Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_3/V11_315.TXT

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Subject: SPACE Digest V11 #315

SPACE Digest                                     Volume 11 : Issue 315

Today's Topics:
                Shuttle shock
          Re: Radar (was Re: Drake Equation
             Re: Dyson spheres, heat flow
         Re: Pegasus launchers, space-going DUCT TAPE
          Re: TV gaffes during Hubble launch
       OOPS (was IMPORTANT MESSAGE for Shuttle Landing Viewers)
          Re: Quick launches ( was: Intelsat
              Re: Decompression and 2001
        IMPORTANT MESSAGE for Shuttle Landing Viewers
         Re: Apollo 13, STS-1, Vostok 1 anniversaries
              Re: Fermi paradox
           How can the shuttle reach higher orbits?
              Re: Decompression and 2001
----------------------------------------------------------------------

Date: 24 Apr 90 17:41:23 GMT
From: sdd.hp.com!elroy.jpl.nasa.gov!aristotle![e-mail]  (Peter Scott)
Subject: Shuttle shock

Fascinating article in _New Scientist_ (we're about 2 weeks behind here)
about ground shock waves caused by the space shuttle overflying Los Angeles.

When the shuttle made a landing pass over L.A. last summer (you'd have
to be deaf not to notice it) the Caltech seismo lab noticed that they
got signals from the sonic boom, all right, but they also got a similar
signal about 12 seconds *before* the boom.  They traced the earlier signal
to a site about 15km SW of Caltech.  Well, that just happens to be in
downtown L.A., with all the skyscrapers.  They theorized that they
were seeing the ground shock wave triggered by the earlier arrival of the
sonic boom over downtown L.A., since the ground waves travel faster than
the air waves.  Was borne out by readings at USC where they got the
ground waves 3 seconds after the air waves, since they are south of
downtown.  Apparently the skyscrapers resonate so much to the boom that
they send out this significant ground wave.

(Article also mentioned how the natural frequency of the Los Angeles
basin corresponded with the resonant frequency of buildings 20-30 stories
high, should be of great comfort to the folk in the B.of.A. towers...)


This is news.  This is your       |    Peter Scott, NASA/JPL/Caltech
brain on news.  Any questions?    |    ([e-mail])

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

Date: 24 Apr 90 21:58:58 GMT
From: usc!samsung!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Radar (was Re: Drake Equation

In article <[e-mail]> [e-mail] (Dan Tilque) writes:

>   Remember, radar operates under an inverse 4th power function."<

 Yes and no.

In terms of the radar set looking at something else, it is an inverse
4th power function, unless the radar wave hits an edge, at which point
it is an inverse square function (I forget whether there is a factor of
1/sqrt(2) in there or not.)

For being detected elsewhere, the radar can be considered a transmitter
with the power dropping off under an inverse square function, focusing
and phase steering permitting, of course.

Philip Fraering
[e-mail]

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

Date: Tue, 24 Apr 90 17:37:57 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Dyson spheres, heat flow


>From: bfmny0![e-mail]  (Tom Neff)
>Subject: Re: Dyson spheres?

>One Dyson sphere might radiate visible infrared, but build enough
>concentric Dyson spheres and little waste might escape.

In the steady-state condition, the operative factors are not the number of
concentric spheres, but the power output of the star and the diameter of
the (largest) sphere.

Thought question: with active pumping of heat, several tricks are possible.
For instance, suppose a civilization is planning to build a Dyson sphere,
and they know that there is a hostile civilization in a particular direction.
In principle, they could install heat absorbers (refrigerators) over that side
of the sphere, and transport the waste heat over to radiators on the other
side. This at least sounds plausible. Now suppose they want to reduce the angle
over which heat is radiated still further, so that 1/4 or 1/8 of the sphere
radiates waste heat at high temperature, while the rest of the outer surface
of the sphere is refrigerated. The question: what are the limiting factors
to this process? I haven't had quite enough thermodynamics to get a good
intuitive grasp of the situation.

Additional question: in "Ringworld", Larry Niven describes a cooling system
for use in a spaceship near a star - since cooling by radiation is impractical,
the waste heat is pumped to a collection point within the ship, from which it
will be dispensed when the ship is no longer near a star. Could this work, and
if so to what extent? I could make a guess, but that's all it would be.
               John Roberts
               [e-mail]

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

Date: 24 Apr 90 21:07:46 GMT
From: [e-mail]  (Dean F. Kling)
Subject: Re: Pegasus launchers, space-going DUCT TAPE

In article <[e-mail]> [e-mail] ("HENRY S. COBB, 1LT.") writes:

>Subject: Pegasus launchers, space-going "duct tape"
>
>Does the Space Shuttle carry duct tape?  You better believe it.
>The In-Flight Maintenance (IFM) kit contains a whole bunch of
>hardware-hacker stuff, including voltmeters, breakout boxes, patch cords,
black electrical tape, and "grey tape", the official NASA term for
                   ^^^^^^^^^^^
>space-qualified duct tape.
>
>Cheers... --Stu
>Round up the usual disclaimers ...
>(COBBHS @ AFSC-SSD.AF.MIL)


  The U.S. Navy, specifically the submarine force also uses and appreciates
this wonder material.  The mil-spec grade typically comes in olive drab (OD),
probably due to inter-service procurement.  The colloquial name is
"EB green" from Electric Boat (a major submarine manufacturer, now a division
of General Dynamics) and the color scheme.  Also a not-so-subtle canard on
reputed assembly procedures of said manufacturer.
  I think it ranks as one of the major cultural artifacts of Western
Civilization.



                Dean
                [e-mail]

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

Date: 24 Apr 90 19:38:02 GMT
From: uhccux![e-mail]  (Jeff Goldader)
Subject: Re: TV gaffes during Hubble launch

In article <[e-mail]> [e-mail] writes:
>Yea!  the Hubble is finally off the pad!  Did anyone else watch it on CBS
>this morning?  The poor reporter pulled a couple of great gaffes.
> [...] Faced with dead air the reporter
>starting saying things like "NASA is holding the shuttle because of a stuck
>valve....the valve is apparently stuck open...this has been a reoccuring
>trouble spot for shuttle launches, delays caused by trouble with THE valve..."

I thought only CNN had morons anchoring their coverage.  Why, oh why did
they have to get Tom Mentier to replace Chas. Crawford on these launches?
When the valve got stuck, Mentier said something like, "Yes, this stuck
valve is very similar to the problem with the APU."  At least Crawford
knew something about the space program.  Once again, Mentier talked all
over the far more interesting Launch Control chit-chat.

*sigh*

Jeff Goldader                        University of Hawaii
[e-mail]      Institute for Astronomy

"So, Lonestar, now you see that Evil will always win- because Good is stupid."
-The Dark Lord Dark Helmet, _SPACEBALLS_

Disclaimer: They don't know what I say, I don't care what they think, and
we're all happy that way.

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

Date: 24 Apr 90 22:08:33 GMT
From: skipper![e-mail]  (Mary Shafer)
Subject: OOPS (was IMPORTANT MESSAGE for Shuttle Landing Viewers)

I said:

   The Shuttle is going to land at 0640 on Sunday, 28 Apr.

I meant:

   The Shuttle is going to land at 0640 on Sunday, 29 Apr.
                                                   ^^




--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
         NASA Ames Dryden Flight Research Facility, Edwards, CA
                   Of course I don't speak for NASA

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

Date: 24 Apr 90 17:45:47 GMT
From: ncrlnk!ncrwic!encad!ensub![e-mail]  (Mark Johnson)
Subject: Re: Quick launches ( was: Intelsat

In article <[e-mail]> [e-mail] I write:
[stuff about Minuteman operational tests deleted]
>
>I will double-check my old files and see if I can find the reference to
>all this; I will either post a confirmation or retraction in a day or two.

The article was in 'Space Horizons' magazine, a NASA/Airforce cheer-leading
publication (privately published, but that was its orientation), dated
April of 1965. I still have a bedraggled copy of the issue in my archives.
There were photos of Minutemen from operational sites being modified with
range safety destruct packages, and then launched...at least one of them
got out of the silo; it's photographed.

BTW, what happened to this magazine????
--
Mark Johnson      WB9QLR/0      NCR Peripheral Products Division
[e-mail]    3718 N. Rock Rd.
[phone]                  Wichita, KS  67226

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

Date: 23 Apr 90 18:01:32 GMT
From: eru!luth!sunic!mcsun!ukc!icdoc!syma![e-mail]  (Nick Watkins)
Subject: Re: Decompression and 2001

In article <[e-mail]> [e-mail] (Dan Tilque) writes:
>By a not so amazing coincidence, this was also a Clarke story.  It was
>written back in the 50's, I think.  Unfortunately, I can't remember the
>name but the plot goes like this:

"Take a deep breath " is title, have a feeling it's in
"The other side of the Sky" but could easily be wrong.

Nick
.

--
Dr. Nick Watkins, Space & Plasma Physics Group, School of Mathematical
& Physical Sciences, Univ. of Sussex, Brighton, E.Sussex, BN1 9QH, ENGLAND
JANET: [e-mail]   BITNET: [e-mail]

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

Date: 24 Apr 90 15:12:51 GMT
From: skipper![e-mail]  (Mary Shafer)
Subject: IMPORTANT MESSAGE for Shuttle Landing Viewers

Wear warm clothes!

The Shuttle is going to land at 0640 on Sunday, 28 Apr.  It's going
to be cold.  Forget the myth that the desert is always hot, it may
be in the low 40s when the Shuttle touches down.  If it's much warmer,
it's because the wind is blowing.

However, if you're an Official Guest and will be hanging around until
the Astronaut Departure Ceremony, it may be warm by then.  Wear layers.

Especially, wear warm footwear.  Official Guests will be standing around
on the cold, cold ramp and all your body heat will seep out of your feet
into the concrete heat sink.  Running shoes work well.  Hillside Guests
will be sitting up on metal bleachers.  The portions of their anatomy
in contact with the bleachers (feet and seat) may get _real_ cold.

For those of you who will be Official Guests, the Usenet RDV will be
in front of the black F-18 (the HARV) 30 minutes after the landing.
See you there.

--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
         NASA Ames Dryden Flight Research Facility, Edwards, CA
                   Of course I don't speak for NASA

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

Date: 25 Apr 90 00:13:24 GMT
From: usc!zaphod.mps.ohio-state.edu!mips!daver!lynx![e-mail]  (Neal Woodall)
Subject: Re: Apollo 13, STS-1, Vostok 1 anniversaries

Mike McManus writes:

>As a big user of "Home-certified, Heavy-duty, Fix-anything, McGyver-style
>Ductape [tm]", I would certainly want some of the stuff in *MY* space-bound
>tool box!

And, as anyone who has ever actually tinkered around with electronics knows,
black electrical tape has 1001 uses also.

>And heck, $32 bucks a roll sounds like a bargain.

For sure! Hey, it helped save the lives of the Apollo 13 astronauts. At approx.
32 $/role, that is a BIG bargain!




Neal

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

Date: 25 Apr 90 00:22:30 GMT
From: sun-barr!newstop!jethro!norge.Sun.COM![e-mail]  (John McKernan)
Subject: Re: Fermi paradox

In article <[e-mail]> [e-mail] (Steve Rehrauer) writes:
>Again I ask: Why does everyone seem to assume that life inevitably
>leads to a technological society?

It's simply a matter of probability. There are a really large number of
planets in the Galaxy. Other areas of the Galaxy have same elements and
physical laws as ours, so you are going to have life. There's lots of
relatively intelligent life on Earth. There's lots of life forms that
use "tools" of some sort (ants, birds, sea otters, etc.). There's at
least one highly intelligent tool using species other than man - chimpanzees.
Given that there are so many examples of intelligent and tool using species
on the Earth, it is logical to conclude that there are other such on
some of the many planets out there.

John L. McKernan.                                                  [e-mail]
Disclaimer: These are my opinions but, shockingly enough, not necessarily Sun's
-------------------------------------------------------------------------------

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

Date: 25 Apr 90 03:04:11 GMT
From: ogicse!cs.uoregon.edu!comix.cs.uoregon.edu![e-mail]
Subject: How can the shuttle reach higher orbits?


Hi there,

    There has been a lot of talking lately about the
    importance of deploying the HST in the highest possible
    orbit (to minimize the number of collisions with
    molecules escaped from the higher layers of the
    atmosphere).

    I know that the shuttle can only reach Low Earth Orbits,
    but what are the problems involved in putting it into a
    higher orbit? Wouldn't it be possible, for instance, to
    include four (instead of two) boosters? Why hasn't NASA
    tried to reach higher orbits with the shuttle? Would each
    launch be much more expensive than what it is now? Is it
    that they consider it enough for their purposes to reach LEO?

Please, comment and feel free to include any suggestions that you
may have on how to make the shuttle reach higher orbits.

/-----------------------------------------------------------------\
| David Solana ([e-mail])                    |
| Department of Computer Science, University of Oregon, Eugene OR |
\-----------------------------------------------------------------/

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

Date: 23 Apr 90 03:39:26 GMT
From: mcsun!ukc!tcdcs!swift.cs.tcd.ie!ccvax.ucd.ie![e-mail]  (Gordon T Gopher at CCVAX)
Subject: Re: Decompression and 2001

In article <[e-mail]>, [e-mail] writes:
>> I am wondering wheter or not a human body exposed to void would explode...
>
> I have often wondered about this as well, and recall reading a sci-fi story
> or two where humans moved between two craft in open space without suits
> (supposedly the decompression problems were solved by hyperventilating, then
> expelling all air from the lungs and leaving your breathing passages open
> 8-O ?).  Also, in light of recent comments concerning the degree of accuracy
> of the portrayal of space flight, etc. in the film _2001_, I couldn't help
> but wonder about the scene where Dave is forced to blow the pod door and
> reenter Discovery through the emergency hatch.  It would appear that he is
> in the vacuum of space for a fair number of seconds, and what's more he
> takes a deep breath and holds it to the point where the veins are bulging
> from his forehead just before the explosive bolts blow.  What gives?

Well I suppose the first sure thing to kiss off would be your ears...
but aside from that, you have to remember that even in a 'perfect' vacuum
the 'suction' is only one atmosphere of pressure - so it's prob. only a lot
worse than a hi flying plane decompressing...

I wonder though, if you'd be better or worse off to hold your breath ?

--------------------------------------------------------------------------------
Neil Conway [e-mail] | Disclaimer ? HA! I'll die of surprise if
            [e-mail] | this even makes it onto the net... :-)
--------------------------------------------------------------------------------

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

End of SPACE Digest V11 #315
*******************