B Launching into space without fuel -- Please bare with me....

[Ryan davis]

So carbon nanotubes are incredible. Is a macrtube a possibility? If we stretched one out for centuries, and landed it on another planet, would it transfer gravity?

 

[Ibix]

You can build a space elevator in principle, which is a very strong rope to an asteroid in orbit. Then you can build a capsule that crawls up and down the rope carrying whatever. I gather that there is debate over whether carbon nanotubes could be strong enough to do this or not.

You can't really extend the idea to travel to other planets, though, because they move relative to one another and occasionally the Sun is between us and them.

I don't know what you mean by "transfer gravity", but connecting two bodies by a thread has no effect on their gravitational fields - so whatever you mean, the answer is no.

 

[sophiecentaur]

You can build a space elevator in principle,

It's such an attractive idea but it would demand a lot from our technology and is probably just not feasible. The orbit of any object on the end of the elevator would beed to have a 24hour period or the 'rope' would wrap itself around the Earth. The end would have to be at the same altitude as Geosynchronous (TV etc. ) satellites. It's well worth Googling "Space Elevator" to find a lot of enthusiastic links which are usually not based too firmly on Engineering principles. Good fun tho'.

No good for connecting planet to planet, I'm afraid, for the reasons already given but it could save a lot of fuel if spacecraft started their interplanetary flight from geosynchronous altitude; it's the first few thousand km that uses up most rocket fuel.

 

[mfb]

Only object pairs with a double tidal lock can be connected with a fixed space elevator: Both objects need to always face each other with the same side. The largest example in our Solar System is the Pluto/Charon system. We could connect them with existing materials without too much difficulty, apart from the effort of getting the cable there. We don't have an application for carrying large masses between them, however.

A space elevator for Earth would go to a counterweight some distance above geostationary orbit (36,000 km above the surface). Carbon nanotubes should be strong enough if we find a way to make them on a large scale. They'll still require significant tapering - at the surface the cable will be much thinner than at geostationary orbit where the tension is maximal.