Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_0/V10_078.TXT

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Date: Wed, 27 Sep 89 01:30:54 -0400 (EDT)
Subject: SPACE Digest V10 #78

SPACE Digest                                      Volume 10 : Issue 78

Today's Topics:
              Image enhancement
             Re: How is Voyager powered?
     Re: Galileo Jovian atmospheric probe -- is it sterilized???
               RE: SPACE Digest V10 #45
          Re: Searching for the 10th planet
            Re: NSS Dial-A-Shuttle Release
             Re: Aerobraking drag
            Re: Edgar Rice Quayle on Mars.
           Re: Analysis of Martian "Face" Announced
            Re: Edgar Rice Quayle on Mars.
       Re: space organization -- What needs to be accomplished
            Re: Edgar Rice Quayle on Mars.
                  subscribe
               Aerobraking drag
----------------------------------------------------------------------

Date: Fri, 15 Sep 89 19:09:03 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Image enhancement


>From: zephyr.ens.tek.com!tekgen!tekigm2![e-mail]  (Timothy D Margeson)
>About computer enhancement of images... With some images, blurred especially,
>computer enhancement can make astoundeing improvements, with all the accuracy
>one wants, so long as you have a statistically sound sample to begin with.
...
>The images that come to mind that were most striking was that of a license
>plate on the back of a VW bug. The original photo was taken as a bank robbery
>suspect fled the scene of a crime, and a person who was standing near by
>holding a camera snapped a photo hurriedly.

>The photo was thought to be hopelessly blurred due to camera motion - I sure
>couldn't tell what was in the original photo - but the detectives contacted
>a specialty firm, had enhancements done and they were able to reconstruct
>the original image to a detail sufficient to read the license plate number!!

Image enhancement does not add any new information to an image. The
"improvement" of the image is based on certain underlying assumptions on
the appearance of the original object. A blurry photograph of a completely
random set of pixels can not be enhanced, and an image of an object of
unknown properties can not be enhanced with any confidence that the result
is correct. Some assumptions can be made for a typical surveillance
photograph, but filling in a blank left by a dead pixel in the camera just
makes use of an "educated guess" that there are no major discontinuities in
the appearance of the object at that point. (The brain does this at the
"blind spot" in the field of vision.)

I saw an example of the "enhanced blurry photo" on TV. In that case, the
image was blurry because the camera had the wrong focus, so every pixel was
spread out into a circular disk of fixed size. A deconvolution program was
run several times with different estimates of the disk size, until a "best"
reconstruction was obtained. Presumably a similar approach could be used for
motion-induced blur (each pixel distributed into a line segment). The job
was greatly simplified because it was known that the original image was a
group of uniform, smooth-edged characters on a uniform background.
                                John Roberts
                                [e-mail]

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

Date: 15 Sep 89 05:44:46 GMT
From: zephyr.ens.tek.com!tektronix!percy!parsely!bucket![e-mail]  (Leonard Erickson)
Subject: Re: How is Voyager powered?

[e-mail] (nick szabo) writes:

<I would like to see how they plan to protect customers from the radiation,
<and how they plan to dispose of depleated RTG's.

Well, since Sr90 decays via beta decay (28.1 yrs) to Y90 (half-life of hrs)
which decays to Zr90 which is stable, it won't need much shielding. Betas
aren't very penetrating. Gamma emmision I'm not sure about.

Disposal might be via refining the spent unit to recover the remaining
Sr90 for use in new units. But now that I've looked at the decay path,
I'd say Sr90 is a good choice due to the short decay path.

BTW, the Zr recovered from a spent unit might be worth the cost of
extraction, thus making the Sr "free".
--
Leonard Erickson        ...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short

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

Date: 15 Sep 89 17:22:02 GMT
From: uccba!uceng![e-mail]  (daniel mocsny)
Subject: Re: Galileo Jovian atmospheric probe -- is it sterilized???

I think I understand the importance of keeping earth bugs off the
first space probes to land on extraterrestrial objects. However, does
anyone imagine that large-scale space exploration/exploitation can
proceed under sterile conditions? Manned or not, if we start moving
the kind of hardware necessary to build industrial infrastructure,
earth bugs by the zillions will be going along for the ride.

Is anyone giving this serious thought?

Dan Mocsny
[e-mail]

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

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From: "Yorik the Blind"  <[e-mail]>
Subject:  RE: SPACE Digest V10 #45

Re "Annex Canada..."
How about "Make Alaska Contiguous....Sell us to Canada?
At least that way, we'd be put in the right place on maps published
in the US.

On a more space-worthy note:  The thread on Exotic Thrusters is fascinating.
Anybody got some stuff on Light Sail Technology?  Or how about orbital
Rail Gun launchers?  (One in L5 would be down-right handy, if I understand
correctly...If we could get the colonist out of the way... :>)
From what I've been able to piece together, a decent orbital rail gun,
with a useful "barrel aperture" (10 m diameter) is easily within
current technology.  (The last piece was that new "room temperature" super-
conductor.  You know, the one that works at reasonable temperatures, like
-73 degrees F)  That could do wonders for speeding up probe deliveries.  Solar
power would be all you need, for electricity.  You launch a probe from
earth, do a gravity assist from the Earth/Moon system, line up the rail gun,
and give the probe one hell of a kick in the ass.  Then you either use
gravity assists, or a high specific impulse engine, like the Mercury Ion
Thruster.  Or, possibly a light sail.  Or a magnetoplasmadymaic engine.
All of the materials to build the mass driver could be sent up in two or three
shuttle loads.  (I think)  Also, if the rail gun is long enough, you get the
benefits of a tether effect.  For orbit stabilization, use the fact that
you have a long conductor passing through a large magnetic field...Add electri
city from the solar cells, and you can use the earths magnetic filed to help
you maintain orbit...(I know, not really needed in L5, but still...nice
idea anyway.)

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

Date: 16 Sep 89 23:23:03 GMT
From: cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Searching for the 10th planet

In article <[e-mail]> [e-mail] writes:
>I have read in the past about speculations for the possibility of the
>exixtence of a 10th planet.
>Would the deep space probes (Pioneer 10+11, Voyager 1+2) give data
>(for example gravitational anomalies, visual contact) for this search?

Visual contact just wouldn't happen; their cameras are good but not that
good, unless they accidentally happened to go right past it.  Precision
tracking is indeed being done to look for gravitational effects.

>What about the Space Telescope?

Pretty useless unless you know exactly where to point it.  It's built for
in-depth studies, not sky searches.

>Or am I "behind the moon" and the non-existence has already been proven?

Latest word is that if it exists, it's almost certainly either quite small
or a long way out.
--
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry [e-mail]

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

Date: 16 Sep 89 01:45:18 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: NSS Dial-A-Shuttle Release

In article <[e-mail]> [e-mail] (Tom Neff) writes:
>> The two extraordinary [Galileo-] Earth encounters, which will occur in
>> 1990 and 1992, will provide the first ever deep space look at our own
>> planet.
>
>I dispute this.  If memory serves, it was Mariner 10 in 1973 which
>turned its cameras backward after orbital insertion to Venus and
>Mercury, and gave us our first long shot view (a rather famous one) of
>Moon and Earth together in space.

You've got a bad chip in that memory, Tom. :-)  Voyager 1 shot the
Earth/Moon photo on Sept 18 1977.  There have been others; I recall a pic
of Earth from Giotto's camera (and a disappointing one it was, too, since
the camera was designed for rather different circumstances).

>However, it may be that the National Space Society wasn't organized at
>that time, so it doesn't count.  :-)  [two points Neff, nice bash job]

Well, actually NSS as such didn't exist in 1973, and I don't think L5 did
(although I'm not sure of the dates for it), although NSI might have.
Of course, whether NSS has *ever* existed in any useful way is somewhat
debatable... :-)    [hey, one good bash job deserves another!]
--
V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry [e-mail]

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

Date: 17 Sep 89 04:41:52 GMT
From: psuvm![e-mail]
Subject: Re: Aerobraking drag

In general, it can safely be assumed that an optimal aerobraking maneuver can
"kill" (square root of 2)*(planet's surface escape velocity) hyperbolic excess
velocity

****************************************************************************
Mike Williams
[e-mail]

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

Date: 15 Sep 89 13:41:03 GMT
From: tank!eecae!netnews.upenn.edu!eniac.seas.upenn.edu![e-mail]  (Daniel P. Barron)
Subject: Re: Edgar Rice Quayle on Mars.

In article <[e-mail]> [e-mail] (James N. Price) writes:
>Quayle may be pro-space right now because (and only because) it's
>politically fashionable.  Next week (month, year) he may be pro-
>(or anti-) rail transportation, abortion, civil rights or whatever
>for the same reason.

And lots of people bust on Quayle because it's politically fashionable right
now.  Do you have any references to back up your allegations that Quayle's
position on these important issues has changed in the past?  If so, let's
hear them.  I'm not supporting or criticizing the guy, I really don't know
much about his political career, but jumping on the Quayle-as-Moron band-
wagon without thinking is no better than what you accuse him of.

Ever the Devil's advocate...

db


________________________________Daniel Barron__________________________________
______________________________________ ________________________________________
"There are four types of homicide:    | E-mail: [e-mail]
 felonious, excusable, justifiable    |         [e-mail]
 and praiseworthy."  --Ambrose Bierce |         [e-mail]
______________________________________|________________________________________

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

Date: 15 Sep 89 17:34:17 GMT
From: [e-mail]  (Dean F. Kling)
Subject: Re: Analysis of Martian "Face" Announced

Summary: Suspicious of "correlations".
References: <[e-mail]> <[e-mail]> <[e-mail]>

In article <[e-mail]>, [e-mail] (Gene Gross) writes:
> In article <[e-mail]> [e-mail] (Jeff Hunter) writes:
> >[e-mail] (Jangling Neck Nipper) writes:
> >> In article <[e-mail]> [e-mail] (Ted Johnson) writes:
> >>
> >
> >    So he started in on nearby objects. There's a hill (to the north?)
> >that is roughly like a five-sided pyramid. The faces are all about the same
> >length, and fairly flat. Hoagland pointed out the resemblance in proportion
> >to Da Vinci's famous sketch of man in a circle. He concluded that the
> >hill was a reinforcement of the face directing a message to mankind.

[ stuff on resemblence auto commercials deleted ]

> >    He then started in on a nearby ridge saying it was "obviously
> >artificial". There's a notch in the ridge, and if you line it up with
> >the eye of the "face" (or the main street of the "city", I forget) you
> >get a completely useless direction.
> >    But wait! If you calculate back in time as Mars' poles precess
> >the notch will eventually line up with some star or other on the
> >vernal equinox, or the summer solstice. Hoagland picks one of these
> >matches and thereby "proves" that the whole complex was created at some
> >ancient date.
> >

    A few months ago PBS in Seattle had a British TV show that discussed
these  kinds of ad-hoc correlations.  As an examle they took Stonehenge,
the Salisbury Cathedral, and several local farms and drew dozens of striking
conclusions based on their geographical realtionships, sight lines, and
long distance relationships to other English monuments, and to solstice lines,
etc.  The obvious conclusion they drew was that the whole complex *must*
have been part of an overall coherent design, by a single culture.
There were just *too* many "coincidences" to be explained by mere chance!
The lesson was that if you look hard enough for post-facto relationships,
you will find them.


            Dean F. Kling
            cs.washington.edu

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

Date: 16 Sep 89 04:07:39 GMT
From: loft386![e-mail]  (Doug Ingraham)
Subject: Re: Edgar Rice Quayle on Mars.

In article <[e-mail]>, [e-mail] (Steve Rehrauer) writes:
> [ All this assumes that he actually said the Mars bit, which I find semi-hard
>   to believe, even considering the source.  Still, as a friend is fond of
>   saying -- "Dan Quayle: The best impeachment/assassination insurance a
>   President could ask for!" :) ]

Yes, he said it.  I saw the brief excerpt on CNN that evening.  There are
no comedians that could have parodied him with the conviction he made
these statements.  Anyway, I am certain he has been corrected on this by
now.  After all he really isn't stupid.


--
Doug Ingraham (SysAdmin)
Lofty Pursuits (Public Access for Rapid City SD USA)
uunet!loft386!dpi

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

Date: 17 Sep 89 03:47:47 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: space organization -- What needs to be accomplished

In article <[e-mail]> [e-mail] (pezely) writes:
>7. Raise vast amounts of money from the general public and private
>investors (Billions-of-dollars range) to help pay for the station.

Doesn't necessarily need to be billions.  If you're willing to launch
on Soviet boosters, it can probably be done for about $500M.  This may
require limiting the sophistication of the on-board hardware to avoid
hassles from the US government, though.  Unless you're willing to wait
until the Australians are launching (Soviet-built) Zenits from Cape York.
--
"Where is D.D. Harriman now,   |     Henry Spencer at U of Toronto Zoology
when we really *need* him?"    | uunet!attcan!utzoo!henry [e-mail]

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

Date: 17 Sep 89 20:47:58 GMT
From: haven!uvaarpa!virginia!kesmai![e-mail]  (Kelton Flinn)
Subject: Re: Edgar Rice Quayle on Mars.

In article <[e-mail]>, [e-mail] (N = R*fgfpneflfifaL) writes:
>     Vice President Dan Quayle, explained why the
>     United States should undertake a manned mission to Mars:  "Mars is
>     essentially in the same orbit.  Mars is somewhat the same distance
>     from the Sun, which is very important.  We have seen pictures where
>     there are canals, we believe, and water.  If there is water, there is
>     oxygen.  If oxygen, that means we can breathe."

  I saw this clip on CNN, and was woefully embarrassed for the Vice
President. Then the CNN reporter came on and said something to the
effect of "The Vice President is displaying his misunderstanding of
science here, everyone knows that Mars has no atmosphere." The
last part of the sentence I remember distinctly. *THAT* made me
mad! Its one thing for the Vice President to make a silly statement
because his staff didn't brief him properly. Thats bad enough. Its far
worse for a member of the media to make a blatantly false statement
that is easily checkable. The reporter was not on camera, required to
answer a question on the spot, they have all the time they need to
get it right. Harumph!
  Kelton Flinn

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

Date:         Fri, 15 Sep 89 12:15:14 CDT
From: "Michael W. Watterud" <[e-mail]>
Subject:      subscribe

sub space

Michael Watterud   UD017158 @ NDSUVM1

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

Date: 15 Sep 89 19:08:30 GMT
From: nis!viper![e-mail]  (David Messer)
Subject: Aerobraking drag

Does anyone have a "rule of thumb" for calculating the drag on a
hypersonic object passing through an atmosphere?  What I really
want to determine is how much a meteor or asteroid would slow
down while passing through the Earths atmosphere.

Any help you can give me will be appreciated.
--
Remember Tiananmen Square.           | David Messer       [e-mail] -or-
                                     | Lynx Data Systems  ...!bungia!viper!dave

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

End of SPACE Digest V10 #78
*******************