Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_773.TXT

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Subject: SPACE Digest V13 #773

SPACE Digest                                     Volume 13 : Issue 773

Today's Topics:
             Space Exploration Initiative
            Re: Beanstalk analysis reprise
     Re: On the Non-Anticipation of Automated Spacecraft
      Re: Fred's Operatic Death (actually about Nick's postings)
             Re: Mining El Dorado
             Re: == No Subject ==
                 Re: The USF
            SPACE Digest V13 #639

Administrivia:

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Date: 20 Jun 91 07:01:35 GMT
From: ogicse!milton!hardy.u.washington.edu![e-mail]  (Brett Vansteenwyk)
Organization: University of Washington, Seattle
Subject: Space Exploration Initiative
Sender: [e-mail]
To: [e-mail]

Got a big, thick, and glossy in the mail the other day titled "America's
Space Exploration Initiative".  I do not know if this report has already
been thoroughly hashed out on this newsgroup (having missed some periods
of traffic), but if there is a consensus I will try to summarize bits and
pieces of it on the net (hopefully I will not infringe on any copyrights
and that NASA/government would like this report distributed as widely as
possible in any way it can).

What stood out in my mind was the return to favor of 2 rocket engines--
nuclear based propulsion and the F-1 engine.  What was doubly intriguing
was that a souped up version of the F-1 was developed (1.8M lbs of thrust
vs the garden variety 1.5M) before the whole system was put on a shelf.
The F-1 would become the first stage engine (both main booster and strap-ons)
for a 150Klb to 250Klb class heavy lift booster.

The nuclear engine has the advantage of a greater specific impulse--making
it much more viable for a trip to Mars.  I think that people in the space
policy area finally said the hell with the fears of segments of our society
because of the large advantages of this type of system.

Overall my impression is that this is a document produced by people who wanted
to dream just a little in the face of the current crises in this arena.

I promise to avoid interjecting opinions into these possible summaries (after
this post!)  Please let me know if these summaries are desired.

                --Brett Van Steenwyk

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

Date: 20 Jun 91 15:34:18 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!ox.com!fmsrl7![e-mail]  (Ron Carter)
Subject: Re: Beanstalk analysis reprise

Mr. Lydick, please do not post several nearly identical articles.

In article <[e-mail]> [e-mail] writes:
>I don't think I've heard of any beanstalk proposal that has a cable "only an
>inch or two in diameter".

Consider one proposed.  It is the worst-case for icing and wind load,
but it still appears practical.  For safety considerations in the event
of a break, a beanstalk might be designed to separate into strands, each
a fraction of an inch in diameter, terminal velocity minimal.

>On another note:  A couple of years ago, somebody (Robert Forward, maybe?)
>published a fairly detailed study of what it would take to make a beanstalk in
>a fact article in Analog Science Fiction/Science Fact.  As I recall, the
>conclusion was that if our knowledge of how chemical bonds work is correct,
>there is theoretically no material strong enough for a beanstalk anchored to
>the Earth (to Mars or the Moon, yes; to the Earth, no), but that pinwheels
>would be possible.  Anybody out there with that issue of Analog?

Check my article <[e-mail]> (which began this thread) and
go over the math and the references for yourself.  Unless I have
made a serious mistake, the conclusion above is wrong.  Graphite
whisker is proof-by-existence that chemical bonds are strong enough.

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

Date: 20 Jun 91 15:19:59 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Kieran A. Carroll)
Subject: Re: On the Non-Anticipation of Automated Spacecraft

In article <[e-mail]> [e-mail] (Loren Petrich) writes:
>
... The only maintenance problem that
>remains for most satellites is the question of maneuvering propellant.
>
Wrong. Solar cells degrade severely in the space environment.
End-of-life power is substantially less than beginning-of life power.
The phrase itself (common among spacecraft designers) is indicative --
solar arrays have a "lifetime", after which they're no longer
of much use.

Solid-state electronic components do fail, as well. The probability
of failure of any given component in a spacecraft, over its design
lifetime, may be very small. However, the sheer number of components
in modern communications satellites (for example) is so large that
several are almost sure to fail within ten years or so.

Thermal control paints are a significant component of many spacecraft
thermal control subsystems. These paints (particularly white paint)
degrades with exposure to sunlight and radiation, so that after
a few years its absorptivity and emissivity can change substantially.

The net result is that making a spacecraft survive longer than
five or ten years is very difficult. The usual approach is to
over-design solar arrays (to provide more power than is needed
at beginning-of-life), to add redundancy to electronic designs
(to deal with the inevitable failure of some of the components),
and to add additional thermal-control devices (e.g. design the
spacecraft to be "too cold" at beginning of life, by having
more white paint than nominal, then compensate by adding heaters,
utilizing some of the excess beginning-of-lide solar array power;
as the years go by, the white paint becomes less effective at
rejecting heat, allowing you to turn the heaters off).

My point is that there are various modes of spacecraft aging,
that could be compensated for by on-orbit refurbishment. These
include re-fueling, replacement of solar arrays, replacement
of thermal-control surace materials (or re-painting, perhaps?),
and change-out of failed electronics (or pre-emptive replacement
of "old" boxes, even if they haven't yet failed). The lack of on-orbit
refurbishment increases the mass and design cost of current spacecraft,
and puts a limit on their lifetime.
--

     Kieran A. Carroll @ U of Toronto Aerospace Institute
     uunet!attcan!utzoo!kcarroll [e-mail]

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

Date: 20 Jun 91 21:56:25 GMT
From: sequent!muncher.sequent.com![e-mail]
Subject: Re: Fred's Operatic Death (actually about Nick's postings)

In article <[e-mail]> [e-mail] (Mary Shafer) writes:
>
>Nick has informed me that "Public employees slandering [him] on the
>net are cruising for a bruising."
>

I find it interesting how Nick can dish it out, but can't take it himself.

Some of my favorite subject threads from Nick are his accusation of lying by
NASA management on program costs, the labeling of the membership of the
Synthesis Group as "dominated by Apollo-era astronauts and engineers", and
how Sequent would lose half its revenues without comsat delivered phone
service.

Nick has accused NASA management of lying about the costs of the shuttle and
space station.  The only evidence he provides to back these claims were the
escalating program estimates and costs.  By Nick's definition of lying we
can find some very interesting guilty parties:

In manned space we find ESA has been lying about the cost of Hermes
since the current estimate is 30% over the original target budget.  Closer
to home, we must assume that Nick thinks the management of Sequent must be a
bunch of liars since their public financial projections have been wrong the
last few quarters.  Certainly if NASA is expected to get multiyear estimates
correct, what does that say about incorrect quarterly estimates?

At a lower level yet, all the engineering project managers at Sequent and at
every other leading edge engineering company must have been lying when they
made their original project budgets and schedules.  What else could it be
when the project inevitably came in late and/or over budget.

On the issue of the makeup of the Synthesis Group, I suggest Nick should
take his own advice and read AW&ST.  In the June 17 issue the editors say:
"He (Stafford) assembled a truly distinguished panel whose members did an
admirable job of sifting more than 2,500 proposals, ideas and suggestions
from the U.S. government, industry, academia and interested individuals."

I assume one or more of those submissions were yours Nick.  I'm sure the
former USAF generals and AW&ST editor who were on the panel would fit Nick's
"Apollo-era astronaut and engineers" label.

The statement that Sequent would loose half its revenues without comsats is
going to be a little hard to substantiate Nick.  If there was no phone service,
couriers could replace fax machines, and at a cheaper cost for large documents.
But what you ignore is transoceanic telephone cable.  Voice can still get to
Europe without comsats.  As reported in the trade press, many service
providers are headed away from comsats to fiber-based cable for
point-to-point communication because fiber's life cycle cost vs. bandwidth is
better than comsats.

Maybe what we need is sci.space.nick so Nick can go play with himself there,
and leave sci.space for the rest of us.  That would also put Nick on equal
footing with the US manned space program by having his own subgroup; just
like the shuttle.  And with 93 out of the last 700 sci.space articles authored
by Nick, the volume is certainly there to support a new newsgroup.

John Theus         [e-mail]
President
The Theus Group

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

Date: 21 Jun 91 00:37:45 GMT
From: hub.ucsb.edu!ucsbuxa![e-mail]  (Charles Frank Radley)
Subject: Re: Mining El Dorado



Ahem, It has been pointed out to me that nukes would make the
asteroid ore radioactive, and thus essentialloy useless for most applications,
certainly those involving manned presence, and won't help electronic
applications.
   I think I have decided I prefer conventiopnal explosives.

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

Date: 21 Jun 91 10:06:49 GMT
From: mcsun!ukc!strath-cs!str-va![e-mail]  (Theora Jones, In Person!)
Subject: Re: == No Subject ==

>> #In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>> #
>> ##The only manmade structure that can be seen with the naked eye from
>> space,
>> ##the Great Wall of China, has been around for a fair amount of time
>> in
>> #.......
>> #
>> >BZZZT...Wrong. TONS of stuff is visible from LEO. Do you think that
>> >Manhattan or LA suddenly become invisible because you are 120 miles
>> >up? Perhaps the Great Wall is the only object visible from the Moon
>> or
>> >somesuch distance.
>> >
>> BZZZZZT,BZZZZZZT WRONG WRONG WRONG.  8^)
>>
>>         The Great Wall of China is the only thing visible from space
>>         with
>>                 "the naked eye."
>
 I would have thought that you wouldn't see much in space with "the naked eye"
seeing as you would be much too busy boiling in the vacuum. unless of course
you mean from within a space ship/suit when it isn't really the naked eye is it
:)

really, though I would imagine that just about everything (cities, major
transport routes, large constructions, lighted areas etc) would be visible from
LEO....

       Theora.

--
sig (made it through the ethernet alive!)
================================================================================
Theora Jones  Strathclyde University, SCOTLAND   || " I can fly higher than an
[e-mail] (somewhere on JANET)    ||   Eagle, with you as the
CABP10%vaxa.strath.ac.uk (elsewhere, hopefully)  ||   wind beneath my wings "
CABP10%vaxa.strath.ac.uk@ukacrl (just might work)||                 8:-) 1990
A solution to the worlds problems: Kei and Yuri! ||      "Lets be MAWS!"-DP3.2
================================================================================

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

Date: 21 Jun 91 18:09:44 GMT
From: agate!spool.mu.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!groucho![e-mail]  (Sheaf)
Subject: Re: The USF

In article <[e-mail]> [e-mail] writes:
>Disclaimer: (Yes, at the top):  I am not associated with the USF in any
>way, nor do I necessarily support its activities.  But ...
>
>I don't believe anything that the USF ever posted ever implied that it
>was going to be passing laws regulating space activities, much less
>enforcing them.  One of its stated goals is to HAVE an international
>space agency (ISA) by 1993, not to BE the international space agency by
>1993.  Clearly foreign governments would never submit legislative

    [stuff deleted]
>
>However, I don't see anything inherently wrong with being a small
>organization trying to sound big in order to get big.  Small businesses
>use the tactic all the time.
>

Just a tip, Conrad, but I wouldn't go around using business as a way to
justify an ethical question.  The point is not the size of the USF, but
it legitimacy, and whether any organization, legitimate or not, should
be filling up the newsgroup with rhetoric that is has no apparent means
of doing anything about.  If you want to use business as an example, I
think the issue is not of a small business trying to pass itself off as
a big one, but more like, say, an unauthorized servicer of some product
trying to pass itself off as an authorized one.  Its dishonest either way
to not be totally open with your prospective members or clients
about the expertise, influence, and resources of your organization.

Now, for example, the poster of the USF items (Dobson ?) not only seems
unwilling to discuss these sorts of items, but has intentionally or
unintentionally passed himself off as being somehow associated with
Cornell Univ., which he apparently holds no influential position at.
Right off the bat I'm skeptical.  I think what the previous posters
meant about the danger of something like this is the fact that an
organization that succeeds in making itself more important than it
is, could conceiveably carry a much bigger influence with people who
don't know any better, than it deserves.  Look at all the political
lobbys in the US... they claim to represtent the support of huge
numbers of people, and the politicians do believe them... but most
really only represent a very small special interest.

It's one thing to suggest an idea for starting a civilian space group,
but it's quite another to try to convince everyone that it already exists.
If the USF/Dobson? would just start a normal dialog and be straightforward
about its resources, maybe they'd get a little more support.

S. Sheaffer

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

ReSent-Message-ID: <Added.scMbl=[e-mail]>
Resent-Date:  Fri, 21 Jun 91 18:08:08 EDT
Resent-From: Tom McWilliams <[e-mail]>
Resent-To: [e-mail]
Date:         Fri, 14 Jun 1991 02:49:15 TZONE
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #639
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>

Re: The Un-Plan

>Keep in mind that even an impact on the Moon or Mars of an
>asteroid would create enough flux, for a few minutes, to ignite
>flammable material in the Earth's biosphere.

You're Nuts!   Mars?  It's about 3/4 as far away as the sun (at it's closest)
which means it would need to radiate 9/16 times as much as the sun, just to
equal the sun's heat, let alone exceed it (since the sun does not ignite
things on earth).  I don't even need to do a Back-of-the-envelope calculation
to know it's impossible.  The Moon?  Well, ok.  it's POSSIBLE.  But I also
don't need a B_O_T_E_C to know that the impacting object would have to be
many mag's more massive than any object we'd ever try moving around the
solar system, let alone be able to move around.  We'd just mine it where
it is!

>> * Solar Power Satellites, built from asteroid materials.

>Due to the probability of our achieving economical fusion in the near
>future, I seriously doubt SPS will ever be important.

Youv'e mixed your "probably" 's  with your "will" 's.   tsk tsk.  Fusion has
'probably' been in our future for 30 years now.  "It doesn't feel far away".

Nevertheless, you've left out on important point;

SPS _is_ fusion.

It does have some VERY attractive advantages to the planet-bould fusion
that you are thinking of.
1) You don't have to mine, process, or re-load the fuel.
2) You don't have to worry about the pile's stability (for a few G-Years)
3) You don't need a container, waste dump, people, etc.

Why go to all the trouble to build a fusion generator, when we can use the
one that has been placed at the convienient distance of 150,000,000 km from
the planet?

Tom
Acknowledge-To: <18084TM@MSU>

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

End of SPACE Digest V13 #773
*******************