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Re: Towards routine, reusable space launch.

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  Re: Towards routine, reusable space launch. Doc O'Leary  <droleary@2017usenet1.subsume.com> - 2018-06-11 22:18 +0000
    Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-11 20:52 -0700
    Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-12 06:34 -0400
      Re: Towards routine, reusable space launch. Doc O'Leary  <droleary@2017usenet1.subsume.com> - 2018-06-12 14:36 +0000
        Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 14:29 -0700
        Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-12 19:00 -0400
          Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 02:15 -0400
            Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 01:27 -0700
            Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-13 06:46 -0400
              Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 16:28 -0400
                Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 14:38 -0700
                Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-14 05:22 -0400
                  Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-14 15:44 -0400
                    Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-15 07:52 -0400
                      Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-15 21:33 -0400
                        Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 10:38 -0400
                          Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-16 17:51 -0400
                            Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-17 02:16 -0700
                              Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-17 15:49 -0400
                                Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-17 16:52 -0400
                                  Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-18 02:44 -0400
                                    Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 00:05 -0700
                                      Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-18 14:27 -0400
                                        Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 19:39 -0700
                                Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-17 18:26 -0700
          Re: Towards routine, reusable space launch. Doc O'Leary  <droleary@2017usenet1.subsume.com> - 2018-06-13 12:57 +0000
            Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 14:35 -0700
              Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 17:55 -0400
                Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 21:44 -0700
                Re: Towards routine, reusable space launch. Doc O'Leary  <droleary@2017usenet1.subsume.com> - 2018-06-14 22:02 +0000
              Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-13 19:39 -0400
                Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 21:53 -0700
                  Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-14 19:46 -0400
                    Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-15 07:56 -0400
                      Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-15 19:21 -0400
                        Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-15 19:18 -0500
                          Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-15 21:05 -0400
                          Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 10:06 -0400
                            Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 13:21 -0400
                              Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 13:57 -0400
                                Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 14:19 -0400
                          Re: Towards routine, reusable space launch. mvp@web1.calweb.com (Mike Van Pelt) - 2018-06-19 18:38 +0000
                            Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-19 21:27 -0600
                        Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-15 22:13 -0400
                          Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-15 20:34 -0700
                            Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 09:54 -0400
                              Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-18 13:45 -0500
                                Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-18 21:06 -0400
                                  Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 20:00 -0700
                                    Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-19 19:45 -0400
                                      Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-19 22:12 -0400
                                        Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-20 20:21 -0400
                                      Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-20 17:13 -0700
                                        Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-20 20:34 -0400
                                        Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-21 06:26 -0400
                                          Re: Towards routine, reusable space launch. Steve Carroll <frelwizzen@gmail.com> - 2018-06-21 03:48 -0700
                                          Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-21 13:35 -0400
                                            Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-21 20:57 -0400
                                              Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 23:22 -0500
                                            Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-22 07:18 -0400
                                              Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-22 17:45 -0400
                                                Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-22 19:58 -0400
                                                  Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-23 03:39 -0400
                                                    Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-23 08:38 -0400
                                                      Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-23 17:18 -0400
                                                    Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-23 09:58 -0400
                                                    Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-24 00:53 -0500
                                                Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-23 08:34 -0400
                                  Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-18 22:17 -0500
                                    Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-19 00:45 -0700
                                      Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-19 15:58 -0500
                                        Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-19 14:38 -0700
                                          Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-20 15:42 -0500
                                            Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-20 16:58 -0400
                                              Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-25 20:44 +0000
                                            Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-20 17:07 -0700
                                              Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 23:24 -0500
                                                Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-21 21:38 -0700
                                        Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-19 21:35 -0600
                                Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-19 17:01 +0000
                            Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 22:39 -0500
                Re: Towards routine, reusable space launch. "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-06-14 15:39 -0700
                  Re: Towards routine, reusable space launch. "hanson" <hanson@quick.net> - 2018-06-14 15:53 -0700
            Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-14 04:47 -0400

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#690857

On Jun/16/2018 at 1:57 PM, Jeff Findley wrote :
> In article <pg3gub$lov$1@dont-email.me>, alain245@videotron.ca says...
>>
>> On Jun/16/2018 at 10:06 AM, Jeff Findley wrote :
>>> In article <pg1l1n$440$2@gioia.aioe.org>, invalid@invalid.com says...
>>>>
>>>> how about a Space Slingshot ?
>>>
>>> A fool and his money are soon parted.
>>>
>>> They're not getting enough money to actually develop and build the
>>> thing.  They're raised what $40 million or something?  They'll need a
>>> hell of a lot more than that to turn their design into a reality.
>>
>> Are you two talking about SpinLaunch? If no, what do you mean by Space
>> Slingshot?
> 
> That was my guess.  I personally don't think SpinLaunch is viable, at
> least not without a heck of a lot of development.  G loads will be
> pretty crazy, so you can't use it for much except bulk cargo.

On Feb/25/2018 at 11:32 AM, (In sci.space.policy) I wrote:
"I might be wrong but I suspect those proposing SpinLaunch are aware of
the problems. Their business plan is probably more about collecting
investors money than about putting anything in orbit."

I haven't seen anything since that would make me change my mind about 
that. So they aren't going to get any investment money from you and I.


Alain Fournier

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#691229

In article <pg1l1n$440$2@gioia.aioe.org>, Sergio  <invalid@invalid.com> wrote:
>how about a Space Slingshot ?

Do you mean a rotating skyhook?

Some of those ideas are ... intriguing.  And have much less
stringent requirements on materials.

-- 
Mike Van Pelt       |  "I don't advise it unless you're nuts."
mvp at calweb.com   |   -- Ray Wilkinson, after riding out Hurricane
KE6BVH              |      Ike on Surfside Beach in Galveston

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#691328

mvp@web1.calweb.com (Mike Van Pelt) wrote:

>In article <pg1l1n$440$2@gioia.aioe.org>, Sergio  <invalid@invalid.com> wrote:
>>how about a Space Slingshot ?
>
>Do you mean a rotating skyhook?
>
>Some of those ideas are ... intriguing.  And have much less
>stringent requirements on materials.

A rotating skyhook needs to restore energy after passing a ship
upwards.  Either it needs at least as much returning mass as
departing, or needs (maybe electric ion) booster to retain station.
-- 
We are geeks.  Resistance is voltage over current.

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#690805

On 2018-06-15 19:21, Alain Fournier wrote:

> Yes. But I think I am a little less optimistic than you about it 
> becoming practical in the future. If we have fantastic materials in the 
> future, maybe an elevator will become more practical,


Apart from lifting geostationary satellites to just below orbit and then
let them use their own thrusters to position to their assigned
slot/longitude, what other use would a space elevator have ?

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#690810

JF Mezei <jfmezei.spamnot@vaxination.ca> wrote on Fri, 15 Jun 2018
22:13:01 -0400:

>On 2018-06-15 19:21, Alain Fournier wrote:
>>
>> Yes. But I think I am a little less optimistic than you about it 
>> becoming practical in the future. If we have fantastic materials in the 
>> future, maybe an elevator will become more practical,
>>
>
>Apart from lifting geostationary satellites to just below orbit and then
>let them use their own thrusters to position to their assigned
>slot/longitude, what other use would a space elevator have ?
>

You go above the GEO point on the cable and get flung on
interplanetary trajectories.


-- 
"Some people get lost in thought because it's such unfamiliar
 territory."
                                      --G. Behn

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#690841

On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
> JF Mezei <jfmezei.spamnot@vaxination.ca> wrote on Fri, 15 Jun 2018
> 22:13:01 -0400:
> 
>> On 2018-06-15 19:21, Alain Fournier wrote:
>>>
>>> Yes. But I think I am a little less optimistic than you about it
>>> becoming practical in the future. If we have fantastic materials in the
>>> future, maybe an elevator will become more practical,
>>>
>>
>> Apart from lifting geostationary satellites to just below orbit and then
>> let them use their own thrusters to position to their assigned
>> slot/longitude, what other use would a space elevator have ?
>>
> 
> You go above the GEO point on the cable and get flung on
> interplanetary trajectories.

Yes!

You would also likely put at least one cable above GEO rotating in a 
plane perpendicular to the main cable. So you can give an extra push for 
interplanetary trajectories and to fine tune in which direction you 
depart for said trajectories.

You can also jump off at an altitude of about 15000 km (that figure is 
from the top of my head, it might be more or might be less). From there 
after a few passes of aero-braking you can reach LEO with very small 
thrusters.

For polar orbits, you use the rotating cable above GEO mentioned above. 
But instead of using it for extra push you get off while it is 
subtracting some speed but not quite in the direction of rotation of the 
cable. So you subtract some speed in the direction of rotation of the 
cable and give some speed in the north-south axis. You then use 
aero-braking again to lower apogee, and a small thruster to raise 
perigee. Note however that using the elevator to reach polar orbits in 
this way isn't obvious. You would want a long and fast rotating cable 
and you would want it far above GEO, it might not be practical to do so.

Building an elevator, with current technologies, is outrageously 
expensive. But if you have one, it can be very useful.


Alain Fournier

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#691078

On 6/16/2018 8:54 AM, Alain Fournier wrote:
> On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
>> JF Mezei <jfmezei.spamnot@vaxination.ca> wrote on Fri, 15 Jun 2018
>> 22:13:01 -0400:
>>
>>> On 2018-06-15 19:21, Alain Fournier wrote:
>>>>
>>>> Yes. But I think I am a little less optimistic than you about it
>>>> becoming practical in the future. If we have fantastic materials in the
>>>> future, maybe an elevator will become more practical,
>>>>
>>>
>>> Apart from lifting geostationary satellites to just below orbit and then
>>> let them use their own thrusters to position to their assigned
>>> slot/longitude, what other use would a space elevator have ?
>>>
>>
>> You go above the GEO point on the cable and get flung on
>> interplanetary trajectories.
> 
> Yes!
> 
> You would also likely put at least one cable above GEO rotating in a
> plane perpendicular to the main cable. So you can give an extra push for
> interplanetary trajectories and to fine tune in which direction you
> depart for said trajectories.
> 
> You can also jump off at an altitude of about 15000 km (that figure is
> from the top of my head, it might be more or might be less). From there
> after a few passes of aero-braking you can reach LEO with very small
> thrusters.
> 
> For polar orbits, you use the rotating cable above GEO mentioned above.
> But instead of using it for extra push you get off while it is
> subtracting some speed but not quite in the direction of rotation of the
> cable. So you subtract some speed in the direction of rotation of the
> cable and give some speed in the north-south axis. You then use
> aero-braking again to lower apogee, and a small thruster to raise
> perigee. Note however that using the elevator to reach polar orbits in
> this way isn't obvious. You would want a long and fast rotating cable
> and you would want it far above GEO, it might not be practical to do so.
> 
> Building an elevator, with current technologies, is outrageously
> expensive. But if you have one, it can be very useful.
> 

we don't have one, and never will.  It is a joke among Engineers.

What would is the monthly insurance payment for it?  if it fell over ?

how many miles would the top swing back and forth ?

How much sideways force is pushed on it by a 20 mph wind ?

how much does one guy wire weigh ? (assume 20,000 km elevator height)

how much does one copper cable weigh if moving 200 amps ?

What voltage is needed at the ground to feed the copper wires ?  assume
500 V AC needed at the top.

How much does the tower weigh counting only the copper wires, main
cable, and guy wires ?

> 
> Alain Fournier

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#691148

On Jun/18/2018 at 2:45 PM, Sergio wrote :
> On 6/16/2018 8:54 AM, Alain Fournier wrote:
>> On Jun/15/2018 at 11:34 PM, Fred J. McCall wrote :
>>> JF Mezei <jfmezei.spamnot@vaxination.ca> wrote on Fri, 15 Jun 2018
>>> 22:13:01 -0400:
>>>
>>>> On 2018-06-15 19:21, Alain Fournier wrote:
>>>>>
>>>>> Yes. But I think I am a little less optimistic than you about it
>>>>> becoming practical in the future. If we have fantastic materials in the
>>>>> future, maybe an elevator will become more practical,
>>>>>
>>>>
>>>> Apart from lifting geostationary satellites to just below orbit and then
>>>> let them use their own thrusters to position to their assigned
>>>> slot/longitude, what other use would a space elevator have ?
>>>>
>>>
>>> You go above the GEO point on the cable and get flung on
>>> interplanetary trajectories.
>>
>> Yes!
>>
>> You would also likely put at least one cable above GEO rotating in a
>> plane perpendicular to the main cable. So you can give an extra push for
>> interplanetary trajectories and to fine tune in which direction you
>> depart for said trajectories.
>>
>> You can also jump off at an altitude of about 15000 km (that figure is
>> from the top of my head, it might be more or might be less). From there
>> after a few passes of aero-braking you can reach LEO with very small
>> thrusters.
>>
>> For polar orbits, you use the rotating cable above GEO mentioned above.
>> But instead of using it for extra push you get off while it is
>> subtracting some speed but not quite in the direction of rotation of the
>> cable. So you subtract some speed in the direction of rotation of the
>> cable and give some speed in the north-south axis. You then use
>> aero-braking again to lower apogee, and a small thruster to raise
>> perigee. Note however that using the elevator to reach polar orbits in
>> this way isn't obvious. You would want a long and fast rotating cable
>> and you would want it far above GEO, it might not be practical to do so.
>>
>> Building an elevator, with current technologies, is outrageously
>> expensive. But if you have one, it can be very useful.
>>
> 
> we don't have one, and never will.  It is a joke among Engineers.
> 
> What would is the monthly insurance payment for it?  if it fell over ?

You put the cable on an east coast. You also put a system to cut the 
cable at something like 10000 km high. If the cable breaks below that 
10000 km the upper part doesn't fall it goes up, the bottom part falls 
in the ocean, where it isn't likely to cause damage. If the cable breaks 
higher than 10000 km, you cut it at 10000 km, the bottom 10000 km falls 
once again in the ocean. The two other parts won't fall to the ground, 
the lower part will probably be in an elliptical orbit, the higher part 
might be in an escape trajectory. So the damage from a cable breaking 
doesn't have to be high. It might be a little difficult to explain that 
to an insurance company, but if you can pay for the cable, you should be 
able to cover the damages.

> how many miles would the top swing back and forth ?

Why do you care?

> How much sideways force is pushed on it by a 20 mph wind ?

Why do you care?

> how much does one guy wire weigh ? (assume 20,000 km elevator height)

Why would you put a guy wire? Don't assume 20,000 km elevator height, 
assume 70,000 km, you want the top of the cable to pull up the bottom of 
the cable, so you have to go beyond GEO height.

> how much does one copper cable weigh if moving 200 amps ?

Don't put a copper cable. Send energy to the climber using some kind of 
beamed energy. (A laser on the ground, maybe another one in 
geosynchronous orbit, and photocells on the climber to convert back to 
electricity. Or something of that kind.)

> What voltage is needed at the ground to feed the copper wires ?  assume
> 500 V AC needed at the top.
> 
> How much does the tower weigh counting only the copper wires, main
> cable, and guy wires ?

The copper wires and guy wires are nonexistent and therefore weigh 
nothing. As for the main cable, it weighs way too much. That is why I 
said in the message to which you are replying that "Building an 
elevator, with current technologies, is outrageously expensive." I don't 
think we will ever have one.


Alain Fournier

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#691159

Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
21:06:46 -0400:

>
>You put the cable on an east coast. 
>

Uh, do you mean west coast?  If the thing falls isn't it going to lay
out along the direction of spin, which means it falls to the west.


-- 
"Insisting on perfect safety is for people who don't have the balls to 
    live in the real world."   
                      -- Mary Shafer, NASA Dryden

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#691303

On Jun/18/2018 at 11:00 PM, Fred J. McCall wrote :
> Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
> 21:06:46 -0400:
> 
>>
>> You put the cable on an east coast.
>>
> 
> Uh, do you mean west coast?  If the thing falls isn't it going to lay
> out along the direction of spin, which means it falls to the west.

Uh, no I meant east coast.

At least one of the two of us is making a very silly mistake here. So 
I'm going to say some very obvious things, I don't know where the very 
silly mistake is but it should be among these obvious things.

The Sun rises in the morning towards the east and sets in the evening in 
towards the west. But it isn't really the Sun that is making an east to 
west journey, the perceived motion of the Sun is caused by the rotation 
of Earth in the opposite direction. So the direction of Earth's spin is 
eastward. If a space elevator is anchored to Earth near the equator, it 
will necessarily spin with Earth, the direction of spin of the elevator 
is also eastward. So yes as you said the elevator is going to lay out 
along the direction of spin, but that is eastward not westward. If the 
elevator cable breaks, the bottom part will start falling while spinning 
eastward, at first spinning at 1 revolution per day, just like Earth. So 
at first in the rotating reference frame of the ground it is just going 
down. When you tighten up something that is rotating, like a figure 
skater pulling in their arms, that increases the rotation rate. So the 
cable will be going eastward faster than Earth.


Alain Fournier

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#691322

On 2018-06-19 19:45, Alain Fournier wrote:


> at first in the rotating reference frame of the ground it is just going 
> down. When you tighten up something that is rotating, like a figure 
> skater pulling in their arms, that increases the rotation rate. So the 
> cable will be going eastward faster than Earth.

Would such a system be planned with enough "counterweight" above
geostationary orbit to pull the cable up enough such that its weight at
altitude 0 would be 0 ?

Does this mean tensile stress would max out at geostationary altitude
where a force equal to the total weight of the cable below it would be felt?

In just a case, would the most likely break point be at geostationalry
orbit, allowing nearly 36,000km of cable to fall down?

Considering the top most portion of the falling cable was going at
9369km/h and that it would further accelerate as it drops altitude,
woudln't there a great big force to pull the whole cable eastward,
causing portions already on ground to drag?

I assume that as more and more cable drags on ground, the drag force
would eventually exceed cable strength and cable would snap, allowing
the still" flyinG" cab;le to move forward some and stary layiong cable
on ground and drag it until that force again exceed the cable strength
(lather, rinse repeat) ?


Would the portions of cable at near geostationary orbit accelerate
enough as it falls that upon reaching entry interface, would burn up?

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#691416

On Jun/19/2018 at 10:12 PM, JF Mezei wrote :
> On 2018-06-19 19:45, Alain Fournier wrote:
> 
> 
>> at first in the rotating reference frame of the ground it is just going
>> down. When you tighten up something that is rotating, like a figure
>> skater pulling in their arms, that increases the rotation rate. So the
>> cable will be going eastward faster than Earth.
> 
> Would such a system be planned with enough "counterweight" above
> geostationary orbit to pull the cable up enough such that its weight at
> altitude 0 would be 0 ?

A little more counterweight than that. You want the cable to be taut.

> Does this mean tensile stress would max out at geostationary altitude
> where a force equal to the total weight of the cable below it would be felt?

The tensile stress has to max out at geostationary altitude. Everything 
higher pulls up, everything lower pulls down. The stress at 
geostationary altitude is a little more than the "weight" of the cable 
below because you want the cable to be taut. That is if you use a 
definition of "weight" that takes into account the centrifugal force, 
that is mass multiplied by local gravitational force minus r 
(pi/953882)^2, where r is the distance to the centre of Earth, the 
pi/953882 part is Earth's rotation (sidereal) rate in radian/s. If you 
compute the "weight" above geostationary altitude (it will be negative, 
the centrifugal force being stronger than gravity) you will get the 
maximal tensile stress (this time you don't have to add a little because 
you want the cable to be taut, the small difference between the forces 
above and below and above geostationary altitude is what keeps the cable 
taut).

> In just a case, would the most likely break point be at geostationalry
> orbit, allowing nearly 36,000km of cable to fall down?

No. The cable is tapered, so it is stronger at geostationary altitude. 
The most likely reason for the cable to break is if it is hit by 
something. The cable being very big at geostationary altitude (and most 
likely multi-stranded) it is probably more likely to survive a hit there.

> Considering the top most portion of the falling cable was going at
> 9369km/h and that it would further accelerate as it drops altitude,
> woudln't there a great big force to pull the whole cable eastward,
> causing portions already on ground to drag?
> 
> I assume that as more and more cable drags on ground, the drag force
> would eventually exceed cable strength and cable would snap, allowing
> the still" flyinG" cab;le to move forward some and stary layiong cable
> on ground and drag it until that force again exceed the cable strength
> (lather, rinse repeat) ?
> 
> 
> Would the portions of cable at near geostationary orbit accelerate
> enough as it falls that upon reaching entry interface, would burn up?

That depends on the physical properties of the cable. We don't know what 
are the physical properties of a cable made of an unknown material. But, 
as I said in another post, I think they would put some kind of mechanism 
to cut the cable in case of an emergency. If you do so only a relatively 
small portion of the cable would fall to the ground.

If you don't cut the cable and most of it comes down, as I said the 
outcome depends on the physical properties of the cable, but burning up 
in the atmosphere seems to me as a reasonable outcome, especially if it 
is multi-stranded. As for dragging and snapping, maybe it would snap at 
or near the attach point to the anchor (where the cable is thinnest) but 
after that, I wouldn't think so. It must be a very strong cable. But 
once again this is just speculation on my part, I don't know how would 
behave a cable of unknown material.


Alain Fournier

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#691414

Alain Fournier <alain245@videotron.ca> wrote on Tue, 19 Jun 2018
19:45:53 -0400:

>On Jun/18/2018 at 11:00 PM, Fred J. McCall wrote :
>> Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
>> 21:06:46 -0400:
>> 
>>>
>>> You put the cable on an east coast.
>>>
>> 
>> Uh, do you mean west coast?  If the thing falls isn't it going to lay
>> out along the direction of spin, which means it falls to the west.
>
>Uh, no I meant east coast.
>
>At least one of the two of us is making a very silly mistake here. 
>

That would be me, although the 'obvious things' you mentioned were no
help at all.

For some reason known only to my tiny mind it was thinking of the
tether structure as having zero tangential velocity.  That meant that
as it fell the Earth would rotate out from under it, leading to a fall
to anti-spinward.

Of course, that's absolutely wrong, since the further up the cable you
go the higher the tangential velocity has to be for the thing to stay
radially 'still'.  That means as it falls the upper portions of the
cable will 'outrun' the surface of the Earth and it will fall to
spinward (to the East), which is what you said.

DOH!


-- 
"Some people get lost in thought because it's such unfamiliar
 territory."
                                      --G. Behn

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#691418

On Jun/20/2018 à 8:13 PM, Fred J. McCall wrote :
> Alain Fournier <alain245@videotron.ca> wrote on Tue, 19 Jun 2018
> 19:45:53 -0400:
> 
>> On Jun/18/2018 at 11:00 PM, Fred J. McCall wrote :
>>> Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
>>> 21:06:46 -0400:
>>>
>>>>
>>>> You put the cable on an east coast.
>>>>
>>>
>>> Uh, do you mean west coast?  If the thing falls isn't it going to lay
>>> out along the direction of spin, which means it falls to the west.
>>
>> Uh, no I meant east coast.
>>
>> At least one of the two of us is making a very silly mistake here.
>>
> 
> That would be me, although the 'obvious things' you mentioned were no
> help at all.
> 
> For some reason known only to my tiny mind it was thinking of the
> tether structure as having zero tangential velocity.  That meant that
> as it fell the Earth would rotate out from under it, leading to a fall
> to anti-spinward.
> 
> Of course, that's absolutely wrong, since the further up the cable you
> go the higher the tangential velocity has to be for the thing to stay
> radially 'still'.  That means as it falls the upper portions of the
> cable will 'outrun' the surface of the Earth and it will fall to
> spinward (to the East), which is what you said.
> 
> DOH!

Ouf! That is an error, but it I can understand making such a mistake. 
 From what you wrote it seemed to me that your reasoning was based on 
Earth spinning westward. I couldn't understand how you could possibly 
had made such a mistake. So I knew something was fishy. I was hoping I 
hadn't forgotten something obvious.


Alain Fournier

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#691438

In article <p2rlid5durbqhpkvqvg6k6psamg0al0bbg@4ax.com>, 
fjmccall@gmail.com says...
> 
> Alain Fournier <alain245@videotron.ca> wrote on Tue, 19 Jun 2018
> 19:45:53 -0400:
> 
> >On Jun/18/2018 at 11:00 PM, Fred J. McCall wrote :
> >> Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
> >> 21:06:46 -0400:
> >> 
> >>>
> >>> You put the cable on an east coast.
> >>>
> >> 
> >> Uh, do you mean west coast?  If the thing falls isn't it going to lay
> >> out along the direction of spin, which means it falls to the west.
> >
> >Uh, no I meant east coast.
> >
> >At least one of the two of us is making a very silly mistake here. 
> >
> 
> That would be me, although the 'obvious things' you mentioned were no
> help at all.
> 
> For some reason known only to my tiny mind it was thinking of the
> tether structure as having zero tangential velocity.  That meant that
> as it fell the Earth would rotate out from under it, leading to a fall
> to anti-spinward.
> 
> Of course, that's absolutely wrong, since the further up the cable you
> go the higher the tangential velocity has to be for the thing to stay
> radially 'still'.  That means as it falls the upper portions of the
> cable will 'outrun' the surface of the Earth and it will fall to
> spinward (to the East), which is what you said.
> 
> DOH!

It's kind of terrifying what the thing does.  And where it breaks has a 
huge impact on what it does as it falls.  

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

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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#691439

On Thursday, June 21, 2018 at 3:27:01 AM UTC-7, Jeff Findley wrote:
> In article <p2rlid5durbqhpkvqvg6k6psamg0al0bbg@4ax.com>, 
> fjmccall@gmail.com says...
> > 
> > Alain Fournier <alain245@videotron.ca> wrote on Tue, 19 Jun 2018
> > 19:45:53 -0400:
> > 
> > >On Jun/18/2018 at 11:00 PM, Fred J. McCall wrote :
> > >> Alain Fournier <alain245@videotron.ca> wrote on Mon, 18 Jun 2018
> > >> 21:06:46 -0400:
> > >> 
> > >>>
> > >>> You put the cable on an east coast.
> > >>>
> > >> 
> > >> Uh, do you mean west coast?  If the thing falls isn't it going to lay
> > >> out along the direction of spin, which means it falls to the west.
> > >
> > >Uh, no I meant east coast.
> > >
> > >At least one of the two of us is making a very silly mistake here. 
> > >
> > 
> > That would be me, although the 'obvious things' you mentioned were no
> > help at all.
> > 
> > For some reason known only to my tiny mind it was thinking of the
> > tether structure as having zero tangential velocity.  That meant that
> > as it fell the Earth would rotate out from under it, leading to a fall
> > to anti-spinward.
> > 
> > Of course, that's absolutely wrong, since the further up the cable you
> > go the higher the tangential velocity has to be for the thing to stay
> > radially 'still'.  That means as it falls the upper portions of the
> > cable will 'outrun' the surface of the Earth and it will fall to
> > spinward (to the East), which is what you said.
> > 
> > DOH!
> 
> It's kind of terrifying what the thing does.  And where it breaks has a 
> huge impact on what it does as it falls.  
> 
> http://gassend.net/spaceelevator/breaks/index.html
> 
> Jeff
> -- 
> All opinions posted by me on Usenet News are mine, and mine alone.  
> These posts do not reflect the opinions of my family, friends, 
> employer, or any organization that I am a member of.



Just some names Steve "Steven Petruzzellis" Carroll has used
    "Evil" John *
    "Evil" Snit *
    Big Crotch on a Small Fish
    Cornelius Munshower
    CSMA Moderator
    Edward Stanfield
    Fretwiz *
    Hitman Hero
    Measles
    Petruzzellis Kids
    Sigmond
    Slaveen
    Smit
    Steve C *
    Steve Camoll *
    Steve Carroll <noone@xxxxxxxxxxx> *
    Steve Carroll <stevecarroll@xxxxxxxxxxx> *
    Steve Carroll <trollkiller@xxxxxx> *
    Steve Carroll's Dog *
    Steve Carrolll *
    Steve Carrroll *
    Yevette Owens
    Yobo_Obyo
Turns out Scout's constant mentioning of Snit met the agreed on criteria of trolling, so he abandoned that, too. Now that nobody is talking to Scout, he's making it sound like he's figured out the right timing -- when in fact, people are just finally wisening up to his crap. Fool! 

It's like a spam message. Scout has already decided what he is going to say before he calls. What you say is irrelevant. What Snit says is beside the point. The advocates insist searching for guidance for a Linux application is trolling. 

Until Scout offers up his 'superior' Windows workflow for testing, there is no challenge, just insane assertions. All that he cares about is that Scout gets to deal out his automated call and then hang up and giggle about it. The fact that Snit is a real person on the other end of the phone is the game. 

--
Eight things to never feed your dog
http://www.5z8.info/facebook-of-sex_w4l4wg_bomb
https://www.youtube.com/watch?v=IhOfBmWwCVY
http://www.5z8.info/hackwebcam_e9z2tw_friendster-of-sex
Jonas Eklundh

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#691449

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 ?

Why would it break up in space as it falls?

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#691501

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

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#691520

On 6/21/2018 7:57 PM, 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

Alains idea to make a "space elevator" out of al dente spehetti is an
amazing idea.   Who bring the meat ball ?

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#691542

In article <ilRWC.464537$nq5.135927@fx36.iad>, 
jfmezei.spamnot@vaxination.ca says...
> 
> 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 ?

Because it's flexible, duh.  Imagine that you took 10 meters of fishing 
line with a weight at the bottom then cut it in the middle.  Would it 
stay straight as it fell?  Try it!

I majored in dynamics and control at Purdue.  This stuff is *not* 
intuitive, but it can be simulated and verified experimentally.  

> 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 ?
> 
> Why would it break up in space as it falls?

To put it simply, it breaks when the stress at a point exceeds the 
material strength.  Again, the dynamics of the falling tether is not 
intuitive.  That's why we perform simulations like this. 

Why did the Tacoma Narrows Bridge break up due to *wind*?

https://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)

https://www.youtube.com/watch?v=j-zczJXSxnw

Again, this stuff isn't intuitive.  The bridge designers, at the time, 
simply didn't take into account the dynamics of the bridge in a strong 
wind.  

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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