Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO425.TXT

Internet Message Format | 1993-07-13 | 14KB

Date: Mon, 16 Nov 92 05:00:03
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #425
To: Space Digest Readers
Precedence: bulk


Space Digest                Mon, 16 Nov 92       Volume 15 : Issue 425

Today's Topics:
                                COSTAR
               N-1 giant Moon rocket photo in *AvLeak*
                          Please clean up |
                    Putting telescopes on the moon
                         Shuttle replacement
                Shuttle replacement, STS-52 half-full
               Shuttle Status for 11/13/92 (Forwarded)
                         Space suit research?

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

Date: 15 Nov 92 13:56:50 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: COSTAR
Newsgroups: sci.space

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

> Are they the same company that makes mason jars? (The logo appears to
> be the same.)

They are indeed. Also aluminum cans - next time you see a Coke can,
look for the same, familiar logo. I visited their plant in Boulder,
Colorado, in 1989 summer, as part of a Solar physics summer school held
by the National Center for Atmospheric Research/High Altitude
Observatory. They showed us the CREES satellite, being assembled, and
the technology for the IRAS and other micro-g liquid helium dewars,
which they developed. I'm not sure what this has to do with applesauce
or currants, but who knows, with big corporations?

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

Date: Sat, 14 Nov 1992 21:04:31 GMT
From: Dennis Newkirk <[e-mail]>
Subject: N-1 giant Moon rocket photo in *AvLeak*
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Hartmut Frommert) writes:
>
>Can someone make it a .GIF and upload on a ftp server ?
>--
> Hartmut Frommert                 <[e-mail]>

I know 3 GIF's of the photo showing closeups of portions, and
the complete photo were put on Compuserve a couple of months ago
in the space forum new uploads section I think.

Dennis Newkirk ([e-mail])
Motorola, Land Mobile Products Sector
Schaumburg, IL

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

Date: Sun, 15 Nov 92 15:23 FWT
From: "Andre HECK"                                <[e-mail]>
Subject: Please clean up |

To anyone feeling concerned:

I have subscribed to this space-digest not so long ago and I am appalled
by the quantity of rubbish I have been receiving since. Is no-one
filtering the inputs for this digest? Frankly pollution of information
seems to be an ignored concept here.

There is an enormous duplication of text in the sense that messages
answering others repeat in extenso the contents of the latter ones.
A concise reference would do.

If reports on spacecraft status are perfectly in line with what one
could expect from such a space-digest, the exchange on how to use
slide-rules (v15 #420) is definitely out of place. Please, are we still
kids jumping on line without thinking it over twice beforehand?

I shall maintain my subscription for some time, but if the situation
does not improve, I shall signoff as I am convinced many did before
without voicing their reasons.

Regards. AH.

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

Date: Sun, 15 Nov 92 10:26:10 EST
From: John Roberts <[e-mail]>
Subject: Putting telescopes on the moon

-From: [e-mail] (Roger Arnold)
-Subject: Re: Putting air on the moon
-Date: 13 Nov 92 17:16:46 GMT
-Organization: Intergraph Advanced Processor Division - Palo Alto, CA

-In article <[e-mail]> [e-mail] (John Roberts) writes:
->If that's correct, then a 1000 km array on the moon could potentially give
->a resolution at 10 light years of about 50 km. (Imagine mapping the continents
->on the planets of nearby star systems!) [..]

-Sorry, won't work.  Not unless the individual telescopes in your array
-are pretty spectacular instruments in their own right.

-You need around 10 meters of unobscured aperture, with a mirror
-perfectly figured and smooth to .01 lamda, to keep the light from the
-planet from being lost in the statistical noise of light diffracted
-from the primary.  And even that's only adequate for the dozen or so
-nearest stars.

Well, one good sign: the precision of the HST optical system (primary plus
secondary) is on that order. (Note that I didn't say *accuracy*. :-)
Of course the HST primary isn't that big.

-The problem is that, for a terrestrial planet at optical wavelengths,
-the light any telescope receives from the planet will be ten orders
-of magnitude below (one ten-billionth) the light from the primary.  If
-planet and primary were of equal brightness, a one meter space tele-
-scope could resolve them.  But as it is, it would take nearly perfect
-diffraction-limited optics of ten times that aperture to concentrate
-the planet's light enough to detect it above the far-field light haze
-from the primary.

-But, you ask, so what?  Won't mixing the signals from the combined
-telescopes in the array isolate the light from the planet?  Well, yes
-and no.  You can boost the signal-to-noise ratio by an amount that's
-proportional to the number of telescopes in the array.  That might
-allow you to detect the presence of the planet, where you couldn't
-otherwise.  But unless you start with a pretty clean signal in the
-first place, there will be far too much noise to allow anything like
-imaging of continents.

Would speckle interferometry, or integration of the incoming signals over
very long periods of time (hours to weeks) help with reception? (Other than
the fact that planets move over such time intervals.)

I think you've made your point that the resolution formula can't be extended
out to infinity. I'd be interested in how far it *can* be extended with, say,
100 high-precision 10-meter optical telescopes.

John Roberts
[e-mail]

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

Date: Sat, 14 Nov 92 20:46:28 PST
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space.shuttle,sci.space

Very good article, Mike.

I think you covered all the bases quite well, except that I would like to add
a note or two abosatellite launches. In the best hindsight is 20/20
fashion, I think it was a terrible mistake to offload all those payloads
from the Shuttle in 1986-88. Of our unmanned boosters, only Delta seems to
be operating reliably. It is my opinion that NASA should have continued
using Shuttle for as many payloads as possible, while diverting as much
booster development money as possible into NLS or some other unmanned
launch system. Instead, we got Titan IV, a boondoggle in the finest Space
Shuttle tradition. At least Space Shuttle is flying... and regularly.
How much money has the Air Force poured into that program? And for what,
a new monument at Launch Pad 41? The thing was on the pad so long it got
rusty. Meanwhile, Shuttles are being launched half-empty (i.e., STS-52)
Am I the only one who sees something wrong there?
Titan IV has flown 6 times since June, '89. STS has flown 22 missions in
that time frame. Of course, STS is more expensive. But its already paid
for, and all that money for Titan IV (not including Martin's Titan III
program) has bought us little.
Even old faithful Atlas-Centaur is in a world of trouble, but it's trouble
is mostly due to a Centaur derivative meant for Shuttle. It seems to me
that in 1992, Space Shuttle is offering one of the best returns on
investment in the space community!
-Brian

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

Date: 15 Nov 92 06:05:18 GMT
From: William Li <[e-mail]>
Subject: Shuttle replacement, STS-52 half-full
Newsgroups: sci.space.shuttle,sci.space

rticle <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>
>rusty. Meanwhile, Shuttles are being launched half-empty (i.e., STS-52)
>Am I the only one who sees something wrong there?


As someone who worked on STS-52, I feel obliged to comment on this perception
that STS-52 was launched half-empty.  I worked Space Vision System (SVS)
support, SVS being one of 7 experiments flown as part of CANEX-2.  SVS uses
the orbiter's own cameras to track payloads and other artificial targets,
providing the human operators with highly accurate, real-time positional and
velocity feedback in, for example, remote manipulator operations or orbiter
docking procedures.  STS-52 was a characterisation flight for the SVS,
designed to examine the interactions of the orbiter system with the mature
(~20-30 yrs) technology of the SVS.

As part of the SVS operations, the MS's Lacy Veach and Tammy Jernigan used
the SVS to provide feedback as they maneovered a lightweight satellite
(the Canadian Target Assembly, or CTA) around and above the payload bay.
(The CTA was a black domino-looking thing, about 4' wide, 8' high, and 19" deep)
These operations were designed to demonstrate various skills which would be
required for Space Station Freedom assembly.  One of these operations
consisted of berthing and unberthing the CTA from its cradle.

The inputs to the SVS consist of video from the orbiter cameras, the primary
cameras for STS-52 ops being cameras Alpha and Delta, the two forward bulkhead
cameras.  It would have rendered operations difficult, to say the least,
if the view from the forward bulkhead cameras of the cradle was obstructed
by, say, a sun shield containing another satellite for launch.  The aft (rear)
cameras could not be used for this particular unberthing because their view
was obstructed by the LAGEOS sun shield.  As well, such obstructions would
have forced operations to move out much further above the payload bay because
of remote manipulator flight rules about proximity to structures.  This change
in procedure would have limited our ability to study phenomena such as orbiter
flex due to thermal gradients in orbit. (the shuttle is not a perfectly
rigid platform)

In short, the Space Vision System operations required the elbow space in the
payload bay.  Unfortunately, when no SVS ops were going on, the sim views
of the orbiter payload bay showed a stowed remote manipulator system and
a tiny black domino (the CTA) stowed in its cradle attached to a GaS beam.


>is mostly due to a Centaur derivative meant for Shuttle. It seems to me
>that in 1992, Space Shuttle is offering one of the best returns on
>investment in the space community!
>-Brian

I agree.  These are very exciting times to be involved with the space
business.  I think the Space Shuttle program is back on track.


William Li

Disclaimer:
The comments made above do not constitute an official statement from the
Canadian Space Agency, although a similar-sounding statement was issued by
the Canadian Astronaut Program in response to the same critique of STS-52
(ie, half-empty).  I am now back at school, and no longer work for the
Canadian Space Agency.  These comments also do not represent the views,
express or implied, of anyone at the School of Engineering Science at
Simon Fraser University, at which I am a student.  They are a result of
my own observations and deductions following a year of work for CSA on
the SVS.  Any feedback can be directed to me through UseNet or by email
at [e-mail].  This article was not intended to flame any one,
thing, or small animal.

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

Date: 15 Nov 92 04:27:06 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Shuttle Status for 11/13/92 (Forwarded)
Newsgroups: sci.space

STS-52, STS-53, STS-54, and STS-55.
Well, they'll be in order (as things stand now) but they're still one flight
off. STS-52 was Flight 51. I think, next summer with the ACTS mission, we'll
get the program back on track... in order and on time. Of course, then the
Hubble Revisit (STS-63, moved forward on the schedule) will throw us off.

I believe STS-44 a year ago was actually the 44th flight. We may never see
such a coincidence again!

-Brian

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

Date: 15 Nov 92 05:31:27 GMT
From: Pat <[e-mail]>
Subject: Space suit research?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:
>-was a Very Good Thing.
>
>Thanks for the confirmation. 8.4 psi sounds plausible - 10.2 seemed a little
>high, since they always depressurize somewhat in preparation for an EVA.
>
>Anyone recall whether there was an unusually high rate of equipment
>failure for that flight that might be associated with the lower pressure?
>(Other than the fax machine jamming as usual, of course. :-) I remember
>that one or more of the cargo bay lights burned out, but that wouldn't
>be pressure-related.
>

What's the big push for a earth normal type atmosphere?
apollo, etc, ran fine on low pressure pure O2,  does better pressure
greatly improve cooling.  or are there long term bio effects????

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

End of Space Digest Volume 15 : Issue 425
------------------------------