Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v10_4/v10_418.txt

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Subject: SPACE Digest V10 #418

SPACE Digest                                     Volume 10 : Issue 418

Today's Topics:
          NASA Prediction Bulletins:  Space Shuttle
            Re: Nuclear Reactors in Space
            Re: Nuclear Reactors in Space
                 Space Hotel
         Re: Red Shifts through Random Media
             Pioneer 12 Update - 01/12/90
            Re: Nuclear Reactors in Space
         Re: Red Shifts through Random Media
----------------------------------------------------------------------

Date: 12 Jan 90 22:05:56 GMT
From: helios.ee.lbl.gov!ncis.tis.llnl.gov!blackbird![e-mail]  (TS Kelso)
Subject: NASA Prediction Bulletins:  Space Shuttle


The most current orbital elements from the NASA Prediction Bulletins are
carried on the Celestial RCP/M, [phone], and are updated several times
weekly.  Documentation and tracking software are also available on this
system.  As a service to the satellite user community, the most current
elements for the current shuttle mission are provided below.  The Celestial
RCP/M may be accessed 24 hours/day at 300, 1200, or 2400 baud using 8 data
bits, 1 stop bit, no parity.

STS 32
1 20409U 90  2  A 90 11.75347199  .00050215  00000-0  25599-3 0   113
2 20409  28.4992 124.7920 0003074  76.3320  95.8270 15.79898854   354
--
Dr TS Kelso                           Asst Professor of Space Operations
[e-mail]          Air Force Institute of Technology

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

Date: 12 Jan 90 15:37:13 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (Tim Maroney) writes:

>  The only constraint is that I don't believe fissionables
>should be sitting on top of columns of flame in the Earth's
>atmosphere.
...
>>On another note,  how would a "cold" reactor kill thousands? My "worst
>>case" doesn't manage this much.
>
>Inhaled plutonium dust is a remarkably effective carcinogen.

Tim, there are other fissionables than plutonium.  U-235, for example.
What is your objection to the launching of reactors fueled with this
material?

    Paul F. Dietz
    [e-mail]

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

Date: 12 Jan 90 17:35:00 GMT
From: ucrmath!proton!spin![e-mail]  (David Legg)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (John McKernan) writes:


>... Sweden is implementing reactors with active controls
>which sustain the reaction. In the absense of such controls the reaction
>passively stops. The US is studying such reactor designs.
>

This sounds very much like the CANDU reactor designed in Canada. I believe
that it uses heavy water as a coolant and moderator to slow the neutrons down,
increasing the likelyhood of them colliding with the fuel and sustaining the chain
reaction.  Loss of the coolant results in the neutrons escaping the core
and the chain reaction stops on its own.  I am not a nuclear expert, and I am
sure that there are other control systems which regulate the rate of the reaction.
I am fairly sure that this type of reactor is operational in canada, and that canada
sells such reactors to other countries.



Dave Legg            |Internet: [e-mail]
Radiation Research Lab        |UUCP:    ...!ucrmath!proton!legg
Loma Linda University Medical Center
Loma Linda, CA 92354. [phone]

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

Date: 4 Jan 90 15:12:47 GMT
From: vax5![e-mail]
Subject: Space Hotel

Someone posted a brief article about the Japanese space hotel project.
It was in response to a one-sentence mention in someone else's article.
I was going to grab the space hotel information, but forgot.  Would
someone please email me that?  Thanks.
mike oltz:   [e-mail]  [e-mail]

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

Date: 11 Jan 90 11:27:35 GMT
From: mcsun!ukc!icdoc!syma![e-mail]  (Mark S Madsen)
Subject: Re: Red Shifts through Random Media


(The discussion began with someone saying that they had heard of random
media causing transmitted light to be redshifted.)

In article <[e-mail]> [e-mail] (Anthony E.
Siegman) writes:
>In my opinion, the essence of Wolf's work is not that the
>light gets red-shifted, but that when a broad light spectrum passes
>through certain scattering processes a greater fraction of the red end
>of the spectrum (and a lesser fraction of the blue end) gets scattered
>toward the observer, with the result that the light received by the
>observer appears red-shifted compared to the original light spectrum
                  ^^^^^^^^^^^
>before scattering.

This shows the danger of careless terminology. What you are talking
about (and Wolf, too) is REDDENING. The original discussion was
talking about REDSHIFTING. The former is when the intensity peak is
shifted towards the red, the latter is when the *individual* spectral
lines are all shifted towards the red.

Astronomers have known about the reddening caused by the interstellar
medium since last century, and there are well-known and highly
developed methods for correcting for reddening.

I hope this clears it all up :-)

Mark

--
#######################################################################
##  Mark S. Madsen  ####  [e-mail]  ###################
####  Astronomy Centre, University of Sussex, Brighton BN1 9QH, UK.  ##
####################  Life's a bitch.  Then you die.  #################

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

Date: 12 Jan 90 18:33:11 GMT
From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Pioneer 12 Update - 01/12/90


                             Pioneer 12 Status Report
                                January 12, 1990

     A backup receiver test was performed with Pioneer 12. The test
objectives of this test were: 1) to determine whether the spacecraft
receiver #2 could be acquired with an uplink from a 34 meter attenna
through the AFT omni antenna and 2) to determine if spacecraft
reconfiguration commands could be executed with the same uplink
configuration. Both test objectives were successfully
met.

 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 12 Jan 90 21:04:23 GMT
From: crdgw1!crdos1![e-mail]  (Wm E Davidsen Jr)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (David Legg) writes:

| This sounds very much like the CANDU reactor designed in Canada. I believe
| that it uses heavy water as a coolant and moderator to slow the neutrons down,
| increasing the likelyhood of them colliding with the fuel and sustaining the chain
| reaction.  Loss of the coolant results in the neutrons escaping the core
| and the chain reaction stops on its own.

  I think that about sums it up. Note that not only loss of coolant but
overtemperature will stop the reaction, since the vapor (or in Canada
vapour) is not as effective a moderator as the liquid. I have always
felt that this design was the best possible from a safty standpoint, but
I make no claims to be an expert or to have studdied all current reactor
designs.

  There is an interesting book somewhat related to reactor design called
_We Almost Lost Detroit_.
--
bill davidsen    ([e-mail] -or- uunet!crdgw1!crdos1!davidsen)
            "Stupidity, like virtue, is its own reward" -me

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

Date: 12 Jan 90 23:52:12 GMT
From: sdcc6!sdcc13![e-mail]  (Matt Kennel)
Subject: Re: Red Shifts through Random Media

In article <[e-mail]> [e-mail] (Anthony E. Siegman) writes:
>
>I don't think you'll find the discussion awfully understandable,
>however.  In my opinion, the essence of Wolf's work is not that the
>light gets red-shifted, but that when a broad light spectrum passes
>through certain scattering processes a greater fraction of the red end
>of the spectrum (and a lesser fraction of the blue end) gets scattered
>toward the observer, with the result that the light received by the
>observer appears red-shifted compared to the original light spectrum
>before scattering.

By this description, it doesn't sound any more esoteric than plain
old Rayleigh (dipole) scattering, which I'm sure astronomers have
known about for ages.

So, pardon be for being blunt, where's the beef?

Matt Kennel
[e-mail]

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

End of SPACE Digest V10 #418
*******************