On Aug/20/2018 at 6:47 PM, wrote :
On Thursday, June 21, 2018 at 5:57:15 PM UTC-7, Alain Fournier wrote:
On Jun/21/2018 at 1:35 PM, JF Mezei wrote :
On 2018-06-21 06:26, Jeff Findley wrote:

http://gassend.net/spaceelevator/breaks/index.html


Looked at "breaks at counter weight" (longest section of cable that
falls down with only counter weight going away)

Why would the falling cable become "loose" and snake ?

Since the top most portions, when being pulled down, would accelerate
more that portions below it, wouldn't the cable remain raughts and thus
no slack that allows snaking ?

Because of elasticity. I don't know how they chose a value for the
elasticity of the cable. It is very difficult to know how elastic a
cable will be if you don't know how the cable will be built. But I would
expect that a space elevator cable would become loose after snapping.

Why would it break up in space as it falls?

Take a strand of spaghetti (not fresh spaghetti, the dried variety you
will find in a grocery store) hold one end in your left hand the other
end in your right hand and bend until it snaps. You should do this over
a counter with a wall behind. After the spaghetti snaps you will have
one piece in your right hand, another piece in your left hand. But look,
you will see there is a third piece that went flying into the wall and
is now on the counter. Take another strand try again, you will get the
same result. If you repeat several times you might get a different
result once or twice, but almost every time it will break in three pieces.

When you bend a strand of spaghetti until is snaps, it will snap into
two pieces, then the whiplash will break it once more. A space elevator
cable would have much a more complex whiplash than a strand of
spaghetti. So breaking into multiple pieces isn't impossible.

Once again that will depend on the physical properties of the cable. If
instead of breaking spaghetti you tried doing the same with pieces of
wood, you wouldn't get three pieces. But if you don't use fresh pasta
and you didn't get three pieces while breaking your spaghetti, remind me
to bring my own pasta if I ever go dining at your place.

If you did multiple spaghetti breaking tests, let me propose that you
pick up all the pieces. Boil them until al dente. Strain them. Do not
rinse in cold water. Then either mix them with pesto verde or put
St-Jacques sauce over it. Delicious. If you need a recipe for the pesto
verde or the St-Jacques sauce you can send me a private e-mail.


Alain Fournier

I tried snapping spaghetti, 3 times, and 3 times in a row I ended up with 2 pieces. Maybe my spaghetti was too stale.

If it's dried spaghetti and you where holding the strands by the ends I
am very surprised by your result. I have never ended up with 2 pieces.
Maybe you don't use the same brand as I do. If that's the difference,
you should try another brand, maybe you will start loving spaghetti.

OB space elevators. If there's any asteroid mining going on, you could have climbers go up and down, put heavier cargo in them going down (from mining), and use the weight differential to power the up-climbers. No lasers required.

And how will you transfer the energy from the climbers going down
(descenders) to the climbers going up. This is not a regular elevator
with a cable moving around a pulley. The cable has to be tapered, so if
it is mobile it is difficult to keep the thickest part at geosynchronous
altitude and the thinnest part near the ground. It isn't totally
impossible to do if you have multiple sections with pulleys between each
section. But it makes a very difficult engineering project much more
difficult.


Alain Fournier