space elevator

you might check out the FAQ here http://www.liftport.com/ they have answered
a lot of questions here that I would have never thought of.

Most especially avoiding debris the base of the cable will be mobile.
They also figure the cable will have a natural 7 hour resonance the can be
actively damped and LOTs of other issues that are answered.

Charles

-If Bill Gates had a nickel for every time Windows crashed... oh wait, he
does.-

"|-|erc" wrote in message
...
"G. Orme" wrote in
|-|erc wrote:
G. Orme" wrote
I don't think it is restricted to one orbit, it can come from all
directions. Also even if it came from certain directions more often
then if shaped to handle that an unlucky strike could severely
damage it.


Rod wrote:
also consider what sort of debris your cable is up against. In LEO
it will be mostly man made and in an equatorial orbit, thus shaping
your cable would seem to make sense.



How about good ole earth cable? lowest overall cross section to
tension. Ahh I get it, least probability of catastrophic failure VS
least probability of damage.

Surely a simulation would arrive at the answer, 1/4 of an arc is
vulnerable to critical angle of attack, semicircle is vulnerable to 2
holes, so around 1/3 of an arc.

3 cables would be the best design with spacers, that way at most 2
are knocked
out by a small projectile.


O
o
o
o
O o
o
o o O

composite design
Herc


So you think may be 1/3 of an arc would be optimial? The way I see
it
the answer is fairly critical. Assuming when they build it for weight
reasons it will be as light as possible relative to the debris so the
risk
of catastrophic damage will be high. Then they would build in safety
margins
but these would be as low as possible so as not to add on too much
weight.
After that point that may decide to make it thicker to carry more
weight
in which case they may be free to consider other shapes. For example an
arc
is easier for a cable car to grip on than a hollow cylinder.
Separate cables with spacers becomes similar to a mesh where the
fibres
are arranged vertically and horizontally with large holes in between to
localise the damage from debris.


I'll have to get back to you on the 1/3 figure, my simulator's a bit slow.
http://www.a1sites.com/spacecable.html

Seems a semicircle gets taken out first, and the 1/4 arc is almost
invisible to
most angles of attack, would require a lot of simulations to detect a flat
cable is the most catastrophic as on a typical run it seems to performs
the best
i.e. the lower the fraction of the arc the less visible to attack, but
also
the greatest risk of a 'wipeout' in 1 hit.

So my new design is 2 flat cables at say right angles, each with a small
risk
of total failure during which the single cable left can suffice until
repair.

Herc