Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_6/V12_703.TXT

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Subject: SPACE Digest V12 #703

SPACE Digest                                     Volume 12 : Issue 703

Today's Topics:
               Galileo article
Re: Who killed Nuclear Rockets? (was Re: The Next Ten Years In Space)
    Re: Air pressure questions   (A human being in vacume)
               Re: Interstellar travel
 Re: NASA's Manned/Unmanned Track Record (Re: Another Russian first)
              Magellan Update - 12/14/90
              Re: Another Russian first
              pressure-altitude relation
             Galileo Update #3 - 12/14/90
              COBE spinning not tumbling
               Re: Light years and such
          Re: Recent DoD Space System Cost Data ...

Administrivia:

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

Date: 14 Dec 90 22:01:51 GMT
From: van-bc!ubc-cs!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo article

Washington Times -- 12/14/90
"Galileo Pictures Far Side of Moon"

"Pictures by the Galileo spacecraft as it boomeranged past
Earth on its way to Jupiter show icy Antarctica and a giant
meteorite impact crater on the far side of the moon."

The story reports that the last photos of the far side of the moon
were made by the Apollo astronauts two decades ago and
quotes Galileo project scientist Torrence Johnson as saying
"this is the first time we've had a chance to use a spacecraft
designed to explore another planet to come back and look at our
own Earth and moon as if we were alien observers."

The Times continues quoting Johnson, "In the process, we're
learning some new scientific things about our own world and
its companion, but perhaps more importantly, it's providing us
a different perspective on our home planet as a fragile world."

The story says that this past Saturday, Galileo swooped 597
miles above the southwest Atlantic Ocean, using Earth's
gravity as a slingshot to help expand the spacecraft's orbit
around the sun so it can reach Jupiter in 1995.  The paper says
that Galileo used Venus for the same purpose this previous
February and will fly by Earth again in December 1992.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 15 Dec 90 19:02:13 GMT
From: usc!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Who killed Nuclear Rockets? (was Re: The Next Ten Years In Space)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>Dumbo.  See Kingsbury's "Notes on Nuclear Rockets".  Basically, Dumbo
>was a somewhat more radical concept than NERVA, and lost out to it when
>funding got tight.

Where can I find this? Is it an article? A book?

Phil F.
[e-mail]

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

Date: 14 Dec 90 18:44:50 GMT
From: hpda!hpcupt1!hpindwa![e-mail]  (David Kinkley)
Subject: Re: Air pressure questions   (A human being in vacume)

On a related note.  Can anybody give me the relationship between
altitude and air pressure.  I'm starting to do a lot of alpine climbing
and have been trying to figure this out for a while.  An equation would
be best but I'll settle for some kind of altitude vs. pressure table
if the numbers are accurate (not that I don't treat everything I read in
this group as gospel ;-)

Dave Kinkley
[e-mail]

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

Date: 15 Dec 90 14:52:30 GMT
From: csus.edu!wuarchive!zaphod.mps.ohio-state.edu!samsung!news.cs.indiana.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu![e-mail]  (/dev/null)
Subject: Re: Interstellar travel

In article <[e-mail]>, [e-mail] (Tony Hamilton, WF1-81, x48142) writes:
> Could anyone tell me what the latest designs are for interstellar starships?
> I had done some real 'light' reading on the subject, and could glean that the
> two most feasible designs were the Air Force's Orion starship (was that given
                         ^^^^^^^^^^^^^^

I believe the Orion was discarded due to technical difficulties - it relied
upon the continuous detonation of atomic bombs in a reaction chamber to supply
the thrust - not much even on the forefront in the way of materials that can
withstand a direct nuclear explosion with no appreciable damage.


> up?), and the Bussard(sp?) Ramjet. Most of what I've heard of these two

The Bussard Ramjet I feel may be the most 'practical' if one can find a way of
a) getting it to 'Ramjet Speed.' and if there is enough hydrogen per cubic meter
that makes the fusion thrust possible.


For the moment, quick efficient interplanetary travel will probably offer
good solutions.

Lightsail, Ion-drive (1970's developed by NASA), etc.


Also, I think the main problem with long term acceleration and fuel
are the biggest technical challenges that Orion and Bussard tried to
circumvent!

Brent Irvine



--

Brent L. Irvine
Malt Beverage Analyst
+-----------------------------------------------------------------------+

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

Date: 12 Dec 90 04:56:15 GMT
From: igloo!ddsw1!corpane!disk![e-mail]  (joefish)
Subject: Re: NASA's Manned/Unmanned Track Record (Re: Another Russian first)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>Skylab 1 got delivered to the Australians in pieces.  Skylab 2 is in the
>NASM.  (Yes, there was a second one.)

And according to AW, Dec. 10, Salyut 7 space station will
reenter and burn sometime around Jan or Feb, 1991.

The orbit is inclined at 51.6 degrees, so most everyone is at
risk-:-)

Salyut was launched in early 1982.

Joe Fischer             [e-mail]

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

Date: 14 Dec 90 17:58:04 GMT
From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Magellan Update - 12/14/90


                        MAGELLAN STATUS REPORT
                          December 14, 1990

     The Magellan spacecraft is in good health and performing nominally.  All
seven STARCALS (star calibrations) since yesterday were successful with small
attitude updates.

     Later today the M0349 mapping sequence will be sent up, the first of six
occulted mapping sequences.  This sequence will shorten the mapping pass by
6.5 minutes in order to accommodate 46 minutes of earth occultation during
the playback.

     Spacecraft engineers met yesterday to discuss the probable causes of the
tape recorder A deterioration.  There is no concern at this time about the
continued use of tape recorder B.  The single tape recorder strategy remains
scheduled to start on December 22.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 14 Dec 90 14:48:23 GMT
From: mcsun!hp4nl!dutrun!dutlru1!dutlru2![e-mail]  (Edwin Wisse)
Subject: Re: Another Russian first

>>In article <[e-mail]> [e-mail] (Frank G.
>>Dahncke) writes:
>>> Now the USSR even has had the first paying passenger in a spacecraft.
>>> Actually, I would have expected this feat to be performed by the US.
>
In [e-mail] (Dan Corbett) writes:
>Does SpaceLab count here? I believe SpaceLab 1 was sponsored by the ESA and
>had a German scientist along.

No it doesn't count. Spacelab was not sponsored by ESA, it was developed and
built by ESA. It was a cooperation with NASA, the deal was that ESA made
Spacelab and got a launch with for it, after the flight Spacelab was NASA's.
Pretty good deal for NASA...

--
___
__  |   |  Edwin Wisse    TU Delft              [e-mail]
___ | | |                 F. of Aeospace En.    [e-mail]

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

Date: 16 Dec 90 06:10:40 GMT
From: bloom-picayune.mit.edu![e-mail]  (Matthew T Velazquez)
Subject: pressure-altitude relation


In article 26774 of sci.space Dave Kinkley writes:

^could somebody give me a pressure-altitude relation...


    Depends on the atmospheric model you use. For the troposphere (valid
up to circa 20 km):

    P(sea level)/P(z) = [1-L/T(sea level)]^^gamma/(1-gamma)

    This reads:

    P of sea level over P of altitude z equals (1 minus L over T of sea
level) to the power of (gamma over 1 minus gamma).

    Where L = 6.5 kelvins/km altitude
    and gamma = 1.41 for air.


For the stratosphere ( valid from c. 20 km - 50 km):

    P(z) = P(sea level) exp(-gz/RT)

    In SI units, Pressure is in Pascals and T is in kelvins. Pressure at
sea level is 1.013 x 10^^5 pascals.

    I'm too lazy to look up unit conversions for the rest of the stuff,
so I guess you're out of luck in that regard.

            T Velazquez
            MIT Aero/Astro
            [e-mail]

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

Date: 14 Dec 90 23:39:50 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update #3 - 12/14/90


                     GALILEO MISSION STATUS
                        December 14, 1990

     The Galileo spacecraft is 2.8 million miles from Earth,
receding at about half a million miles per day.  At 89.3 million
miles, it is closer to the Sun than the Earth is, and will
continue approaching the Sun on this orbit until January 11, when
its present solar orbit will carry it back outward, this time
toward the Asteroid Belt.  Present orbital speed is almost 80,300
mph relative to the Sun.

     Spacecraft health and mission performance continue to be
excellent.  A sun-pointing maneuver was successfully completed
yesterday.  Today the Deep Space Network is sending the first
part of the first post-Earth cruise sequence to the spacecraft.
The current sequence, which includes all the Earth-Moon
scientific observations, runs until Monday morning.  The new
sequence will control spacecraft activities until mid-February
1991.

     Scientific observations of the Earth-Moon system will be
winding up tomorrow, and the scientists are busy analyzing and
interpreting the results.  They will give a first look at these
results at a press conference at 10 a.m. (PST) Wednesday, December 19,
1990, at JPL and via the NASA SELECT satellite TV link.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 15 Dec 90 22:10:27 GMT
From: isis!scicom![e-mail]  (Bruce Watson)
Subject: COBE spinning not tumbling


Bruce,

 As one on the COBE project, let me assure you that the radiatively cooled
instruments on COBE are still very much alive and taking data, although the
cryogenically cooled instruments were turned off after helium depletion
in late September.

 What you observed was sunlight reflected off the three symmetrically placed
solar panels; since COBE spins about its symmetry axis at 0.8 RPM, the
reflection from the panels will vary with a period of about 25 s.

The period just before winter solstice is the best
time of year for naked-eye observations of COBE.

        -Phil Keegstra-                     [e-mail]
 (STX - COBE project at NASA Goddard)       AMARNA::XRPBK

Thanks for that info, Phil.  I'm posting it since I got a number of
responses to my original inquiry.


For those of you interested in observing COBE, it is passing over
Denver at roughly 0:25 UT (23:25 MST) going south to north.  It's
period is 102.7 minutes.  It remains sunlit throughout the year
as a result of its sun-synchronous orbit.  During the rest of the
year twilight occurs too late in the evening for us to see it.
Observe now.  I'll lose it in sunlight before the end of the year.

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

Date: 12 Dec 90 04:03:12 GMT
From: usc!zaphod.mps.ohio-state.edu!rpi!uupsi!cci632!ritcsh!ultb!ritvax.isc.rit.edu![e-mail]  (DAVIS, SW)
Subject: Re: Light years and such

In article <Added.IbMkq=[e-mail]>, [e-mail] ("John Schultz") writes...
>Whenever I hear about a new telescope (such as the HST, etc.) I also hear
>that the new telescope will be able to see even farther into the past.  Now,
>I have no trouble with the idea of light speed, light years, etc., but how
>can one telescope see back farther than another?  Is it due to focusing power,
>or somethin ssimilar?
>
>::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
>: John Schultz                      :Disclaimer : I *pay* for this -   :
>: University of Missouri - Columbia :do you think the bureaucracy      :
>: Bitnet   : [e-mail]  :cares what I say???               :
>: Internet : [e-mail] (128.206.1.1)                 :
>::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
>: Don't dream it, be it...  - Frank N. Furter, "RHPS"                  :
>::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::


    As I read it in many articles about Hubble,the reasont that Hubble can see
"farther" is not because of its size nor focusing power. Compared to the size of
many ground space telescopes,Hubble is only a toy. What Hubble does have as an
advantage is that it escapes the atmosphere and its effects on light. Air currents
disrupt the light from the stars and galaxies (i.e. the "twinkle"). Supposedly,HST
would be able to see twice as far as any ground based optical telescope. I am not
sure how the defective mirror aboard Hubble will effect this though...

            Scott

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

Date: 14 Dec 90 04:51:59 GMT
From: swrinde!elroy.jpl.nasa.gov!zardoz.cpd.com!dhw68k!ofa123![e-mail]  (Wales Larrison)
Subject: Re: Recent DoD Space System Cost Data ...

Thanks for the reference Glenn!
   I had my suspicions the Centaur costs had been cranked into the
Titan program cost - although I don't know why they would do so,
since the upper stage costs for the IUS aren't...

>3) IUS was originally procured not for use on Titan IV, but on the
>shuttle(?).
   Hmm... I think you're right, since the IUS is the poor-man's
"Space Tug" which was originally included in the studies done in
the early 1970's.  However, if I remember correctly, the first
IUS launch was on a Titan. (type Titan 34?).

>4) The cost of the Centaur subcontract and the number of Centaurs
>being built is given in the latest Aviation Leak (but you'll have
>to look it up, I don't remember).
   Found it, 3 Dec 90, Page 17.  "The new Centaur when mated with
the AirForce/Martin Marietta Titan 4 is capable of placing 10,000
lb payloads into geosynchronous orbit. ... General Dynamics will
supply 15 of the upgraded Centaur stages under a $1.3 B subcontract
to Marting Marieeta covering development production and launch
support operations."
   Now, to go back and adjust my original calculations.... Dollar
values are in millions, and are the estimated costs to completion of
the program.  I calculated the current unit average to get an
average unit cost in current dollars.  Current year $ is FY 1991$
(Oct 1990)

                      SAR CURRENT ESTIMATE  (modified)
                                                         Current
 System              BASE    BASE       CURRENT  SYSTEM    Unit
                     YEAR    YEAR $      YEAR $     QTY  Average
 ---------------------------------------------------------------
 TITAN IV(incl Centaur)85   12,620.3   17,009.1    75.0   226.8
(Centaur               90    1,300.0    1,365.0    15.0    91.0)

 TITAN IV(w/o Centaur) 85   --------   15,644.1    75.0   208.6

   Note: the revised current average cost per unit of the Titan IV
is about $208.6 Million with 75 vehicles to be produced, and at
about 40,000 lbs into 100 nmi 28.5 deg orbits, this is still about
$5215/lb.  This number is closer to what I've seen from other
sources.  I've assumed the Centaur costs to be FY 1990 $ to be
conservative.  To a typical shuttle orbit Titan-4 capability reduces
to about 39,250 lbs, or to $5315/lb.  To Space Station orbit of
about 250 nmi, its about to about 38,000 lbs, for about $5489/lb.
To GEO, using a Centaur with itse 10,000 lb capability, the Titan-
4/Centaur cost is about $(208.6+91.0)=$299.6M, for about $30,000/lb.

(Note: I'm posting an equivalent set of estimates for the Delta II)

Thanks again, Glenn.
-------------------------------------------------------------------
Wales Larrison                          Space Technology Investor



--
Wales Larrison
Internet: [e-mail]
Compuserve: >internet:[e-mail]
--------------------------------------------------------------------------

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End of SPACE Digest V12 #703
*******************