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Subject: SPACE Digest V11 #2

SPACE Digest                                       Volume 11 : Issue 2

Today's Topics:
         NASA Headline News for 02/02/90 (Forwarded)
               Re:Temperature of Space?
            1/30/90 Science Times article
               Re: SPACE ACTIVIST ALERT
                  Re: (none)
----------------------------------------------------------------------

Date: 2 Feb 90 18:29:51 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 02/02/90 (Forwarded)

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Friday, February 2, 1990                      Audio: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Friday, February 2......

The New York Times today reports the proposed 24 percent increase
in the NASA budget would be the biggest increase for any major
agency.  President Bush put money behind his pledge to insure
American leadership in space, the paper says.  Also, that the
congressional leaders and budget experts believe it may be
trimmed by a billion dollars or so.  And, both the House and
Senate appear predisposed to approve much of the budget.
Administrator Truly is quoted saying, "this is a most important
budget for us.  It's going to set our course, if we're
successful, for many years to come and cover a wide range of
programs."

It looks like LDEF is in great shape and ready for duty.  Chief
Scientist, William Kinard says, "there's no damage...once we've
taken the experiments off, with just a little cleaning, the
facility could be loaded up all set for another trip."  It
appears the loss of only the top level of the experiments is due
to thermal blankets pulling away.  LDEF lost a small amount of
material during reentry.

The word pollution may no longer hold just a negative meaning.
Preliminary research by Goddard Space Flight Center scientist,
Michael King, reports pollutants in clouds supress the loss of
water.  The result of the water staying in the clouds increases
the cloud life span and prolongs the cooling effect on the Earth
-- competing with the warming effect of atmospheric greenhouse
gases.  Observations of clouds along the path of ships burning
fossil fuels may initiate new predictions about long-range
climate trends.

The Soviet space cycle designed to rescue space crewmen in
distress and help in the repair of malfunctioning satellites was
on TV last night and in today's Washington Post.  The 480-pound,
32-motor vehicle that looks like a floating armchair and similar
to the US manned maneuvering unit performed well on its recent
maiden voyage.

Last night, Kennedy Space Center ground crews removed the
Atlantis heat shields and carrier panels from around the number 3
main engine in preparation for removing the high pressure fuel
turbo pump.  Managers decided to replace the high pressure fuel
turbopump after analyzing X-rays of internal welds in Columbia's
main engines.  Also noted in the postflight assessment process
was a surface depression on a backup seal installed at the
forward end of the righthand motor.  As a result, replacement of
seals with units of known inspection history are taking place.
The change can be made with no impact on the STS-36 launch date.

                            ######





-----------------------------------------------------------------
Here's the broadcast schedule for public affairs events next week
on NASA Select TV.  All times are Eastern:


Thursday, February 8.......


          1:00 PM             NASA Update will be transmitted.


Friday, February 10........

          12 noon             Galileo encounter with Venus press
                              conference from the Jet
                              Propulsion Laboratory.





All events and times are subject to change without notice.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch, NASA
Headquarters, Washington, D.C.

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

Date: Fri, 2 Feb 90 11:56:52 EST
From: [e-mail] (Ken Ellis)
Subject: Re:Temperature of Space?

    To reiterate one poster's comment, interplanetary and interstellar
space does not have a temperature as we think of it here on Earth due
to the very low density of particles. A vacuum cannot have a
temperature because there is nothing there, by definition. Space is
filled with particles at very low densities (e.g. solar wind) but it
still does not have a temperature as we commonly use the term. There
is a kinetic temperature associated with each of the particles that is
a measure of its kinetic energy rather than its ability to warm or
cool an object by convection. The relationship is given by

        mv^2=3kT

where m is the particles mass, v its velocity, k Boltzman's constant
and T the kinetic temperature in Kelvins.

    A more appropriate question, perhaps, is how warm will an
object in space become? The solar wind and interplanetary dust are too
sparse to be able to affect the temperature through convection, which
plays a major role within the atmosphere. In space the primary method
of heat transfer is infrared radiation, major sources in Earth orbit
being the sun, the earth, and to a lesser extent, the moon. These
sources can all heat satellites to fairly high temperatures. This can
cause problems if portions of the satellite heat up unevenly or if the
materials have different thermal coefficients of expansion. Parts can
warp or even come apart, causing the instruments on board to fail. In
order to prevent this, satellite designers try to use materials that
have similar or very small coefficients of expansion. Often they make
extensive use of insulation having a reflective mylar outer layer (remember
the 'space blankets' they used to advertise in magazines?).

    In addition to the infrared heating, the electronics and power
supplies put out considerable amounts of heat. Since there is no
atmosphere to draw the heat away from sensitive instruments by
convection as there is here on Earth, it must be conducted through the
structural members and dumped someplace. This is accomplished with a
radiator that converts the heat to infrared radiation and emits into
cold space. One must be careful, however, that the radiator never
points toward the sun or the Earth since an efficient radiator is also
an efficient absorber.

    Infrared telescopes like that on the IRAS satellite require
cooling to reduce both the detector noise and the amount of infrared
radiation emitted by the telescope itself. Many infrared sensors are
surrounded by 'thermos bottles' that are filled with liquid nitrogen,
which has a temperature of 77 Kelvins (-196 C). The most sensitive
instruments are cooled with liquid helium, which has a temperature of
around 4 Kelvins (-269 C). Some of the more exotic designs will
circulate the cooling liquid through structural members rather than
inserting the instrument in a thermos bottle. For very large
structures, such as the Shuttle Infrared Telescope Facility (SIRTF),
this is the only way to cool the entire structure. Note that the
reason that IRAS is no longer capable of making observations is that
the liquid helium boiled away.

    Where does the 2.7 Kelvin background fit in? This is not a
measure of the temperature of space, but rather an indication of the
background 'color' of the universe. As mentioned before, an efficient
radiator is also an efficient absorber, and vice versa. A perfect
absorber, an object that absorbs 100% of the photons that strike its
surface, is called a blackbody. Blackbodies also radiate photons.  The
wavelengths of the photons radiated depend on the temperature of the
blackbody. A cold blackbody will radiate most of its photons at long
wavelengths (microwave frequencies). As the temperature increases, the
number of photons emitted increases and the average wavelength gets
shorter. A blackbody with a temperature of 300 K (room temperature)
radiates most of its energy in the infrared, at a wavelength of 10
microns. A blackbody with a temperature of 1000 K radiates mainly in
the red portion of the visible spectrum. A blackbody with a
temperature of 6000 K (surface temperature of the sun) radiates
strongly in all parts of the visible, peaking in the green.
Paradoxically, blackbodies don't necessarily look black. In fact,
their color depends on their temperature. If you were to plot energy
as a function of wavelength you would see the shape of the curve
change as you changed the temperature. If the shape of the curve of a
real object is the same as that of a blackbody at a certain
temperature T1, we say that that object has a color temperature of T1.
Thus when we say that the universe has a background temperature of 2.7
K, we mean that if we ignore the photons from all the stars, quasars,
black holes, etc, we are still left with photons that appear to be
radiated by an object with a color temperature of 2.7 K. There is very
little energy, however, and it is all at microwave frequencies. Thus
it will have no measurable effect on the temperature of a satellite
orbiting the Earth.

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

Date: 1 Feb 90 17:18:12 GMT
From: att!cbnewsj![e-mail]  (john.a.welsh)
Subject: 1/30/90 Science Times article

The Science Times section had an article about an electromagnetic
rail-gun (I think they called it a coil gun) that could accelerate
an object to orbital velocity.  They showed a drawing of the proposed
device with the projectile having a heat shield nose cone for protection
at the very high speed the thing would be going at in the atmosphere.
The article says that it will use magnetic levitation to eliminate
rail friction and wear that other proposed rail guns would suffer.
My question is: how fast will an object have to be shot at to achieve
low Earth orbit?  A rocket would have to be carried as part of the
satellite to make sure of the proper roundness of the orbit, so that
would also add weight to the projectile.  Putting a <100 lb. science
experiment payload in an orbit 120 miles up would still require almost
15,000 mph at the top of the arc and then start the small rocket to
stabilize the orbit.  So again, what would the "muzzle velocity" be?

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

Date: 2 Feb 90 22:24:13 GMT
From: sun-barr!cs.utexas.edu!samsung!umich!sharkey!itivax!vax3![e-mail]  (Tihamer T. Toth-Fejel)
Subject: Re: SPACE ACTIVIST ALERT


It is with great sadness that I read the current flaming going on
between Jim Bowery and Dale Skran regarding removing Scott Pace from
his new job at OCST.

I think both agree on the goal that CDSC (California Space
Development Council, ie.  Lloyd Case, Tim Kyger, Terry Savage, and a
host of others) came up with and NSS adopted: The establishment of a
space-faring civilization that will establish communities beyond
Earth.

On the other hand, both DO have vast differences in opinion on
strategy and implimentation.  In addition, each has fundamentally
different values, especially with respect to what NSS should be
doing, ie. should we be rocking the boat (like Earth First!) or
working within the system (like all the companies working on cleaning
up toxic waste dumps, or on recycling technologies).  (Maybe we can
use this difference to our advantage.)

Jim:
>> * As Chairman of the National Space Society's Legislative Committee,
>>   opposed endorsement of Baldrige's Commercially Developed Space Facility
>>   when support for that facility was most needed, thus leaving us with
>>   NO SPACE FACILITY until "Freedom" is built, IF EVER

Dale:
>And a good thing he did for reasons already discussed in sci.space.
>CDSF would wipe out spacehab.

Tihamer:
Sandy Adamson would have made the decision on whether or not to
activate the phone tree, but felt that her involvement with space
station would prejudice her decision, so she had Pace make the
decision.  Being policially oriented (which may or may not be as bad as it
sounds), Pace decided that pushing CDSF would make too many enemies.
From a political view, that is probably correct.  Is it correct from
a long term point of view?   I just don't know, and will not
judge people's honest opinions, especially if I've had positive
dealings with them.

There were some other problems too.  At first, Congress was really
excited about CDSF because all Max Faget and his friends seemed to
need was a free launch.  But then later, it looked like CDSF would
need another $700M for the gov to be an "anchor tennant".  Now $700M
isn't too much, but it upset some congresscritters because it was
unexpected.  One problem is that the market is realtively thin at
present launch costs (therefore inherently unstable), and nobody
knows what the supply/demand curve is for microgravity research.  The
CDSF seemed to be too much for some potential customers and too
little for us (not enough power or automated services).  The National
Research Council published a report in 1988 (which I am trying to get
a copy of) "Industrial Applications of the Microgravity Enviornment"
which may shed some light on the issue.

Would CDSF wipe out spacehab?  or the Freedom station?  In a zero sum
game, yes.  But are we making an either-or assumption unnecessarily?
I believe that it is a difficult judgement call that is highly
dependent on how much you trust NASA, free market forces, etc.
Personally, I think if the space activists could have gotten another
$700M out of congress, specifically for CDSF, the space station folks
(who definitely percieved a zero sum game) wouldn't have batted an
eye.

Jim:
>> * [Pace] Is considered by most activists as working against HR2674

Dale:
>A lie. Scott has always supported HR2674, and worked to make it a reality.

Tihamer:
Only lately have I become actively supportive of HR2674, because
until recently, I was relatively ignorant of it.  Jim Bowery, Andy
Cutler, Mark Volker, and Ron Nickles are to be heartily congratulated
for an excellent job in spearheading HR2674 and making it visible.
It is true that Pace has not been involved from the begining, and his
work for or against it is only visible in the NSS testimony (which
was not presented at the hearings, but inserted in the Congressional
Record).  He does think that it is a "great idea, great concept", but
he does have reservations.  For example, he thinks that asking the
National Space Council, a policy making body, to handle the national
security exceptions is not a good idea - the NSC should make the
policy strong enough so that the pencil pushers hardly EVER let an
exception through.  By analogy, the vice president should not be
contacted every time an overloaded truck is allowed on the highway,
though he may help set the policy that gets those highways built
(insert the traditional quail jokes here :-) ).  I suspect that Pace's
nitpicking might be interpreted as oposition, just as NASA's
nitpicking might be interpreted as constructive and supportive
criticism.

It sure is fun to flame, but wouldn't we rather get up there?  Yeah,
I know this sounds like Bova's traditional call for unity (boring,
boring, I know).  I am reminded of Heinlien's quote (paraphrased)
"Never attribute to malice what can be adaquately explained by
stupidity".  I would go further, for none of us is stupid, but
neither are any of us are omniscient - we are taking honest
differences of opinion, based on different basic values, and
attributing all sorts of evil to the person who disagrees with us.
We gotta realize that Pace, Kyger, Wynn and others are pro-spacers
who have come up from the grass roots and have recently infiltrated
:-) the government but it may take a few years before they can do
anything.  We need people like Cutler, Bowery, and Baxter to stir
things up and keep 'em on their toes.

Meanwhile, I'll just wander around, stars in my eyes, saying "peace,
love and understanding" until I fall on my face -
- then I'll beat the #@$%! out of the $%&*@! who tripped me
(wrestling scholarships are good for something :-)  )
arpanet:  [e-mail]
uucp:  ...{pur-ee,well}!itivax!ttf (Tihamer T. Toth-Fejel)
Industrial Technologies Institute, Ann Arbor, Michigan 48106
[phone] or 4345                  home: [phone]

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

Date: 2 Feb 90 16:31:16 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: (none)

In article <[e-mail]> [e-mail] writes:
>Hello,
>    Could you please send me future copies of the the space digest
>document, thank you.

This is an interesting request -- are those future copies archived somewhere?
I'd like to know how the HST launch is going to make out. :-)



[ Seriously, for the 1.23E57th time - mail these things to SPACE-REQUEST,
not SPACE!!  I'm posting this rather than mailing because TOO MANY readers
seem not to remember this! ]

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

End of SPACE Digest V11 #2
*******************