Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V09_5/V9_513.TXT

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Subject: SPACE Digest V9 #513

SPACE Digest                                      Volume 9 : Issue 513

Today's Topics:
                Voyager update
              Re: SETI (was Re: Comets)
           Public domain satellite imagery?
             Fuel for lunar trip
               Phobos 2 images
         Re: Computers for the space station
              Re: Let's go back
             Children born July 20, 1969
----------------------------------------------------------------------

Date: Thu, 22 Jun 89 10:46:54 PST
From: Peter Scott <[e-mail]>
Subject: Voyager update
X-Vms-Mail-To: EXOS%"[e-mail]"

Extracted without permission from  the _Voyager Bulletin_, Mission Status
Report No. 87, June 15:

Three months before Voyager 2's closest approach to Neptune, the spacecraft
is returning images of the planet that show an unexpectedly dynamic atmosphere
on the eighth planet from the Sun.  A recently released set of five images,
taken on May 24 when the spacecraft was 134 million kilometers (83 million
miles) from the planet, shows the large dark spot, smaller white spot,
atmospheric banding, and brightening at the south pole seen in earlier images.
The images were taken through five different filters on Voyager 2's
narrow-angle camera.  The planet's appearance differs markedly as it is
photographed in different colors, probably because of differences in colors
of specific cloud features and the effects of hazes.  Bright features are
more visible in green and orange light, while darker features show more
contrast in violet and blue light.  The degree of dynamic activity was
unexpected in Neptune's atmosphere because Neptune receives only one-tenth
of one percent as much solar energy as does Earth.

NASA SELECT TV TO FEATURE VOYAGER 2 NEPTUNE IMAGES

Beginning Tuesday, June 13, at noon EDT, a selection from the previous week's
images of Neptune from the Voyager 2 spacecraft will be broadcast on the
NASA Select TV system, which uses Satcom F2R, transponder 13, every Tuesday
through August 8.  NASA Select TV is available only in the contiguous United
States since the Satcom satellite is in geosynchronous orbit over North
America.

The broadcast of the images is expected to last about 1 hour and will show
a replay of the first-order reconstruction of Voyager 2's imaging system
views of Neptune.  At the time of the first image in the first broadcast,
Voyager 2 was nearly 2-2/3 billion miles from Earth and approximately 71
million miles from Neptune.

On June 5, the Voyager 2 spacecraft went into the Observatory phase mode.
In this mode the spacecraft begins a series of imaging observations of Neptune
from afar.  Five images are taken every 3 hours, 34.4 minutes (one-fifth
of Neptune's estimated rotation period).  Voyager planetary scientists will
use these images to help study the Neptune atmosphere, already seen to be
more turbulent than that of Uranus and possessing what appear to be variable
"white" spots, covering portions of whole hemispheres.  The spots come and
go with relative rapidity.  Dr. Brad Smith, University of Arizona, said,
"Neptune is now more interesting than Uranus was even at close encounter."
Dr. Smith is the Voyager Imaging Team leader.

The timetable for NASA Select replay of Voyager 2 images, along with the
distance remaining to Neptune and the distance from Earth at the start of
each broadcast, is given below:

Broadcast     Distance to Neptune    Distance from Earth
  Date             (million miles)      (billion miles)
June 13            70.70            2.65
June 20            64.40            2.65
June 27            59.00            2.66
July 4 *        53.73            2.66
July 11            48.30            2.66
July 18            42.88            2.67
July 25            37.45            2.68
August 1        32.03            2.69
August 8        26.60            2.70

* - This date may move later in the week due to holiday observance.

The images to be replayed on NASA Select will include both the actual image
of Neptune as seen by Voyager and engineering and science information about
the conditions of the imaging system and lighting.  This data will appear
alongside each image of retransmissions but will be removed in later, more
processed views.

[...]

Because the JPL facilities associated with the Voyager project are
not completely geared up for the close encounter activity, these views will
be released in video format via satellite only.  There will be no capability
to release individual still photos for the complete video series.  Current
expectations, though, include the capability to release, on a periodic basis,
a set of hard copy views which have received the benefit of further computer
enhancement.  JPL's complete computer processing capabilities will be up
and running, though, for the encounter period from August 21 through 29.
The Post-encounter phase runs from August 29 through October 2, at which
time Voyager 2 will return to interplanetary cruise mode.


Peter Scott ([e-mail])

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

Date: 23 Jun 89 00:46:52 GMT
From: haven!aplcen!stdc.jhuapl.edu![e-mail]  (Jim Meritt)
Subject: Re: SETI (was Re: Comets)

In article <[e-mail]> [e-mail] (Paul C. Duggan) writes:
}In article <[e-mail]> [e-mail] (Jim Meritt) writes:
}>In article <[e-mail]> [e-mail] (Paul C. Duggan) writes:
}
}>}also, the ods I'e heard from some astrophysicists are very low as well.
}>}NOVA had numbers from 10000 down to 0 between 4.  Then there's the
}>}"If they were here we'd know it"  which says, since von neumann machines
}>}are just a step away for ourselves, we could expect another civilization to
}>}have developed them already.  But we don't see any, therefore, we are
}>}the only one
}>
}>1. What does this number mean? 1000 within 100 light years?  Would you
}>please attach some units to this.
}
}It was in the universe.

I must admit, I have never heard this figure.  I have heard one (an early,
very unrealistic and improbable theory of planetary formation that does not
stand up to the observed physics) to millions.  None within an order of
magnitude of 1000.  Where did you get it?

}>2. We are WAY in the boonies. I would not expect a visit, and I am pro-life.
}
}what does pro-life have to do with it?  The von neumann model (not his)
}would have us visited, because they grow exponentially.

So do most lifeforms.  I expect to see VERY few elephants in my neighborhood
because it is a LONG walk.  Exponential growth (unlimited) is not possible
for any extended period.

}>}in light of no evidence for any other intelligent life.  I am an ET
}>}agnostic, and I prefer not to spend money on something I know nothing
}>}about (and have reason to doubt)
}>
}>How odd - when others mention an agnostic belief in something else for which
}>there is no evidence you strongly disagree, and say that they should spend
}>their entire life in service of it.
}
}Christ offers ethical teaching, but he also offers the only way to KEEP his
}ethical teaching.  This is of infinite value to humans.  This aslo isn't
}a question of "service" is a question of my tax money (and the cost of
}my astro book)

Wanna make a guess at the sociological impact of the proof of an
extraterrestrial advanced (more than us) civilization?  This is of
infinite value to humans, because it would concretely SHOW that extinction
does not necessarily be immediately inevitable.  And the $$$ would be
worth it.

}>}BTW, this argument, while comeplling, is similar to the one
}>}"Every war we've had a democrat has been in the white house, therfore,
}>}If we don't want war, elect republicans"
}>
}>And you ofer no rebuttal.  Noted.
}
}I did: I'm saying the argument is flawed.

With a flawed counter.  BFHD.  Saying it, and proving or even showing, are
different things.  You have not done the latter.


........................................................................
The above was test data, and not the responsibility of any organization.
[e-mail]  - or - [e-mail]  - or - meritt%aplvm.BITNET

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

Date: 21 Jun 89 17:08:29 GMT
From: blake!ogccse!verdix!qtc![e-mail]  (Jim Hurst)
Subject: Public domain satellite imagery?

I have a friend who's a school librarian.  We got to talking about satellite
imagery and its application to education.  George got excited about taking a
sabbatical to put together a GIS of local (western Oregon) imagery for kids
to fool around with, and he set me to the task of finding out what kinds of
imagery is available through the public domain.  What he really wants is to
get images of the same area over the years, so we can track the progress of
clear cuts, siltation, and other interesting "cultural" features over the
last decade or two.

    We're not trying to make maps, so registration, control points, and
warping isn't so critical.  I can take care of processing raw data for at least
a few images, more or less regardless of format.  I mentioned the National
High Altitude Photography program, but he's much more interested in electronic
media and multiple images over time.

    I'm aware of the National Space Sciences Data Center at Goddard (the
sys admin is visiting in a week, so I can pick her brain then).  Pointers to
other sources are greatly appreciated.  Send email, and I'll summarize.

                    Thanks!
                    Jim Hurst

UUCP:    tektronix!qtc!jimh              Snailmail:  QTC
       amdcad!qtc!jimh                8700 SW Creekside Place
         sequent!qtc!jimh                          Beaverton, OR  97035

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

Date: Thu, 22 Jun 89 13:56:44 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Fuel for lunar trip


>From: amdcad!weitek!sci![e-mail]  (Dave Rickel)
>Subject: Let's go back

>The 20th anniversary is coming up in a month.  To celebrate, the Smithsonian's
>AIR AND SPACE June/July issue was dedicated to Apollo.  Anyway, it started
>me wondering just what you'd need to get there again.

>...Fuel is, of course, a problem. It seems the solution
>would be to ship up fuel as water to an orbiting cracker/
>refigerator (use expendables for this).
That sounds like a good idea for hydrogen-fueled flights out of earth orbit
in general. Water would take up less volume than the corresponding quantity
of hydrogen and oxygen. Once in orbit, the H2 and O2 would be separated using
the abundant solar power present, and refrigerated. Transfer to other
spacecraft could be human-controlled or automatic. If properly handled,
the reduced launch cost resulting from the use of smaller and lighter
containers for launch could significantly reduce the price of hydrogen and
oxygen in earth orbit. Savings could possibly be reduced further by using a
linear earth-based launcher to shoot the water into space in small containers
in the form of ice.
                           John Roberts
                           [e-mail]

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

Date: Thu, 22 Jun 89 13:57:37 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Phobos 2 images


>From: mcvax!ukc!etive![e-mail]  (Bob Gray)

>A space exibition featuring some of the results from Phobos 2
>opened at the Science Museum in London last week.

>First, a number of the images taken of an area near the
>equator in the infra-red clearly show an area covered with a
>series of regular rectangular features about two miles across.

Mars, I presume.

Though it could of course be a natural formation, it is also important to
watch out for artifacts produced by the imaging systems. Remember that the
pictures from the US landers on Mars showed the sky as being made up of
sharply-defined bands of slightly differing colors or shades, and the still
photographs from the moon showed the landscape covered with little "plus signs"
at regular intervals. :-)

>Second, one of the images shown features the shadow of what
>could only be one of the Martian moons. Except that there
>wasn't any moon in the place and time it would have to have
>been to cast the shadow.
Same comment. Also, assuming this was a picture of Mars, remember that Mars
has an atmosphere and dust storms, so the appearance of the surface from
space changes from time to time. Did the Soviet scientists have any
speculations as to what the images could have been? Chernobyl and other
recent events have shown that the people in the news media are generally
highly skilled at *misinterpreting* images from space probes.
                                   John Roberts
                                   [e-mail]

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

Date: 21 Jun 89 13:25:00 GMT
From: sun-barr!texsun!letni!merch!cpe!hal6000!trsvax![e-mail]
Subject: Re: Computers for the space station


It suddenly occurs to me that HAL 9000 must have picked up some infectious
code from COMPUSERVE or something before departing for Jupiter.

I especially like the part about the "involuntary motor response" of the
RMS arm.

Sounds like a good idea for a movie of the week.

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

Date: 22 Jun 89 20:15:38 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: Let's go back

In article <[e-mail]> [e-mail] (Dave Rickel) writes:

>Delta v        which
>
>5.383 km/sec    Earth Orbit (500 km) to escape velocity (i was too lazy to
>        figure a lunar transfer trajectory, this should be reasonably
>        close)
...
>The 5.4 km/sec figure is nasty; it sounds like we need LOx/LH.  Oh well.
>When they come back to earth, they can use aerobraking, and either go into
>LEO or do a direct reentry.

The delta-v to go from LEO to earth escape is about 3.2 km/s, not 5.4
km/s.  The delta-v from LEO to the lunar surface is 6.0 km/s; the
return is 3.1 km/s (using aerobraking).  Ignoring trip time, it's
cheaper in terms of delta-v to go to many near earth asteroids, or
the moons of mars.

    Paul F. Dietz
    [e-mail]

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

Date:       Fri, 23 Jun 89 10:24:22 EST
From: [e-mail]
Subject:    Children born July 20, 1969

> Would this person's name be "Module" by any chance? I remember hearing
> on the TV News at around the time of Apollo 11, that someone in the
> States had named her newly-born daughter "Module". Wonder what she's
> doing now. Might even have little space probes of her own :-)

I don't know of anyone named "Module", but this makes me wonder when Frank
Zappa's daughter "Moon Unit" was born.  I know she was about sixteen when
she recorded "Valley Girl", and that was a few years ago.  Hmmmmm...

John Coughlin, BULL Kingston        [phone]       <[e-mail]>

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

End of SPACE Digest V9 #513
*******************