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Subject: SPACE Digest V10 #260

SPACE Digest                                     Volume 10 : Issue 260

Today's Topics:
            Re: deadliness of environments
            NIST space conference
                HST resolution
              Re: HST resolution
        Looking Down [was: Re: HST resolution]
           Payload Status for 11/17/89 (Forwarded)
              Re: Hubble Space Telescope
           Re: Looking for US launcher family tree
               Re: Mars space elevator
----------------------------------------------------------------------

Date: 16 Nov 89 15:01:00 GMT
From: cs.utexas.edu!usc!samsung!uakari.primate.wisc.edu!uwm.edu!wuarchive!texbell!merch!cpe!hal6000!trsvax![e-mail]
Subject: Re: deadliness of environments


>Given a certain level of basic technology, space is actually a fairly
benign place;<

I am curious to here what you consider "basic technology".  In the wilds of
Antartica, the "basic technology" necessary to conserve heat, obtain water,
and breath is supplied to every human child by its mother. Food gathering
is a bit more complicated, you generally have to locate a rock or a big
stick.

Please don't underestimate the massive amount of infrastructure which will
be necessary to produce a sustainable space colony.  EMphasis on the word
sustainable.  Projects such as Biosphere II in Arizona are but a modest
step in the general direction towards self-sufficient artificial
ecosystems.

Life is infinitely adaptable, and I've no doubt that organisms will evolve
to fill every possible niche, I'm not so sure that our organism will be one
of them.

Space is not a panacea.  When "we" get there, "we" will be the same
squabling lot of ego-centric beings that we are now. With life support
sytems on which all of "our" lives depend on, government will become more
stringent, not less. Responsibility of the individual to the whole will
increase, not decrease.  The "throw away" society will perish or its
members will fade away.

When those guys walked across the land bridge from Siberia to America, they
really could just run off in the woods and "go native".  Neil Armstrong
didn't have that option.

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

Date: Fri, 17 Nov 89 20:32:40 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: NIST space conference


(Somebody posted a request for more information a few weeks ago. This notice
was distributed to all employees today.)

NIST Conference On
  REDUCING THE COST OF SPACE INFRASTRUCTURE AND OPERATIONS
    November 20-22, 1989
    National Institute of Standards and Technology
     (formerly National Bureau of Standards)
    Gaithersburg, MD
    Sponsored by:
      NIST
      Office of Space Commerce/DOC
      The Space Foundation

                                AGENDA

Monday, November 20, 1989

  Orbital Facilities and EVA Session:
      (Co-chairman: Thomas F. Rogers, ETCO, and Dr. Bill Stone, NIST)
    Spacehab Shuttle Module              James Beggs, SpaceHab, Inc.
    Industrial Space Facility            Dr. Maxime Faget, Space Ind., Inc.
    Space Phoenix Project                Thomas F. Rogers, Sophron Foundation
    External Tank Habitat                Dr. Randolph Ware, ETCO
    Aquarius Habitat                     Glen Taylor, NOAA
    Hardsuits, ROVs                      Phil Nuytten, Candive Services, Ltd.
    Hypobaric Physiology                 Dr. R.W. Hamilton, Hamilton Res., Ltd.

  Chemical Launch Vehicle Session:
      (Chairman: Rich Dalbello, Office of Space Commerce, DOC)
    Hybrid Booster                       Jay Kniffen, AMROC
    Air-Launched ELVs                    Dr. Robert Lindberg, OSC
    u-Sats & Secondary Payloads          Douglas Heydon, Arianespace
    Novel Integration Concepts           Ed Bock, General Dynamics

Tuesday, November 21, 1989
  Payloads and Institutional Aspects Session:
      (Chairman: Dr. Cary Gravatt, NIST)
    Robotics and Automation              Joe Engleberger, Transition Research
    Small Satellite Experience           Ball Aerospace
    Payload Sensors                      Carl Schueler, Hughes SBRC
    Small Compartment Costs              Helmut Hellwig, NIST
    Risk Factors & Insurance             John Cozzi, Carroon & Black Inspace
    Technology Transfer                  Mike Miller, C.I.T.
    Quality and Cost                     Curt Reimann, NIST

  Advanced Launch Vehicle Session:
      (Chairman: Ray Williamson, OTA)
    NASP                                 Mike Weeks, NASA
    Shuttle-C Vehicle                    Ed Gabris, NASA
    Laser Assisted Launch                Dr. Jordin Kare, Livermore Nat'l Labs.
    Ram Accelerator                      Dr. Abe Hertzberg, Univ. of Wash.
    Space Ship Experimental              Steve Hoeser, General Research Corp.

Wednesday, November 21, 1989
  Summary Session:
    Orbital Facilities                   Thomas F. Rogers, ETCO
    EVA                                  Dr. Bill Stone, NIST
    Chemical Launch Vehicles             Rich Dalbello, Space Commerce, DOC
    Payloads & Inst. Aspects             Dr. Cary Gravatt, NIST
    Advanced Launch Vehicles             Ray Williamson, OTA

[NOTE: I don't have anything to do with this - I just work here (in the
computer research lab). I'll try to sit in on some of the sessions if my
boss will let me. Any recommendations/requests?]
                                  John Roberts
                                  [e-mail]

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

Date: Fri, 17 Nov 89 19:00:45 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: HST resolution


>From: cs.utexas.edu!samsung!aplcen!haven!uvaarpa!hudson!astsun9.astro.Virginia.EDU![e-mail]  (Greg S. Hennessy)
>Subject: Re: Hubble Space Telescope

>The resolution of HST is [roughly] 20 milliarcseconds. Let us consider
>Alpha centuri. It is about 1.3 parsecs away, this 1 arcsecond will be
>1.3 AU or about 130 million miles. 20 mas will be about 26 million
>miles. This is about 100 times the earth moon distance. I would
>consider it rather awful reporting myself.

.......................

>>, [e-mail] (Allan M. Bjorklund) writes:
>>
>> I redid the calculations, and came up with the HST being able
>> to resolve a 3000 mile wide object at 39 AU which is about 5.3 light
>> hours, which is the distance to Pluto. But unfortunately, Pluto is only
>> about half that in diameter.

There have been several calculations similar to this posted recently, and
most of them seem to be off (with respect to my calculations) by roughly
a factor of 1.5-2. My reasoning is as follows:

With 60 seconds of arc in an arcminute, 60 minutes in a degree, and 360
degrees in a full circle, an angle of 20 milliarcseconds makes up
1/10800000 of a full circle. To determine the width of the projection of a
small angle at a given distance, you can compute the length of the
corresponding arc along the circumference of a circle at that distance,
or the height of a right triangle with the given angle and the base equal
to the distance. These will be very close because the angle is extremely
small. To compute the arc, the total circumference of the circle is
2 * pi * d, so the length of the arc will be 2 * pi * d / 10800000. To
compute the height of the triangle, use the formula h = sin(theta) * base.
Since for very small angles, the sine of an angle (in radians) is very close
to the value of the angle itself, and the angle is 2 * pi / 10800000, the
height is approximately 2 * pi * d / 10800000. Thus, by both of these methods,
the width of the projection ~= d * 5.818E-7.

Applying this formula to the two reference equations, the resolution at
1.3 parsecs (at 1 parsec = 206265 AU), is about 14.5 million miles, and
the resolution at 39 AU is about 2100 miles.

Would someone please check the figures? I may have misinterpreted some
of the initial assumptions.

It is my impression that the intended method for location of large planets
around stars is to use spectroscopy to look for periodic redshift/blueshift
of the light from the stars, corresponding to the wobble caused by the
influence of the large planets. This would require observation over a
considerable fraction of such a planet's path around its star, which could
take several Earth years.
                               John Roberts
                               [e-mail]

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

Date: 18 Nov 89 01:56:59 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: HST resolution

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

>It is my impression that the intended method for location of large planets
>around stars is to use spectroscopy to look for periodic redshift/blueshift
>of the light from the stars, corresponding to the wobble caused by the
>influence of the large planets. This would require observation over a
>considerable fraction of such a planet's path around its star, which could
>take several Earth years.

Spectroscopy is one technique.  Another is astrometry.  There has been
some work on high precision astrometry using ground-based scopes by
Gatewood in Pittsburgh.  He has a nice instrument that uses a Ronchi
ruling to accurately measure the angular separation between stars.
Accuracies in the milliarcsecond range can be achieved from the ground,
given enough time.

As you would expect, from space you can do a whole lot better.  The
Astrometric Telescope Facility (?) would cost maybe $200-300 M.
It could achieve resolution in the *micro* arc second range --
on the order of the angle subtended by an atom held at arms length!
Jupiter-sized planets would be detectable by this instrument out
to thousands of light years; even the motion due to earth-sized
planets could be detected for nearby stars.

NASA was trying to get the ATF put on the space station -- a
perversion of science, IMHO.  The thing should obviously be a
free-flyer -- a vibrating space station is no place for such a
sensitive instrument.  Since the station was scaled back, there's no
place to put the ATF, and I haven't heard anything about it, so it's
probably been knifed.

An aside -- I hear that Hipparchos is showing little if any degradation
in its solar panels, so it may be able to operate for 30 months,
salvaging much of the mission.

    Paul F. Dietz
    [e-mail]

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

Date: 18 Nov 89 00:45:28 GMT
From: bbn.com![e-mail]  (Nichael Cramer)
Subject: Looking Down [was: Re: HST resolution]


>From: cs.utexas.edu!samsung!aplcen!haven!uvaarpa!hudson!astsun9.astro.Virginia.EDU![e-mail]  (Greg S. Hennessy)
>The resolution of HST is [roughly] 20 milliarcseconds. Let us consider...

Hmmm...

So this works out to a resolution of

   (/ (/ 20.0 1000.0) 206265)

   = 9.6962644e-8 radians.

So, if we put the HST into low earth orbit [say, for round figures,
1000 miles = (* 1000.0 5280.0 12.0) = 6.336e7 Inches] and we
pointed the satellite *down* at the earth, we would get a resolution
of:

   (* 9.6962644e-8 6.336e7)

   =~ 6 Inches.

Hmmm... Not bad.

(But surely they wouldn't do something like that.   ;)

NICHAEL

Let's see... if we were in orbit at only *100* miles....

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

Date: 18 Nov 89 00:42:01 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Payload Status for 11/17/89 (Forwarded)

Daily Status/KSC Payload Management and Operations 11-17-89


- STS-31R HST (at VPF) -

ECS support continued for functional testing.  The "no shake"
portion of the functional test was successfully completed last
night.  Personnel are supporting the continuous VPF environmental
monitoring.

- STS-32R SYNCOM (at VPF) -

The SYNCOM safety verification portion of launch readiness test
was completed yesterday.  SYNCOM cleaning and contamination
inspection was completed last night.  The canister was moved into
the VPF airlock in preparation for Saturday's SYNCOM transfer.
The remainder of the closeout activity and the configuration of
the test cell is planned for today.

- STS-35 ASTRO-1/BBXRT (at O&C) -

IPR troubleshooting continues.  Pallet panel patch was painted on
panel #12.  OSP mates were worked yesterday and will continue
this morning.  Preps for cruciform installation began after a
helicoil was changed out.

- STS-40 SLS-1 (at O&C) -

Water servicing GSE preps and validation continue.  Rack mods
continue today.  Yesterday during eddy current inspection two
gouges were revealed and are under engineering evaluation.

- STS-42 IML (at O&C) -

Bio rack structural mod work is in progress.  Eddy current
inspection was conducted and no defects were found.

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

Date: 17 Nov 89 13:50:38 GMT
From: amara![e-mail]  (S. Khai Mong)
Subject: Re: Hubble Space Telescope

In article <[e-mail]> [e-mail] writes:

>  As far as long base-line interferometry is concerned, I did some
>  calculations, and, going back to the continent-on-a-planet-
>  orbiting-A.-Centuri problem, two HST's in 3000km high orbit 180
>  degrees apart would resolve North America at 4.3 light years. Going to
>  a higher orbit would increase the resolving power, but you have to
>  have some pretty impressive computer facilities to use visual LBI.

It's just not a matter of computer facilities.  The technology just
isn't here yet.  We would need *extremely* accurate clocks to
synchronize the two telescopes and time individual light waves with
those clocks.  Or (is it *AND*?) we would need to position those two
telescopes relative to each other accurate to within one wavelength of
light or less.  Both of which are impossible with current technology.
That is why there is no visual VLBI being done now even here on the
earth.  I did read somewhere sometime ago about a multi-telescope
facility somewhere being used for interferometry, but if I remember
it, they had to site the telescope so accurately with respect to each
other and the light for the telescopes was piped (really reflected) to
some central location.
--
Sao Khai Mong:   Applied Dynamics, 3800 Stone School Road, Ann Arbor, Mi48108
[phone] (uunet|sharkey)!amara!khai  [e-mail]

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

Date: 17 Nov 89 18:01:19 GMT
From: frooz!cfa250![e-mail]  (Jonathan McDowell)
Subject: Re: Looking for US launcher family tree

From article <[e-mail]>, by [e-mail] (Henry Spencer):
> Titan II, ... The last Titan-Agena flew only a few months ago.
> Titan III is a Titan II with two great big solid strap-ons.

 Minor correction: Agena flew on strapon-less Titan IIIB and Titan 34B, not on Titan II.
The distinction between II and III is not the presence of the strapons
but the fact that III was specifically designed for space missions.

> The USAF's Thor IRBM ....
> was turned into a small launcher with the addition of a modest upper
> stage.

You then talk about Delta, which was originally the name of a Thor upper stage;
but there was a whole other family of Thor-based launchers, the Thor Agena series,
which was the major launch vehicle of the 1960s.

-Jonathan McDowell

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

Date: 17 Nov 89 12:38:03 GMT
From: sei![e-mail]  (Robert Firth)
Subject: Re: Mars space elevator

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

>Mars has one large disadvantage too: the moon Phobos orbits within the bounds
>of its synchronous orbit. I don't think there's any point along Mars' equator
>that Phobos doesn't eventually pass over, which would certainly affect the
>performance of the space elevator! :-) This problem was discussed in Fountains
>of Paradise by Arthur C. Clarke. The proposed solution was to set up a
>carefully-controlled vibration in the elevator, which would cause it to
>move out of the way as Phobos passed by.

Um... wouldn't it be a lot simpler to move Phobos?

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

End of SPACE Digest V10 #260
*******************