.

Also, no current material that we have is strong and light enough to actually support its own weight at that height. Carbon nanotubes come close, and we may someday be able to do it.

The device you are describing is known as a beanpole, and has been a feature of many science fiction stories for decades. If we can get one built, it will revolutionize how we are able to utilize space.

Answer 7

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Answer 8

Right now we can't do that. A cord 200+ miles long would be too heavy and would not be able to support itself. Carbon nanotubes look promising in this area.

Answer 9

That is pretty much the idea behind the space elevator.

Answer 10

Fall down to earth.