Fibre for space elevator

[Green Baron]

For now i would assume that mere breaking force is the first barrier. Second is getting enough construction material for such a thing. Then questions like how to hold an atmosphere, how to build a somewhat independent biosphere (elemental cycles) ...

Afterwards its instabilities from tidal forces, friction depending on height (better out of or high up in the thermosphere), pressure from solar radiation and particles, ....

But i am not a specialist ;-)

Edited November 1, 2018 by Green Baron

[YNM]

4 hours ago, tater said:

For a ring isn't the important material issue the breaking length (assuming it's spun up to 1g)?

On a ring it's going to endure hoop stress from the centripetal 'pressure', which 'pressure' is equal to it's own weight per length.

And yeah I think it's still going to be as exotic as space elevator regardless.

5 hours ago, KerikBalm said:

Ring radius could be as low as 6.4 Mm

I'd just do orbital railgun launch for that...

3 hours ago, Green Baron said:

instabilities from tidal forces, friction depending on height (better out of or high up in the thermosphere), pressure from solar radiation and particles, ....

They'll have to be counted as well, but I'm not studying astrophysics, just civil engineering.

Edited November 2, 2018 by YNM

[tater]

26 minutes ago, YNM said:

On a ring it's going to endure hoop stress from the centripetal 'pressure', which 'pressure' is equal to it's own weight per length.

Which is the same as breaking length, functionally. Breaking length is if you could stretch it between 2 poles (on an infinitely flat earth), how long befor it breaks due to its own mass. In the case of a ring, it's a circle at 1g, of that same length.

[YNM]

32 minutes ago, tater said:

Breaking length is if you could stretch it between 2 poles (on an infinitely flat earth), how long befor it breaks due to its own mass.

With sag or without sag ?

From what I read from searching on google breaking length seems to be more applicable to space elevators, not orbital rings (the max length of a cable supported/dangled only from the top). It also doesn't vary with the dimension, only with the material used.

Edited November 2, 2018 by YNM

[mikegarrison]

21 hours ago, KerikBalm said:

That is both very optimistic, and very pessimistic.

I don't think we'll see a infrastructure for space access by 2070, and I hope we won't all have killed ourselves by then.

I expect that by 2070 the world will be too busy dealing with a massive climate catastrophe to worry much about space.

[tater]

10 hours ago, YNM said:

With sag or without sag ?

From what I read from searching on google breaking length seems to be more applicable to space elevators, not orbital rings (the max length of a cable supported/dangled only from the top). It also doesn't vary with the dimension, only with the material used.

I might be wrong, it's been a (very long) while since I read about it. I recall, however, that it was stated to be the limiting factor in circumference of spinning ring structures.

[YNM]

15 minutes ago, tater said:

I recall, however, that it was stated to be the limiting factor in circumference of spinning ring structures.

They are related but the numbers isn't 1:1.