Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_1/V11_146.TXT

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Subject: SPACE Digest V11 #146

SPACE Digest                                     Volume 11 : Issue 146

Today's Topics:
        Re: Resolving Power of Hubble Space Telescope
         Re: Sci. Am. Lunar Telescope Article
               Re: SR-71 at Smithsonian
        Re: Resolving Power of Hubble Space Telescope
        Re: environmental impact of antimatter rockets
         NASA Position in Intelligent Systems
               Repost of "High Flight"
          Re: Subscription to AW&ST in UK ?
               Voyager and other probes
              Re: Challenger last words
               Re: SR-71 at Smithsonian
----------------------------------------------------------------------

Date: 14 Mar 90 04:31:42 GMT
From: cs.utexas.edu!samsung!aplcen!haven!uvaarpa!hudson!astsun8.astro.Virginia.EDU![e-mail]  (Greg S. Hennessy)
Subject: Re: Resolving Power of Hubble Space Telescope

In article <[e-mail]>
[e-mail] (David Ray) writes:
#OK, so the HST optics have resolving power of 0.1 arcseconds.
#               ^^^^^^
#Now, what about the spacecraft?

We will find out in a few months. The documentation I have seemed to
state that there was a design goal of 0.07 arc jitter. I can recheck
my references if it is important enough. Note: this was the spec, we
don't know what it will do (yet).

#It is my understanding that this 0.1 arcsecond requirement
#is the most stringent attitude control requirement of all spacecraft
#history. Is this true?

Yep, and one of the reasons HST was so expensive. It is HARD doing
that accuracy.

#1. Whenever anything moves on the spacecraft, such as filter wheels
#   on the focal plane, electrical relays tripping, etc., this "shakes"
#   the spacecraft, and I assume more than 0.1 arcseconds. How is this
#   handled? Does one wait for the atitude "jitter" to dampen, and then
#   start to take data?

I know some of the filter wheels have counter wheels. I think some
don't.


-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      [e-mail]
 UUCP:        ...!uunet!virginia!gsh7w

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

Date: 13 Mar 90 17:41:54 GMT
From: news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew![e-mail]  (Brian or James)
Subject: Re: Sci. Am. Lunar Telescope Article


 Well, the light diffusion could come from booster pollution
(or lunar factory pollution) and the light source for the
odd shadows *might* be from a nearby antimatter powered
shuttle exploding.
                    JDN
PS: See original article for smilies.

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

Date: 13 Mar 90 21:09:11 GMT
From: skipper![e-mail]  (Mary Shafer (OFV))
Subject: Re: SR-71 at Smithsonian

In article <[e-mail]> [e-mail] (Greg Lindahl) writes:

>As of yesterday it [SR-71] was sitting outdoors at Dulles, and you can see it
>from one of the terminals. Has red paint (?) over the windows so that
>you can't see inside.

The red things are shields.  They're on the windows, the inlet doors,
the inlet, and something on the turtleback, behind the cockpit.

There are also red shields or covers on the air data system, including
angle-of-attack vanes.

--

Mary Shafer  [e-mail] or ames!skipper.dfrf.nasa.gov!shafer
         NASA Ames Dryden Flight Research Facility, Edwards, CA
                   Of course I don't speak for NASA

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

Date: 14 Mar 90 01:14:28 GMT
From: agate!sag4.ssl.berkeley.edu![e-mail]  (David Ray)
Subject: Re: Resolving Power of Hubble Space Telescope

OK, so the HST optics have resolving power of 0.1 arcseconds.
               ^^^^^^
Now, what about the spacecraft? This may be a moot point, but I am
curious about the attitude control (i.e. pointability) of the HST
spacecraft. It is my understanding that this 0.1 arcsecond requirement
is the most stringent attitude control requirement of all spacecraft
history. Is this true?

Just curious, does anyone have any information on the attitude control
plan for the HST spacecraft? I speculate the following scenarios:

1. Whenever anything moves on the spacecraft, such as filter wheels
   on the focal plane, electrical relays tripping, etc., this "shakes"
   the spacecraft, and I assume more than 0.1 arcseconds. How is this
   handled? Does one wait for the atitude "jitter" to dampen, and then
   start to take data?

2. In order to know that the spacecraft attitude is within the 0.1
   arcsecond (or whatever) allocation, a separate, independent system
   such as a star tracker or inertial tracking system must be used.
   What is planned to be used and what is its sensitivity?

I posted this question some time ago and noone responded. Does anyone
have information on this?

Dave Ray                            [e-mail]
Space Sciences Laboratory
UC Berkeley

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

Date: 13 Mar 90 17:29:00 GMT
From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: environmental impact of antimatter rockets

In article <[e-mail]> [e-mail] (Christopher Neufeld) writes:
>   ... I thought that a 280kT blast every second,
>for a couple of minutes, in a rising column would produce a firestorm of
>sufficient size to extend the range of the damage considerably beyond that
>of a single explosion...

If it goes straight up, which would be the sensible thing to do, damage
should remain fairly localized.  One would assume that sane planners would
put the launch site somewhere well away from inhabited areas, minimizing
the number of things that could be ignited.  The ability of nuclear
explosions to cause fires in non-urban areas is vastly exaggerated; the
only detailed study I've seen (which was looking at the nuclear-winter
aspects) concluded that croplands and wildlands simply aren't very
flammable most of the time.  Croplands burn well only when the crops are
dry, just before harvest, and the times are staggered so it's rare for
large areas to be flammable at one time.  Localized forest fires would
be a possibility, but conditions conducive to major spreading of forest
fires are quite rare.  Seasonal variation is considerable, too:  if you
launched from a northern area in winter, the problem would be pretty
much nonexistent.

Finally, just to be picky :-), a firestorm (as opposed to widespread fires)
requires a precise set of conditions and isn't that easy to do even when
you are deliberately trying.  After the Hamburg firestorm was understood,
practically every major WW2 bombing operation tried to raise a firestorm,
and only the Dresden raids succeeded.  (Okay, for those who are puzzled
by this:  a firestorm is not just a big fire or a whole bunch of fires.
It's a very specific phenomenon in which a large area is ignited at about
the same time, the updraft from the fires creates an inward wind, the wind
fans the flames, and, um, positive feedback goes to completion, stopping
only when there is nothing left to burn.  It's immensely destructive but
doesn't get started easily; in particular, even a gentle breeze will
prevent it.)
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 13 Mar 90 18:14:03 GMT
From: ptolemy![e-mail]  (Nancy E. Sliwa)
Subject: NASA Position in Intelligent Systems

****************

Job Announcement - Branch Chief
National Aeronautics and Space Administration
Ames Research Center

The Information Sciences Division is seeking applicants to lead
the Intelligent Systems Technology Branch.  The branch chief serves
as the technical and administrative head of 30 personnel engaged in
research and development of high performance intelligent computational
systems for aerospace missions.  Current branch projects include parallel
processing systems (particularly software infrastructure for symbolic
applications), dependable systems including fault management and
software testing, analog optical information processing, neural
networks, multiprocessing architectures, and network analysis.

Applicants should hold a PhD degree or equivalent experience,
have demonstrated the ability to lead and supervise, and have
published articles in the field of computer architectures.
Salaries are from $59,215 to $76,982.  U.S. Citizenship is required.

Ames Research Center, located in the San Francisco/San Jose area,
is an equal opportunity/affirmative action employer.

Send a detailed resume and publications list to:
Dr. Ellen Ochoa
NASA Ames Research Center
MS 244-4
Moffett Field, CA  94035
[phone]

******************

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

Date: 13 Mar 90 20:56:56 GMT
From: rpi!pawl5.pawl.rpi.edu![e-mail]  (Mitchell E. Gold)
Subject: Repost of "High Flight"


  While searching through some old boxes, I found my program book from
"The Right Stuff" (Warner Bros.,1983).
  The words from High Flight are listed therein with the following:

    John Gillespie Magee, Jr.
  Pilot Officer Magee joined the Royal Canadian Air Force in October 1940, at
age 18.  He went to England to fly Spitfires.  After qualifying, he was piloting
one on a test flight into the stratosphere at 30,000 feet when he got the
inspiration for "High Flight."  Magee was killed in action during a dogfight
December 11, 1941, at age 19.

     Oh, I have slipped the surly bonds of earth
       And danced the skies on laughter-silvered wings;
     Sunward I've climbed, and joined the tumbling mirth
       Of sun-split clouds -- and done a hundred things
     You have not dreamed of -- wheeled and soared and swung
       High in the sunlit silence. Hov'ring there,
     I've chased the shouting wind along, and flung
       My eager craft through footless halls of air.
     Up, up the long, delirious, burning blue
       I've topped the windswept heights with easy grace
     Where never lark, or even eagle flew.
       And, while with silent, lifting mind I've trod
     The high untrespassed sanctity of space,
       Put out my hand, and touched the face of God.


  The final quote in the program book is by Gus Grisso.
  "If we die, we want people to accept it. We hope that if anything happens
to us it will not delay the program. The conquest of space is worth the risk
of life."

--
               Mitchell Gold   \|/   @ The RPI Solarium
   Rensselpolyinstitechnitute  -*-   Troy, NY, USA
                               /|\  [e-mail]

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

Date: 13 Mar 90 21:25:46 GMT
From: skipper![e-mail]  (Mary Shafer (OFV))
Subject: Re: Subscription to AW&ST in UK ?

In article <[e-mail]> [e-mail] (Simon Taylor) writes:

>Does anyone know where one can get hold of Aviation Week in the UK ?

Subscribe to Flight International instead.  It's better, you'll
get it sooner, and it's got Uncle Roger in Straight and Level!

--

Mary Shafer  [e-mail] or ames!skipper.dfrf.nasa.gov!shafer
         NASA Ames Dryden Flight Research Facility, Edwards, CA
                   Of course I don't speak for NASA

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

Date: 13 Mar 90 15:21:47 GMT
From: eru!luth!sunic!mcsun!ukc!kl-cs!nott-cs!piaggio![e-mail]  (Mark E Wickett)
Subject: Voyager and other probes

I don't know if this question has been asked before, but how exactly
does NASA communicate with their probes?

I presume it's some sort of radio broadcast, but it must be encoded etc.
Would it be possible for someone else to send stuff to these probes to
perform some action?

It may a load of dumb questions, but I'm interested in the answers anyway.

            Mark
--
Mark Wickett - [e-mail]    | What the hell do I know?
         - [e-mail]       |   I'm English!

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

Date: 13 Mar 90 18:50:04 GMT
From: ladcgw!hermes![e-mail]  (Frank Mayhar)
Subject: Re: Challenger last words

In article <[e-mail]6>, [e-mail] writes:
> In article <[e-mail]> [e-mail] (David Messer)
>  writes:
> >Yes, the last words recorded were:  "No, I wanted a BUD Light!"  :-)
> You are quite a jerk, aren't you ?
> John Coughlin    Net: [e-mail]   Vox: 613-541-6439   Fax: [phone]

Well, _I_ thought it was at least mildly amusing.  A product of a sick mind,
maybe, but amusing.
--
Frank Mayhar  [e-mail] (..!{uunet,hacgate}!ladcgw!fmayhar)
              Bull HN Information Systems Inc.  Los Angeles Development Center
              5250 W. Century Blvd., LA, CA  90045    Phone:  [phone]

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

Date: 13 Mar 90 16:57:06 GMT
From: cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!haven!uvaarpa!murdoch!astsun.astro.Virginia.EDU![e-mail]  (Greg Lindahl)
Subject: Re: SR-71 at Smithsonian

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

>Question: Is it possible for the general public to see Enterprise/SR-71
>now, or will we have to wait until the official opening of the annex?

As of yesterday it was sitting outdoors at Dulles, and you can see it
from one of the terminals. Has red paint (?) over the windows so that
you can't see inside. My spy also ran into someone claiming to be an
ex-SR-71 pilot near a display inside the airport. Gee, when a program
gets declassified, it really gets declassified :-)

Greg Lindahl
[e-mail]                                  Astrophysicists for Choice.

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

End of SPACE Digest V11 #146
*******************