Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no136.txt

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Date: Sat, 22 Aug 92 05:02:00
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #136
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 22 Aug 92       Volume 15 : Issue 136

Today's Topics:
                          Apollo Video Clips
                       Asteroid report (2 msgs)
            BuckyStalks (was Re: Beanstalks in Nevada Sky)
              Energya and Freedom and Soyuz ACRV and...
                Inflatable Space Stations - Why Not ?
                           Opinions on NLS
                        Private space ventures
                               Tethers
   Viable alternatives to space? Was ( Re: Private Space Ventures)
                       What happened to Viking?
         With telepresence, who needs people in Earth orbit?

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

Date: 18 Aug 92 17:46:54 GMT
From: Mike Schatz <[e-mail]>
Subject: Apollo Video Clips
Newsgroups: sci.space

Does anyone know where I might obtain the video clip from one of the
Apollo lunar landing missions where an astronaut dropped a
feather and a hammer simultaneously? (I would like to show this to
a physics class I'm teaching this fall--it's a nice illustration of
the Law of Universal Gravitation)

Thanks

Mike

[e-mail]

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

Date: Fri, 21 Aug 92 23:34:00 EDT
From: Thierry Lach <curlie!thierry>
Subject: Asteroid report
Newsgroups: sci.space

[e-mail] (Forrie Aldrich) writes:

> Recently, and associate mentioned there was a report of a rather large
> asteroid (or some object) approaching or within our solar system, and
> with a trajectory currently in our direction.  And that radio signals
> have been transmitted from said object.
>
> This does sound a little out-of-the-ordinary, can someone confirm or
> deny this? (for those familar with Arthur C. Clark, the above reference
> makes me have visions of RAMA heading our way... ::wince:: ;)
>
> Thank you.
>
> --
>        -----------          Forrest Aldrich          -----------
>        -------     morwyn![e-mail]      -------
>        ----                             ----
>        --         VISION GRAPHICS --    Dover, NH - USA           --
>        ------------------------------------------------------

or maybe Niven and Pournelle (_Footfall_) ?

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

Date: 22 Aug 92 04:54:30 GMT
From: Dave Tholen <[e-mail]>
Subject: Asteroid report
Newsgroups: sci.space

Forrie Aldrich writes:

> Recently, and associate mentioned there was a report of a rather large
> asteroid (or some object) approaching or within our solar system, and
> with a trajectory currently in our direction.  And that radio signals
> have been transmitted from said object.
>
> This does sound a little out-of-the-ordinary, can someone confirm or
> deny this? (for those familar with Arthur C. Clark, the above reference
> makes me have visions of RAMA heading our way... ::wince:: ;)

Probably was referring to the close approach of 4179 Toutatis on December
8.  The radio signals coming from it will be the radar waves bounced off
of it by Steve Ostro.  It (nor any other asteroid) has transmitted anything
to Earth all by itself.

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

Date: 22 Aug 92 03:02:34 GMT
From: William Lewis <[e-mail]>
Subject: BuckyStalks (was Re: Beanstalks in Nevada Sky)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Suppose we came up with a (Buckytube-based) material strong enough to
>make an Earth beanstalk, and it could be manufactured in mega-kilo lots
>for pennies per kilo.  How could we use it to get into space?  Is there
>any small-scale, bootstrapping approach that avoids involvement with
>Big Dump Organizations like NASA and the US Govt.?

  The big problem with synchronous tethers (besides the sheer amount
of material) is probably building them. This is essentially a
22,000-MILE high version of the "Indian rope trick"; the only
proposals I've ever seen have been vague mumblings about capturing
an appropriately-composed asteroid or comet-piece into geosynchronous
orbit and manufacturing the tether there, lowering it as it's built
(simultaneously moving the rock-and-factory's orbit outwards, of
course).  This is definitely not a bootstrappable activity; you have
to get a whole industry into orbit before you get *any* return
in the form of a usable tether.


>OK, suppose we had that material AND Cold Fusion producing kilowatts
>per cc. ...

  Well, why didn't you SAY so?!? We could build the tether around a
temporary Lofstrom loop. Or, we could build the tether on the ground,
laid out flat (we'll rent the Equator) and put it in orbit via repulsion
against the Earth's magnetic field. =8) =8) =8)

---
Seriously, since I'm posting this anyway, does anyone know of any
cleverer (or at least easier) ways to get a beanstalk built than
the extrude-it-from-Geosynch approach? Specifically, anything that would
let us keep the factory on the ground?


--
email: [e-mail]             |  Home:  Seattle, Washington   |
     (William Lewis)                     |  47 41' 15" N   122 42' 58" W |
NeXTmail: [e-mail] `-------------------------------'
        --*-- Member, Coalition to Preserve Semantic Vacuity --*--

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

Date: 22 Aug 92 04:46:39 GMT
From: Mike Santangelo <[e-mail]>
Subject: Energya and Freedom and Soyuz ACRV and...
Newsgroups: sci.space

[e-mail] (Allen W. Sherzer) writes:

>In article <[e-mail]> [e-mail] (Gary Coffman) writes:

>>Indeed. If we follow the plan of using Soyuz and HL Deltas, the Shuttle
>>fleet is *gone*.

>OK, I have posted extensive numbers on the alternatives. Let's see some
>numbers from you. What will the Shuttle do that will not only justify the huge
>expense of keeping it but also pay for the opportunity cost of the cheaper
>infrastructure?

>I await your reply.

>>With this plan 3/4 of the
>>Shuttle fleet is available for other work than servicing Fred.

>Shuttle flies about eight times a year (at least it has for the last
>2 years and looks like it will do so this year). Since using Shuttle
>as the ACRV will about half the number of flights there will be NO
>non station shuttle flights.

>Thus we will be spending $5 billion each and every year to resuply the
>station. That's an interesting number since you could build the
>Porche of ACRV's for that and could do ALL your tasks for 20% of that
>figure.

>>As to the $65 million firm price for Soyuz, I've posted about this
>>several times.

>1. That is about three times the price I have seen for a Soyuz. I am
>assuming $100M per Atlas/Soyuz launch even though the actual cost will
>likely be much closer to $75 million.

>2. We are stuck with Soyuz anyway since we won't get an ACRV.

Probably true, but I will remain skeptical about its inclusion
into Fred's support infrastructure until I see it go up, and
probably remain that way until someone/some people come down in
one (one would hope as a dry run and not due to a real emergency).

>3. Lots can be done to mitigate this. We can sign long term contracts,
>build in the US under licence, or a number of other alternatives.

What do you think the tooling cost is going to be to make them?
Russian fabrication <> american, I would think this would be
non-trivial in terms of start-up time.  Once american workers are
put to the task with big aerospace contractors to manage them you
can probably bet that the Soyuz manufacture is going to get pretty
uncomptetive pretty quickly, especially if you factor in start-up
and tooling costs.  I would also assume this would take quite a few years
before the first american produced Soyuz rolls off the line.

No, I think we should let the Russians keep making them, labor
costs are bound to stay low at least in the near term, also
give them something to do and some hard currency.

Geez I hope they (the Russians) spend ALOT of time making all
the instrumentation readable (clearly, well translated) in English.
Including all the needed documentation.

How would these systems be certified in the US?

Has anyone given thought to training logistics with regard to
piloting the things?  Would they take place in Russia or the US?
I take it this is factored into the overall cost?

I've been reading this thread for sometime and really hadn't
seen any of the last several topics discussed.  Just seems kinda
'assumed'.

--
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Michael F. Santangelo                 + Internet: [e-mail]
Computer & Network Systems Admin      +           [e-mail]
CBL / CEES (Solomons Island)          +           [e-mail]

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

Date: 21 Aug 92 23:50:03 GMT
From: [e-mail]
Subject: Inflatable Space Stations - Why Not ?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Rui Sousa) writes:
> In article <[e-mail]> [e-mail] writes:
>
>>    Whatever became of the idea of inflatable space habitats/workstations ?
>>    The savings on initial cost and on launch weight should be very great.
>>    Add to that the large size and configurational possibilities and you
>>    have an incredibly good deal. Modern materials, esp tri-weave carbon
>>    fiber, could strengthen an envelope and protect against ripping or
>>    [...]

> Well, I think NASA has been doing some nice research on how several materials
> cope with LEO atomic oxygen and radiation. If it turns out those THIN walls
> can't do it, it would have been too soon to talk about inflatable structures
> ...
> Despite that possibility (I hope those materials can do it) the idea seems fascinating from the ecenomic point of view!

    I have heard a number of people claim that atomic oxygen would
    be a problem for inflatable space stations. While this is a
    very reactive substance, I cannot imagine that a suitible
    protective coating is unavailible. Even a few microns of
    vapor-deposited gold should supply considerable resistance
    to atomic oxygen. Vapor-deposition also allows stuff like
    silicon dioxide, aluminum oxide or other ceramics to be
    'painted' on. I have never seen any reports about how well
    stable plastics like teflon cope with O-1 ... though you
    would have to overcoat it with aluminum or gold to keep
    the UV away.

    If O-1 is such a stickie-wickie though, the obvious solution
    is to opt for a higher orbit. Proper disposition of equipment
    and water/fuel chambers around the exterior perimiter would
    give considerable radiation protection - probably better than
    for 'Freedom'. At a higher orbit, these large-volume
    structures would be ideal 'warehouses' for spare materials
    and could be used as a refuge in case some prob made it
    impossible to leave orbit in a shuttle - stuck doors, main
    engine failure, heavy tile damage etc..

    Anyway, this idea, or slightly armored versions of it, seem
    so incredibly economical and simple that only evil politics
    could be behind their suppression - not engineering probs.
    One poster claimed to me that Livermore Labs had claimed
    inflatables could supply all the functionality of 'Freedom'
    for 1/10 the cost ... and they were told to butt out. With
    money tight - it is obvious that there is a lot more interest
    by contractors in stealing every availible penny of govt
    money they can than there is a dream of a new frontier.
    Ten 'Freedom' equivalent stations instead of just one
    ultra-expensive, vibration-plagued, ultra-custom station
    would do a lot to further the utility of space.

    Write your congresspersons and senators ... tell them you
    have heard of this better way ... tell them you are
    disinclined to vote for people that spend ten times what
    is required for projects. The incumbents are more afraid
    for their jobs this year than in a very long time. Voter
    leverage is magnified. Take advantage.

-- Jim Mason

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

Date: Sat, 22 Aug 1992 01:52:29 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Opinions on NLS
Newsgroups: sci.space

I've been noticing a distinct lack of discussion on the New (or is it National?)
Launch System in this group, which kind of surprises me given the number of
other topics that are discussed.
    AIAA's journal has published two major articles on NLS recently, both
very upbeat.  They discussed the lower costs, high reliability, and the Keep It
Simple Stupid aprroach (though I don't think they called it that).  From the
figures I've seen, it looks like the smallest of the launch vehicles would be a
nice commercial rocket and the largest has potential for SEI.  What AIAA has
said about the STME (Space Transportation Main Engine) is also similarly
flattering.  Well, as you may know, I tend to get suspicious whenever someone
is particularly gung ho or especially down on a project, and I'm always
skeptical about vaporware, but I'd like some facts to base my decisions on.
Would anyone like to volunteer an opinion?  (yeah, I know - dumb question :)

--
    Josh Hopkins       [e-mail], or [e-mail]

        "A goal is a dream taken seriously."    -Uncle Walt.

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

Date: Sat, 22 Aug 1992 01:17:04 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Private space ventures
Newsgroups: sci.space

[e-mail] writes:

[on the subject of getting Perot to invest in space - I've changed the order
 of a few statements for clarity]

>If I can convince Mr Perot that it is in his best interest to solve the drought
>problem in africa, then he will do so, If I can convince him that it is in
>his best interest to start a space program, then he will do so.

Believe it or not, personal gain isn't the only things some people base their
decisions on.  Whatever other problems Perot may have, he did strike me as

someone who did things because he thought they were "right," at least once in a
while.  However, space doesn't tend to lend itself to this kind of motivation,
because it takes such a large amount of money and because there just aren't that
many things you can do that give people a warm fuzzy feeling.

>Why pick on Perot.  Why not Bill Gates.  Well, the fact is that Gates (for
>example) doesn't spend his money on non computer related investments. Period.

    Actually, according to the internal IBM equivalent of netnews, Gates has
started investing in movies in the last few months.

>In fact, there are others that might even be better candidates, like the
>prince of that little island who has 29B and is the worlds richest man.

    He's a sultan, the place is Brunei and it doesn't actually cover the
whole island, but you still get extra credit.

>Why don't we pick on him?

    I think we're missing the point.  What space needs more than a rich
investor is a temporarily poor one.  When we have the space equivalent of a
Bill Gates or Ross Perot, who starts of small but makes a big fortune fairly
quickly in a new field, then we'll have the space revolution we're looking for.
Other people would jump on the bandwagon, competition develops and boom - you
get your 486DX 33 booster for less than the price of a present day Apple II
launch vehicle.
    Unfortunately, analogies only go so far.  If space is an analogous
field, we don't have a young Bill Gates that I can see.

--
    Josh Hopkins       [e-mail], or [e-mail]

        "A goal is a dream taken seriously."    -Uncle Walt.

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

Date: 22 Aug 92 04:04:25 GMT
From: William Lewis <[e-mail]>
Subject: Tethers
Newsgroups: sci.space

(In response to a post asserting that non-equatorial beanstalks
 would have to be held up by thrusters or other forms of "cheating")

In article <[e-mail]> [e-mail] (Dani Eder) writes:
>I do not believe this is correct.  It is true that the center of
>gravity of the 'beanstalk' needs to be in Clarke Orbit so it does
>not wobble.  The attachment point on the ground, however, can be
>off the equator.  You elevator in this case will form a catenary,
>i.e. it will be curved.  This will require more structure than the
>simpler vertical case, so it is not usually considered, but it is
>not ruled out on physical grounds.

  Well, it is true that a beanstalk with "nearly zero" force at the
attachment point has to be anchored at the equator. I'm not familiar
with modern anchoring methods, but I suspect that, given the magnitudes
of forces involved in a tether, we can't handle anything except
"nearly zero". (It's possible to arrange for a tether to have zero
force at its attachment, but IMHO real tethers will probably want to
be under tension, to provide a margin of safety and payload. This
tension can be made as small as you want however.)
  I've worked out the equations for a more or less ideal equatorial
beanstalk (brief summary of results: Kevlar isn't quite strong enough to
be practical, but the equation is exponential and a factor-of-ten
improvement of strength-to-weight ratio ("scale height") looks
like it WOULD be pretty practical.) on paper, but I made heavy use
of symmetry arguments so they're not applicable to "off center"
beanstalks. One Of These Days I'll get around to putting a general version
of the equations into Mathematica... but I suspect that it would
be possible to anchor a tether in Nevada, as long as you don't mind
having it lean over. The question, I guess, is whether you can make it
lean shallowly enough to stay in Nevada's airspace.


--
email: [e-mail]             |  Home:  Seattle, Washington   |
     (William Lewis)                     |  47 41' 15" N   122 42' 58" W |
NeXTmail: [e-mail] `-------------------------------'
        --*-- Member, Coalition to Preserve Semantic Vacuity --*--

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

Date: 22 Aug 92 01:21:00 GMT
From: [e-mail]
Subject: Viable alternatives to space? Was ( Re: Private Space Ventures)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Simon Demler) writes...
>> [It bugs me that there are people like H Ross Perot, who
>> themselves have enough cash to finance their own space
>> programs, but that none, so  far, has underwritten one.]
>
>Does it also bother you that these people could be spending some money
>on the drought problems in Africa rather than on some space program...You
>must be one of those space for the sake of space of types...
>
>Come on get real...there are MUCH larger problems that need solving
>on this planet before trying to get peoples private wealth for space
>purposes..
>
Yes that is the argument that was used in 1972 to end the Apollo and look how
much progress has been made with the seven trillion dollars that has been
spent by the American government to end poverty here in the old income
redistribution system.  Yes we can proudly point to the government owned
welfare ghetto's where 90% of all murders in America take place and where over
70% of all drug trafficking comes from.  Yes this argument is the primary
reason the American Government is 4 trillion dollars in debt.

Yes the problems are large and yes they do need to be solved, but you only
have to read this group for a few days to see that there are many on here
trying to do just that, solve the problems of the planet by expanding the
domain of man.  This process is as old as Phonecian and Greek colonization and
trade.  Where else is the wealth available to input into the earth's system
to raise the standard of living and help those poor Africans that you are so
concerned about coming from? What ya gonna do, send Norman Schwartzkopf over
there to end
the anarchy? Go into debt another few billion to feed the hungry over there
today that will just need another infusion next year? What is your alternative?
How would you spend the fifteen billion dollars that NASA gets a year to help
the people?

What do you propose? Let us know and in the flame cauldron of sci.space maybe
we can learn enough toall be saved from a useless life of supporting the
progress of mankind.

Dennis Wingo, University of Alabama in Huntsville

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

Date: 22 Aug 92 01:28:44 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: What happened to Viking?
Newsgroups: sci.space

[e-mail] (Eugene N. Miya) writes:

>In article <[e-mail]>
>[e-mail] (John Burris) writes:
>>What happened the Viking spacecraft?

>Both lands and orbiters were shut down for lack of funds and the need to use
>the antenna resources for other projects (Galileo, Magellan, power
>distribution experiments, SETI, etc.)

    Wait a minute.  Neither Gallileo nor Magellan were major customers of
the Deep Space Network ten years ago.  According to "Quest For Space," lander
1 stopped transmitting on 19 Nov, 1982, orbiter 1 on 7 Aug, 1980.  Lander 2
stopped in April of 1980 and orbiter 2 on 7 July 1981.  I'm quite certain all
of these were spacecraft failures, not shutdowns and the fact that the dates
are spread over more than 2 years supports that.  The landers weren't
transmitting anything but meteorological data by the time they died, so they
wouldn't have been using much antenna time or money.


--
    Josh Hopkins       [e-mail], or [e-mail]

        "A goal is a dream taken seriously."    -Uncle Walt.

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

Date: 22 Aug 92 06:46:29 GMT
From: George William Herbert <[e-mail]>
Subject: With telepresence, who needs people in Earth orbit?
Newsgroups: sci.space

[e-mail] (Gerald Cecil) writes:
>[e-mail] (George William Herbert) writes:

>>Have you talked to someone who builds or works with space robotics?
>No, I was hoping that there might be someone out there who would counteract
>hype from virtual-reality types.

Ok.

>>When anyone suggests replacing humans in the short term, they laugh.
>>Space robotics aren't as strong, for the most part, have less degrees
>>of freedom _and_ less limbs, less end effector dexterity, and more
>>likely failure points than a man in space.  They're safer, but often
>>can't do the job.  (note that an astronaut in EVA can't do everything
>>either.  both together are much more capable.)
>OK, fine.  But the only current `job' for SSF is apparently biological
>research on the long-term effects on microgravity, which means loading
>rats into a centrifuge.  I submit that that can be done with a conveyor
>belt.  Sure, you need people to (dextrously) put the station together
>(or at least to install the rats in their cages), but after that its all
>BF Skinner (push the bar, get the food pellet, wait for the scalpel).

Microgravity biology most certainly is not the only thing that's
going to be done on Freedom 8-)  There's going to be space
and earth science (both with maintenance needs), materials science,
(with maintenance and operational needs) and biology with maintenance
and operational tending needs.

Let's look at Bio first.  Fine control teleoperation isn't very advanced;
I'm not aware of anyone who's done even simple surgery or inserting an
IV line or needs via telepresense.  I'm not saying it's impossible, but
we need a much higher degree of sensors, feedback, mobility, and
reaction time than what we have now.  One hand gloved three-fingered
hand and fuzzy monocular vision aren't all that useful.  Especially
with a potential six second delay in the loop, much smaller than the average
rat's squirm time.  (Why six seconds?  Well, once to TRDSS, once down to
TDRSS ground station, once back to geostationary to a comsat and down
again to NASA's center (Johnson?) who's doing station ops, and then a
second while a NASA computer integrity checks the data.  And then back
again with your response 8-) (I agree that the delay is too long.
Talk to the NASA Freedom telerobotics people about it.  The people
at Rice and UTexas and Johnson who are playing with a prototype
system agree but haven't been able to shorten that delay yet).

And then there are the maintenance problems.

Ok.  Ignoring other detail problems, here's a neat experiment to try and
see how difficult this can be.  Imagine that you've got a bundle of
wires that's worked loose and needs to be tied to a structural member.
Simulate this with two sticks about 2 feet (0.6 meter) long.  Get some
friends to hold these.  Now, you have some string with which you're
going to attach the cable bundle to the structure.  Take one hand
(this is a one armed robot) and put three gloves on it (or one ski glove).
Lie down on your back, have your friends hold the two sticks nearly
at your full arms reach.  Tie the string around the two objects
with one hand and two fingers.  Oh, and you can't cheat and use gravity.
Your friends have to enforce not letting you use gravity.
If you can't do this (hint: about one person in three could last
time I saw the demo) try with five fingers.  Or with two hands with
two fingers each.

A more accurate version allows two arms with two fingers, but blindfolds
the person who's holding (someone else has to teleoperate him).

The scary part is that EVA ops aren't much easier.  But in a pressurized
environment, people have a lot of advantages.

>>Or are you just trying to start a flamewar?
>Well, I'm certainly getting sick of some of the topics that have been
>battered to death here.  We seem to be going round and round on how to
>supply SSF or get the crew away when things fall apart.  I'd still like
>to see a discussion of *why*, in the present scheme of things, people are
>necessary for Earth orbit operations.  Seems to me you could (in the spirit
>of many discussions in this group) free up a lot of $ (possibly some small
>fraction of which could be used to improve the dexterity of robots.)  This
>is, after all, sci.space, not sci.humansinspace.waiting4Soyuz

People are necessary because space is a hard plase to work.  Things
don't work the same there, in ways that we don't totally understand yet.
Robots, especially ones at a distance, are hard to use for aforementione
reasons.  They also break.

We can't get away (now) with just using robots in space.  We also can't
do as much with just people as you can with both people and robots.
If you think that space operations are going to increase in general,
it might be wise to fund both EVA and robotics more than they're funded
now.  Both have a long ways to go, and which one is best in the end
I cannot predict 8-)


   -george william herbert
   [e-mail]  [e-mail]

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

End of Space Digest Volume 15 : Issue 136
------------------------------