Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_763.TXT

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Subject: SPACE Digest V13 #763

SPACE Digest                                     Volume 13 : Issue 763

Today's Topics:
            Re: Beanstalk analysis reprise
              Re: Fred's Operatic Death
             Re: Access to Space
                 Re: NASA CDs
             Re: Access to Space
              Re: anti-gravity?

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

----------------------------------------------------------------------

Date: 17 Jun 91 17:39:16 GMT
From: cis.ohio-state.edu!magnus.acs.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!ox.com!fmsrl7![e-mail]  (Ron Carter)
Subject: Re: Beanstalk analysis reprise

In article <[e-mail]>, w-dnes.guild.org!waltdnes
 (Walter Dnes) of "Ye Greate Calkulatinge Machine Hoaxe" writes:
>[e-mail] (Ron Carter) writes:
>     TV transmitters and microwave relay towers aren't *DESIGNED*
>to "do work on the air" (pun not intended). Yet occasional
>failures/collapses do happen.

Because loads on the structure exceed its strength.  However,
you've not shown a single calculation to test the proposition
that this is likely in the case of a beanstalk.

Why not?  Is expressing your ignorance your best tactic?

>     In the general case, you will *NOT* find wind blowing at the
>same direction and speed from ground level to the top of the
>stratosphere. Wind at 10,000 feet can be one speed and direction,
>another at 20,000 feet and yet another at 30,000 feet, etc.

Wonderful.  The smaller the net force on the beanstalk, the
smaller the net offset it will assume from vertical.  The
worst-case situation is all winds in the same direction.

>>Any flex in the beanstalk, or vehicles moving up and down,
>>will cause it to shed ice.  Also, it can be heated electrically
>>if icing is a difficulty.
>
>     Structural icing simply makes loading worse. It adds weight
>to the whole structure, and increases the cross-section area that
>the wind sees. Don't expect heating elements to keep the
>beanstalk 100% ice-free 100% of the time. If it's hot enough to
>do so, I'd hate to see what it does to the graphite beanstalk
>itself.

Of course, you didn't bother to consider the possibility of
thermostatic control.  Nor did you calculate the power required
to keep ice thickness to less than some arbitrary value.  Graphite
is very refractory; it gets stronger with increasing temperature.

Again, the argument from ignorance:  "If I don't know that
it won't be a problem without doing any work to see if it
might not be, it is."  Very poor technique.

> Heavy rime icing in cloud is a lot worse than the worst
>freezing-rainstorm you have ever seen. It is one of the worst
>nightmares for a pilot.

Don't tell me about pilot's nightmares.  I've lived a few.

>A falling
>beanstalk can wrap around most of the equator and cause damage in
>lots of countries.

Not unless it breaks far, far above the surface.  The portion of
the beanstalk above the break remains in orbit; only the portion
below will fall anywhere.  If the portion below is large enough,
breaking it further will allow the upper parts of that to remain
in orbit as well.

The terminal velocity of a cable of density 1.7 must be
considered.  If the cable is only an inch or two in diameter
and the lengths are not long enough to whip the ends up to
high speed ("range-safety" equipment is indicated!), terminal
velocity will not be high, and damage will be small.

>     Electrical heating is one anti-icing system. You'd need
>power fed from the surface up to a height of 10 - 15 km. A couple
>of insulated cables power to worry about. What does this do to
>the weight of the whole system ?

Why didn't you calculate this yourself?  Are you incapable?
How do you know it is an issue at all?

>Does the whole beanstalk need to be made thicker ? How much ?

Why didn't you calculate this yourself?  Are you incapable?
How do you know it is an issue at all?

>Your other alternatives are to pump
>de-icing fluid several km uphill against gravity, or encase
>several km of the beanstalk in a flexible airtight sleeve (in
>short manageable sections) and inflate/deflate it in cycles to
>dislodge icing as it accumulates. Those are the three main types
>of anti-icing systems used on aircraft.

Of course, you never considered systems not in use on aircraft.
Alternatives include piezoelectric flexors to deform the beanstalk's
cross-section and flake ice off, flash heaters to evaporate ice into
steam and blow overlying ice off, and other devices not compatible
with bent sheet metal structures.  Use some imagination!

>     In summary, wind and ice loading is an important real world
>problem that no amount of hand-waving will make go away.

Again, how do you know it is an issue at all?  Have you calculated
the loadings and found them excessive, or are you just hand-waving?

>     As far as weight is concerned, I would be much more worried
>about the weight of several km of heating cable wrapped around
>near the bottom of the beanstalk.

How much cable do you need?  If you don't know, how do you know
it is an issue?

>     The thread title says "Beanstalk reprise".

Beanstalks are a class of tether.  Weren't you here for the lecture?

>     More to the point is... 40,000 km worth of the stuff put
>together as one piece.

Ever consider that it might NOT be one piece?  That it might have
joints and connectors?  That individual strands might be testable
and replacable while in use, like a suspension bridge?  Where's
your imagination?

>     Beanstalks aren't possible given today's technology. I
>agree with you... again !!

Agreed.  However, they are possible given MATERIALS known
today.  This is a crucial distinction; we know what to shoot
for, and even many of the physical processes required.

As for ice loading and wind loading, I'm not going to lecture
for free to address your misconceptions any longer.  If you
want to continue responding to my data with hand-waving, you
can pay for the priviledge.  Ergo, I offer you this deal.
I bet that I can do the following:

1.)    Refute the contention that ice loading on a beanstalk
    of design chosen by me (within reason) presents any
    structural difficulties, given the use of known de-icing
    technology, and

2.)    Refute the contention that wind loading at a wind speed
    of 250 KPH could bring a beanstalk of design chosen by
    me (within reason) down, given ice loads limited by
    de-icing equipment a la 1.) above.

I assume that you will bet that I cannot refute these contentions.
I offer the sum of $100 American on each of these two assertions.
We must agree on a judge.  This has advantages for you:  you get
the lecture, and YOU get paid if it is wrong.  You only have to
lay out money if you are truly getting educated.  What a deal!

So, are you ready to put your money where your mouth is?

------------------------------

Date: 18 Jun 91 05:15:21 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!ub!galileo.cc.rochester.edu!rochester![e-mail]  (Brian Yamauchi)
Subject: Re: Fred's Operatic Death

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]> [e-mail] (Doug Mohney) writes:

[ referring to a post from a JSC employee ]

>>He pays taxes too.

>From his paycheck which is 100% funded by the IRS, he pays perhaps
>30% back to the IRS.  BFD.  I said his pro-astronaut posts were
>"self-serving" and they are; they serve to provide revenue for the
>paychecks of himself, his boss, and his co-workers at JSC.  The same cannot
>be said for my postings.  My employer sells computers to voluntary
>purchasers. I do not derive revenue from any of the subjects discussed.

>Of course he has a right to his self-serving propaganda; I also have
>a right to point it out for what it is.

You assume that he's supporting the manned space program because he
works for NASA.  Have you considered that the converse may be true?
Perhaps he works for NASA because he believes in the manned space
program.

Whether he's right or not is a completely different issue, but I think
it's unfair to denigrate all pro-NASA posts from NASA employees as
"self-serving propaganda."

Usenet is not (yet) a major focus of political power in this country.
Most people who post to the net do not believe their posts will have a
major effect on national policy.  I believe that NASA employees who
post their opinions are simply expressing their personal views and not
attempting Machiavellian political maneuvers.

While I think it would be senseless to accept their opinions as fact
simply because "they're the experts", I think it's equally senseless
to discard their opinions as propaganda simply because "they're paid
by the IRS".  Their arguments, like anyone else's, should be weighed
on the merits of the views expressed, and not upon the identity of the
poster's employer.
--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Department of Computer Science
_______________________________________________________________________________

------------------------------

Date: 18 Jun 91 17:27:19 GMT
From: sequent!muncher.sequent.com![e-mail]
Subject: Re: Access to Space

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>Communications satellites are a pretty loose defintion of 'industry'; I
>am not terribly impressed by an example that uses passive objects in high
>orbit that do little more than bounce and amplify signals sent from the
>ground.

Interesting.  This ("loosely" defined :-) self-sustaining industry is $6
billion per year. The proposed El Dorado platinum mining would be $3
billion per year.  CNN, MTV, News Corp., TV network communications, direct
broadcast TV and radio, Ted Turner, Rupert Murdoch, international telephone
calls, data communications, wire services, the international legs of
USENET, etc.  Not terribly impressive.

Now that's special.


--
Nick Szabo            [e-mail]
Embrace Change...  Keep the Values...  Hold Dear the Laughter...
These views are my own, and do not represent any organization.

------------------------------

Date: 18 Jun 91 17:39:48 GMT
From: fluke![e-mail]  (Jim Adams)
Subject: Re: NASA CDs

In article <[e-mail]> [e-mail] (Mike M. Miskulin) writes:
>Does anybody have information on how to obtain CDroms of the Voyager, Viking
>and other space missions from NASA?
>
>Thanks.
>
>Mike
>[e-mail]

Try the University of Colorado Laboratory for Atmospheric and Space
Physics.  Their phone number is 303-492-7666 (FAX [phone]).

They offer a two-disk set for $25 called "Space Science Samplers"
which include 800 images of Uranus from Voyager 2, and 1,400 files of
space and earth science data.

In addition, they offer a 12-disk set that includes the above sampler
and ten volumes (CDs) containing something like 20,000 Voyager images
of Jupiter, Saturn, Uranus, and Neptune.  The cost of the full set is
$120.

Included in each of the sets is your choice of Mac or PC image
retrieval software.

I believe this is what you're looking for.  It's the deal of the
century.

If you want to order this minute, send your check to:

    University of Colorado
    Laboratory for Atmospheric and Space Physics
    Space Science CD ROMs
    Campus Box 392
    Boulder, CO 80309

    ATTN: RANDY DAVIS

Have fun.
--
James F. Adams       John Fluke Mfg. Co., Inc.        Everett, Washington USA
WORLD:[e-mail]
UUCP:{ihnp4!uw-beaver,ucbvax!lbl-csam,allegra,decvax!microsoft}!fluke!jfadams

------------------------------

Date: 18 Jun 91 19:57:48 GMT
From: sequent!muncher.sequent.com![e-mail]
Subject: Re: Access to Space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:

>[Satellite communications] is a big industry but it is by no means
>self-sustaining. Buyers of launch services only pay the incrimental cost
>of their launches.  They use huge amounts of infrastructure provided by
>nasty central planners (some of it constructed to support evil manned
>space).

Oh boy, now we're down to "good vs. evil".  So who is Darth Vader here?
The TV networks and telephone companies using those evil robotic
communications satellites?  Or perhaps the people watching the TV
or making the phone calls?  May the Force be with you.  :-)

Seriously, my goal is and always has been to create an economical, self-
sustaining manned infrastructure in space.  I am afraid that the
solution is a bit more subtle and long-term than launching tin cans into LEO
that cost 2,000,000 times what it costs to build a house on Earth, without
producing any significant revenues.  That is not economical.  That is not
self-sustaining.  It is not even close.

The U.S. commercial launch vehicles use USAF launch pads developed for
the DoD automated infrastructure (which is also, sadly, self-sustaining,
insofar as there are still Saddam Husseins and Soviets with thousands of
nuclear tipped ICBMs and other assorted hazards on our planet).   The
automated launchers were themselves developed from automated ICBMs
(Thor, Atlas, Titan).   For the European launch service, both the launch
pad and the automated Ariane rocket were built from scratch to launch
automated commercial payloads.  The amount of Apollo and Shuttle
infrastructure used by the satcom industry is practically nil, despite
the $100's of billions NASA has spent on it.


--
Nick Szabo            [e-mail]
Embrace Change...  Keep the Values...  Hold Dear the Laughter...
These views are my own, and do not represent any organization.

------------------------------

Date: 18 Jun 91 21:22:21 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!ais.org![e-mail]  (Tony Poole)
Subject: Re: anti-gravity?

[e-mail] (Brett Kottmann) writes:


>    A researcher in Scotland has developed a device that harnesses
>gyroscopic energy to lift a device against gravity--antigravity for all intents
>and purposes.

>    The inventor has built several machines with the following
>configuration:


>        [] - small engine to power flywheels
>              ------
>           |  |    - flywheels mounted so that their spin up-down
>           ----  - bottom of apparatus (central rod about which flywheels

>would rotate if allowed)

>    In demonstrations, the apparatus lifts against gravity (it is balanced
>beforehand with an equal weight via balance arm).

>    The inventor claims that the tendency for the flywheel arms to move
>outward (centrifigal force) is greater than the force trying to move the
>flywheels inward.
>    Thus the machine "pushes" against gravity.

Hmmmmm.......

Seems to me those same flywheels that "push" against gravity will work
with gravity at 180 degrees flywheel rotation.

Of course, if you had some sort of weight that were extended out at
a bigger radius on the downward rotation and retracted on the upward...
Nah...that's too easy.....

You sure maybe he not powering it with cold fusion from a dishpan?? :-)

------------------------------

End of SPACE Digest V13 #763
*******************