Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_1/V11_165.TXT

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Subject: SPACE Digest V11 #165

SPACE Digest                                     Volume 11 : Issue 165

Today's Topics:
             space news from Feb 19 AW&ST
      Re: Fun Space Fact #1: Launcher Development Costs
               Space Studies Institute
            Re: Challenger Report question
            Re: More space station news...
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
              Re: Strange flash of light
Feynman's Rogers Commision Report (Was Re: What was Challenger really doing?
               Re: Spacecraft on Venus
        Re: Attitude control system (ACS) for the HST
----------------------------------------------------------------------

Date: 20 Mar 90 02:31:38 GMT
From: csusac!csuchico.edu!petunia!usc!cs.utexas.edu!mailrus!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from Feb 19 AW&ST

NASA claims Shuttle-C cannot be justified economically for space station
construction... but NASA Advisory Council report says this is partly
because NASA is overestimating Shuttle-C costs, by bundling in purchase
of facilities and hardware that will be needed for the regular shuttle
fleet anyway.

LACE/RME mission (SDI Delta) goes up Feb 14.  Deployment of the two
satellites required a total of seven ignitions of the Delta second stage,
a new record.  LACE is to measure atmospheric distortion of low-power
laser beams coming up from the ground; RME is to demonstrate use of a
satellite mirror to reflect a laser beam from one ground station to another.
This is probably the last SDI Delta for a while, given funding cuts.

Galileo Venus flyby successful.  Minor software problems with a camera
shutter operating unintentionally have been resolved.  Fuel consumption
is looking good, with revised estimates showing a positive margin with
both asteroid encounters and a full schedule at Jupiter.  The IUS launch
was more accurate than expected, Galileo's thrusters are about 2% more
efficient than preliminary estimates, and lengthy analysis of planned
maneuvers has turned up some small economies.  The Gaspra encounter is
now firm; decision on the Ida encounter will be made after Gaspra.

Replacement crew go up to Mir Feb 11.  Launch of the Kristal technology
module is expected late in March, and the new crew will do a good deal
of work in it.  Some estimates suggest the materials work will be
valuable enough to show a net profit for this mission.

Matra examines a dedicated military comsat for joint use by France,
Italy, and Spain.  The French Telecom series and Spain's Hispasat,
both being built by Matra, will carry military transponder packages,
and there may be enough demand to justify a dedicated satellite later.

The Pacific TDRS has suffered a small but troublesome failure.  Normally
each of the two large antennas can independently switch between linear,
left-circular, and right-circular polarization.  The left antenna seems
to have blown a fuse, and is stuck in left-circular mode.  The problem
is that major customers, including the shuttle, Landsats 5 and 6, and
the Hubble telescope, are fitted for right-circular only.  NASA is
looking into modifying the shuttle orbiters to use left-circular.  The
old spare TDRS might also be moved to the Pacific slot.  Neither of
these steps will be taken until the problem is studied in more detail.

[Another light week.  Just as well, I'm starting to get caught up.
Which in turn is just as well, since I've still got the issues I missed
(due to the December subscription foulup) to do.  They will be terser
than usual, but I'm going to try to squeeze them in.]
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 19 Mar 90 19:43:01 GMT
From: [e-mail]  (SERRE GLENN)
Subject: Re: Fun Space Fact #1: Launcher Development Costs

In article <[e-mail]> [e-mail] writes:
>
>Fact 2:  This redesign made the Shuttle much more complex.
>

How is the present design more complex than the original design of the shuttle?
More engines, higher Isp, more computers, what?

--Glenn Serre
[e-mail]

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

Date: 20 Mar 90 05:48:28 GMT
From: usc!samsung!munnari.oz.au!cluster![e-mail]  (Raymond Lister)
Subject: Space Studies Institute

After the recent talk of mass drivers, rail guns etc, I thought a
reminder about the Space Studies Institute might be timely.

The Institute was founded by Gerard O'Neill.  He made his name as a physicist
by inventing the storage principle for colliding particle beams.  In the
early '70s he started thinking about the construction of large space
colonies. The colonies would be constructed as much as possible from lunar
materials, launched by mass drivers.

The Space Studies Institute's activities are geared towards the colonization
of space.  These days its projects include:

1. Studies of Solar Power Satellites.
2. The design and construction of the Lunar Prospector, a small spacecraft
   that will provide a chemical map of the moon, and search especially for
   ice at the lunar poles. The spacecraft will use an Apollo surplus
   gamma-ray spectrometer, supplied by NASA, and will be launched from a
   shuttle.
3. Processing of lunar materials: which has reached the point of construction
   of a (ground based) pilot plant.  This work proceeds in conjunction with
   Alcoa/Goldsworthy, and McDonnell Douglas.
4. Studies of uses for the shuttle external tanks.

  ... and others.

The SSI depends on private donations for its work.  If you're tired of moaning
about how the politicians won't support space exploration enough, and you'd
like to know how you (yes, you!) can help directly, write to:

Space Studies Institute
PO Box 82
Princeton
New Jersey 08542-9938
USA

As my own membership shows, they're happy to accept non-US citizens.

Raymond Lister
Department of Computer Science
University of Sydney
NSW  2006
AUSTRALIA

Internet: [e-mail]
CSNET:    [e-mail]
UUCP:     {uunet,hplabs,pyramid,mcvax,ukc,nttlab}!munnari!cs.su.oz.AU!ray
JANET:      munnari!cs.su.oz.AU!ray@ukc (if you're lucky)

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

Date: 20 Mar 90 01:11:00 GMT
From: swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!uxa.cso.uiuc.edu![e-mail]
Subject: Re: Challenger Report question



I know the famous "chances of distaster" report written by the big
F. is FTPable...is this the one you are talking about?  The disaster
report is available on ames.arc.nasa.gov (dont have it in numbers).
Ames is neato is you like space stuff.  Check in directory /space or
/pub/space I think.

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

Date: 20 Mar 90 17:36:39 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: More space station news...

Today's (3/20) NY Times has an article reporting on reaction
to yesterday's disclosure of the space station's problems.  Some
tidbits:

Russ Nelson, chair of the House space committee, said the
study was troubling.  "It raises legitimate questions of
operational cost, and we have raised them, too."  He said
NASA had a history of being "recalcitrant to do something
about these operational costs," pointing to the space shuttle,
of which the expense and complexity of operating turned out
to be "much greater than ever projected."

NASA's statement yesterday said the internal study was unduly
pessimistic and relied on a "worst-case scenario".

But the NY Times says a NASA expert familiar with the study
said it was actually too optimistic and that its estimate
of 2,200 hours was growing as researchers identify more parts
as vulnerable to failure.  He said the contractors' estimates
of the reliability of individual parts were "pretty accurate".

The NASA statement also said the space station could be redesigned
in a minor way that could reduce the maintenance problem, "without
disrupting the schedule, cost or overall architecture of the
program."

But the NASA expert said a radical redesign would probably be needed.

"In the end, they're going to have to decide that the station
as designed is unbuildable," he said.  "It's the consensus here
that somebody let something slip."

The article quotes a congressional aide as saying congress does
not want to be burned again, as it was with NASA's underestimation
of the space shuttle's operational problems.
----

I find the difference between the NASA PR and the engineer's comments
revealing.  You still think a NASA space station is a good idea, Henry?

    Paul F. Dietz
    [e-mail]

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

Date: 19 Mar 90 14:19:00 GMT
From: van-bc!rsoft!mindlink![e-mail]  (Ed Meyer)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

Just tuned in to this topic and, boy, what creativity!

Seems to me that what we're heading for is a reusable/recoverable launch
platform that, like an elevator, can lift the payload to a significant height
from which launch-point is achieved.  Then, we recover the lifter (in tact) to
do it again.  Of course, adding significant velocity toward orbital velocity
would be nice, but it's got to be a very small portion of final orbital
velocity.

Any-who, regardless of my ignorance on this subject, other's creativity is
really enjoyable  :-)

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

Date: 20 Mar 90 18:30:32 GMT
From: cunixf.cc.columbia.edu!lamont![e-mail]  (bill haines)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

In article <[e-mail]>, [e-mail] (Wm E. Davidsen Jr) writes:
> In article <[e-mail]> [e-mail] (Norman C. Kluksdahl) writes:
>   My guess is that something other than a 747 would be a better fit, and
> one of the cargo planes designed for CG shift and operation with the
> tail open might be a starting point. How about a telescoping launcher?
> | No doubt such an arrangement would shatter every conceivable limit
> | on the CG limits of the aircraft.  Plus, you have to consider that
> | the force necessary to stop about 25 metric tons has to come from
> | the aircraft.
>   Given that we have planes which are designed for other conditions than
> a 747, your objection are correct but not damning. Until I can get
> better info on something like a C130 I won't claim that it can be done,
> bill davidsen - [e-mail] (uunet!crdgw1!sixhub!davidsen)

There is always a C5a or C5b which are larger
and have higher payload capacities.

Also since the Air Force is putting a bunch of
SR-71 into mothballs how about taking out
all the spying equipment and putting in
an even smaller coilgun as the Blackbird
flies much higher and a "little" bit faster...


just an idea

Bill

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

Date:     Tue, 20 Mar 90 8:20:11 CST
From: Will Martin <[e-mail]>
To: [e-mail]
Cc: [e-mail]
Subject:  Re: Strange flash of light

Unfortunately, my copy of the Paranet Digest (#177) that contained the
basenote to this followup was truncated in the middle of that particular
posting!   :-(   Talk about conspiracies... I am CC'ing to the SPACE
list in case the cause of the flash was space-related.

Anyway, apologies if any of what I say duplicates that original posting:

I and a couple of my guests saw the same flash of light Saturday night
(Mar 17, approx 9:30 PM CST).  However, we saw it through windows and were
not looking directly at the sky or the source, so only had a brief
flicker of impression.  The color appeared to me to be *blue-white*,
like lightning, and not the "yellow/white" mentioned.  Of course, the
transmission through glass may have changed the apparent color.
However, the news reports we heard later referred to it as "white".  It
was mentioned on all the local St. Louis TV stations during their
evening newscasts at 10 PM or thereabouts, mostly in the weather
segments but also as a regular news item.  There were many references to
NORAD and to the National Weather Service having been contacted, but
those organizations had no explanations or comments at that time.  The
flash was reported from all over the Missouri/Illinois area, according
to the news reports, but no mention was made of its visibility from
other locations.

Some reports said it was only a single flash, while others described a
"flickering" or multiple flashes. I saw only a single flash.

There was some speculation about it being a re-entering piece of space debris
or a meteor, but nothing definite. No UFOs were mentioned that I heard.
Then, later, I heard another, more elaborate report in which the flash was
linked to a fire started in a farmer's field by something falling out of
the sky. This was only heard once, and I have no idea of its accuracy.
(I do not remember the location cited for that.)

After seeing the flash thru the window, I went outside and looked at the
sky. It was clear and cloudless, as far as I could determine, which made
the "lightning" idea I at first had seem wrong. (Actually, there were more
stars visible than is usual these days in the city with all the haze and light
pollution... :-() I then thought it might have been a streetlight bulb
blowing out, but then my guests said they had seen it through the windows
on the opposite side of the house, and that argued against that. Later, then,
I heard the news reports and realized it was more widespread.

I heard another followup news report Sunday that stated that there still was
no official explanation for the flash. I have not seen any newspaper or
other written reports of this incident. I encourage anyone who has written
articles on the subject to scan them in or type in a summary and send it
to the group.

Regards, Will Martin

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

Date: 20 Mar 90 01:05:48 GMT
From: [e-mail]  (Richard Johnson)
Subject: Feynman's Rogers Commision Report (Was Re: What was Challenger really doing?

[e-mail] writes:

] Mike Hewett writes:
] >I understand that Feynman wrote an addendum to the report that
] >put stronger blame on the parties involved.

] The Rogers Commission Report is five volumes long.  What Mike read was
] volume 1, the Executive Summary.  This part was written for the policy
] makers, media people, general public, etc. who most likely don't have
] a lot science/engineering background.  Volumes 4 and 5 are the complete
] transcripts of the public hearings.  Volumes 2 and 3 are the technical
] appendixes where all the nitty-gritty details are.  Feymann's personal
] report is Appendix F in volume 2.  If you need it, the government document
] number for it is Pr40.8:Sp1/R29/V.2.

Feynman's personal report on the reliability of the shuttle also appears in
his book "_What Do You Care What Other People Think?_" (Bantam, New York,
1989 - ISBN 0-553-34784-5).  Part two of the book is an account of his
adventures as a member of the Rogers Commission.

| Richard Johnson                           [e-mail] |
|    CSC doesn't necessarily share my opinions, but is welcome to.     |
|  Power Tower.>.Dual Keel.>.Phase One.>.Allison/bertha/Colleen.>.?... |
|   Space Station Freedom is Dead.  Long Live Space Station Freedom!   |

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

Date: 21 Mar 90 00:44:23 GMT
From: sco![e-mail]  (John DuBois)
Subject: Re: Spacecraft on Venus

In article <[e-mail]> [e-mail] (Russ Cage) writes:
+
+Now all that is necessary is a power supply.  These are all devices
+which (will) require electricity, what will work at Venus temps?
+Are Peltier junctions available for RTGs which can run at 800 F on
+the *cold* side?  What about rectennas to receive beamed power from
+a (higher, cooler) balloon-borne probe?  (If we can make an 800 F
+transistor, we can make an 800 F Schottky diode, I bet.)

     How about a thermoelectric generator that uses the temp. diff. between
Venus surface ambient and and a cold source?  I seem to recall that some
Venus landers (Soviet?) boil off their remaining thruster fuel just before
atmosphere entry to cool down the spacecraft to extend its life on the
surface.  A "hot" lander wouldn't need it for that purpose; perhaps the
remaining cryogenic fuel (of course, you'd need to ensure that plenty remained)
could be used as a cold reservoir.  Probably not too efficient, but at least
you could be sure that your power source wouldn't *add* heat to the lander.

    John DuBois

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

Date: 19 Mar 90 20:10:48 GMT
From: snorkelwacker!usc!elroy.jpl.nasa.gov!aero![e-mail]  (Miriam H. Nadel)
Subject: Re: Attitude control system (ACS) for the HST


Of course there is no contradiction between the various claims of the
advertisers.  Reaction wheels are used for attitude control and, in fact,
the reaction wheel design for the HST apparently required considerable
efforts towards appropriate dynamic isolation to avoid introducing jitter.
(I know this because one of the projects I work on has adapted their
reaction wheel design in order to reduce our jitter.)

Star trackers are rarely used for attitude control but are used for
attitude determination.  That is, the attitude computed from star tracker
measurements is not fed back to the attitude control system (which instead
takes its measurements from reaction wheels, gyros, sun sensors and/or earth
sensors).  This is appropriate when you need to know where you're pointing
more precisely than you need to point.


Miriam Nadel
--
Not one of the 85% of Americans who didn't see Halley's comet.

[e-mail]

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

End of SPACE Digest V11 #165
*******************