Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_3/V13_359.TXT

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Subject: SPACE Digest V13 #359

SPACE Digest                                     Volume 13 : Issue 359

Today's Topics:
               Re: Increasing value/lb.
     Re: Chemical rocket complexities (was Re: "Follies")
              Re: "Face" on Mars
       Re: Why does every SAR have another resolution?
              KSC Shuttle Launch Passes
             Shuttle Frequencies
        Re: solid motor failure at edwards...
           Space Stations, Money, Startrek
              Re: How 'bout them Titans?

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

Date: 4 Apr 91 21:33:07 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Increasing value/lb.

In article <[e-mail]> [e-mail] (Nick Szabo) writes:

>instead of $1,000/kg or more).   This uses "today's technology" in the
>sense that no nanotechnology, AI advances, etc. are needed.  The biggest
>limiting factor: we aren't tracking the #@!$!$#@ comets yet!  We _do_ need
>advances in astronomy to make this scheme work.  I hope to see such
>advances in the next 5-15 years -- a combination of the new telescopes
>coming on-line, and a new emphasis on comets as space resources by the
>space community.  Small asteroids (silicon, metals) could be retrieved
>with a somewhat more sophisticated effort, but this effort would not
>necesarily involve more launch mass.   Ice is much easier to mine than
>hard dirt and rock, but we will need to also develop techniques for the
>latter.  As is usual with technology, the expertise and products gained
>from the smaller-scale operations will allow us to bootstrap into the
>larger-scale tasks of building large-scale space industries and space
>colonies at a far lower cost than that of trying to accomplish such a
>gargantuan project from scratch.

>Now, that is not to say that this is easy.  Intellectually, at least,
>this path is much more difficult than the old chem rocket/space station/
>Moon/Mars paradigm.   However, economically and politically it is far,
>far cheaper.   If we follow the old failed paths, we are doomed to defeat.
>By consiously working towards increasing value/lb. and letting the
>solar system do the work for us, we _can_ achieve space colonization,
>the "work of generations" (Goddard).

If I were you I would not be so hasty designing the apparatus for
moving the comet. It would be much more constructive for you to
simply devote whatever efforts you intend to make towards finding
out about the comets.

Our knowledge of comets is extemely limited. Although I think they
are important, anything more than reconnisance is unjustified.

In short, don't count your eggs before you know whether or not
chickens or pterodactyls will result on hatching day. And it might
turn out that moving a comet is a more intractable problem than
you think. I am trying not to be closed-minded, especially towards
your idea about using solar thermal power to move the comets :-)
:-) :-) :-) :-) :-) :-) , but we need to keep _all_ of our options
open.

To summarize, though, you should be working on finding out more
about these things instead of making a very general model for moving
something.

Phil Fraering
[e-mail]
"The reserve of modern assertions is sometimes pushed to extremes, in
which the fear of being contradicted leads the writer to strip himself
of almost all sense and meaning." - Winston S. Churchill

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

Date: 4 Apr 91 22:39:18 GMT
From: mnemosyne.cs.du.edu!isis![e-mail]  (Glenn A. Serre)
Subject: Re: Chemical rocket complexities (was Re: "Follies")


Excuse me, I may have missed some of the Chemical rocket complexities
discussion (problems with the news server), but what happened to the technical
 reasons for why launch costs can't be significantly lowered?

So far, I've heard.
1) High-power turbopumps and cryo fuel.
2) Large "ductile" structures.
3) Tracking
4) Control, i.e. gyros, etc.
1) and 2) are bogus, see my recent post , Re: Follies, I think.
For 3) and 4), anyone out there have any expertise?

Customers causing (at least partially) high costs.
1)  Does anyone (else) who has worked for a rocket company have any comment?
2) Are there any customers out there?

One last thing:  Why is this whole topic being argued as rockets vs. exotic
technology?
Rocket development should be made more commercial, as opposed to
governmental.  Anyone out there disagree?
Government-sponsored development should concentrate on exotic technologies
like gas-guns, EML, tethers, etc.  Anyone out there disagree?

More ramblings from:
--

--Glenn Serre
[e-mail]
--

--Glenn Serre
[e-mail]

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

Date: 3 Apr 91 11:02:09 GMT
From: dev8.mdcbbs.com![e-mail]
Subject: Re: "Face" on Mars

In article <[e-mail]>, [e-mail] (Keith Hamburger) writes:
> Perhaps, if one is interested, he should check his local library for a copy of
> the book.  If the ideas prove worthwhile he could then purchase other books on
> the subject.  (please note that I am not going to even get it at the library,
> I don't need to be told that I should take anything on faith just because it
> might be possible.)
>
> Keith
Are we never to be rid of this? I worked on the Viking flight control team, and
have seen many orbital photographs of that same piece of real estate. Only in
the one photograph, when the sun is at a particular angle, does the surface
feature take on a vague semblance to a face. And the photo most commonly
displayed to the public has been severely contrast enhanced to bring up this
feature.

  As to certain sensationalist works claining to see remains of a city hidden
in the shadows of that photo, their claims are always "proved" by copies of
copies of copies of the photo in question, usually shot through a poor half
tone screen. No such artifacts are visable in the original source data.

  Mars has never had a civilization. The debate is STILL going on as to whether
the life science results found traces of life, or merely the chemical
precursors to life which stopped evolving when Mars lost its water.

  If you want to look for non-terrestrial life, current thought holds that the
most likely place to find it will be floating high in the atmosphere of
Jupiter.

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

Date: 4 Apr 91 18:54:40 GMT
From: usc!elroy.jpl.nasa.gov!jato![e-mail]  (Van Snyder)
Subject: Re: Why does every SAR have another resolution?

In article <[e-mail]> [e-mail] (Daniel Fischer) writes:
>From NASA NEWS RELEASE 91-34 of February 27, 1991 on the RADARSAT spacecraft:
>> The satellite's synthetic aperture radar (SAR) will be ... scanning the
>> Earth in swaths varying from 50 to 500 km. The SAR will produce high-resolu=
>> tion (10 to 100 meters pixel size) images of the Earth's surface...
>
>Now we all know that the Magellan in its orbit around Venus produces swaths
>some 25km wide, with a resolution of approx. 120 meters. Why can the resolution
>of RADARSAT's SAR be so much better, about a factor of 10? This can't be due
>to a lower orbit alone, I presume. Also, why can RADARSAT have many more
>pixels across the swath's width (according to this article 5000) compared to
>Magellan (200)? Does that depend on their antennas or on the data processing?

The SAR resolution depends on the orbit, transmitter power and antenna aperture.RADARSAT has a more powerful transmitter, a bigger antenna and a lower orbit.

The downlink data rate, and thus a reasonable limit on the number of pixels one
should collect per orbit, depends, in order of importance, on: distance,
transmitter power, antenna aperture and efficiency, data processing.  Distance
is by far the most important.  Since the transmitter power on Magellan is
essentially fixed, as is the antenna aperture, the possible data rate at a
given signal-to-noise ratio varies inversely as the square of the distance.
The data rate today is 268k baud.  From near earth orbit, several mega-baud is
possible with the same transmitter power and antenna aperture.

--
[e-mail]
ames!elroy!jato!vsnyder
[e-mail]

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

Date: Thu, 04 Apr 91  14:45:44 EST
From: Michael Petersen <[e-mail]>
Subject: KSC Shuttle Launch Passes

     Can anyone tell me how I can obtain a KSC visitor pass for a
shuttle launch.

     I've seen a launch before from a location on the space coast,
but I hear the view from the visitor area in KSC is magnificient!

     Thanks!
       --Mike
         [e-mail]

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

Date: 4 Apr 91 16:55:13 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!wuarchive!emory!ducvax.auburn.edu!eng.auburn.edu![e-mail]  (Brian Hartsfield)
Subject: Shuttle Frequencies


Could somebody post or e-mail me a list of frequencies where the shuttle
air-to-ground communications can be picked up?  I am in Auburn, AL.

Brian Hartsfield

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

Date: 4 Apr 91 20:57:46 GMT
From: orca!bambam![e-mail]  (Bob Pendleton)
Subject: Re: solid motor failure at edwards...

In article <[e-mail]>, [e-mail] (arvey j. shier) writes:

> ....it is possible that
> an advanced version of the 7 segment motor is in development...

Hercules Aerospace has a contract to build an advanced version of the
Titan IV solid boosters. I don't know all the details. But it has a
larger diameter and a graphite fiber/epoxy wound case.

--
              Bob Pendleton, speaking only for myself.
   [e-mail] or decwrl!esunix!bpendlet or utah-cs!esunix!bpendlet

                         Tools, not rules.

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

Date: 4 Apr 91 23:27:25 GMT
From: tahoe!jimi!herbert![e-mail]  (Doug Phillipson )
Subject: Space Stations, Money, Startrek


    Hi net world! Please indulge me for a moment on FRED.

First, I love space science, and almost anything that will get us
(Human race) off this rock called Earth.  But I believe the Freedom
station is a waste of taxpayers money.  It can not be manned for
any great period of time by the same people due to the lack of gravity.

    Yes I know that is the whole purpose of the darn thing.  Well
the follow on to FRED must be a cylindrical station that rotates for
LONG duration living, I'm talking years here.  And the micro gravity
experiments can be done at the zero G hub of the station.  Now with
FRED you are going to have to take a lot of exercise equipment up
to orbit just to keep the scientists from becoming silly putty.
And a good measure of their time will be taken up using that
exercise equipment.  Why don't we start our space research from
the start in a station we won't have to scrap in 10 to 15 years.

    I would strongly support even with a tax hike (oh there is that
republican dirty word) a deluxe rotating station.  But to throw billions
of dollars into a station that is doomed from the start to obsolescense
is insanity.  Yes I know your building it to be expandable.  So now we
will have a expanded obsolete station that people still can't remain at
for extended periods.  Lets not throw money at a station just to have a
station.  Lets not make another Skylab.  Lets build one that will take us into
the next century proudly.  Quayle are you listening? NASA are you feeling
the real pulse of the people? Mr President are you serious about space?

                Douglas Phillipson
                Visionary Programmer

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

Date: 4 Apr 91 07:27:01 GMT
From: hao.hao.ucar.edu![e-mail]  (Graham Murphy)
Subject: Re: How 'bout them Titans?

I'd be interested in knowing where the sound track for CNN's
footage of the explosion came from---presumably not the
control room.  Shortly after the Titan was destroyed,
one hears a voice in the background say,
"Is it supposed to do that?"
followed by another voice giving a very emphatic "No!"

Graham Murphy


High Altitude Observatory
National Center for Atmospheric Research
P.O. Box 3000, Boulder CO 80307-3000. Ph:[phone]; Fax:[phone].
INTERNET: [e-mail]; Solar PO: GMurphy@SOLAR

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End of SPACE Digest V13 #359
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