Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_3/V16NO365.ZIP/V16NO365

Internet Message Format | 1993-07-13 | 21KB

Date: Thu, 25 Mar 93 05:42:37
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #365
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 25 Mar 93       Volume 16 : Issue 365

Today's Topics:
                                <None>
                Al to isometric crystalline C..diamond
                         Dallas Boring Snooze
               Flame Derby (was Re: Luddites in space)
                          How to cool Venus
          Rocket clones: reduce risk of introducing new tech
                             SSF_REdesign
                          Water Simulations
    Water Simulations (Was Re: Response to various attacks on SSF)
                  Why use AC at 20kHz for SSF Power?

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Date: 24 Mar 93 22:44:08 GMT
From: [e-mail]
Subject: <None>
Newsgroups: sci.astro,sci.physics,sci.space

In article <[e-mail]>, [e-mail] (FRED W. BACH) writes:
> In article <[e-mail]>, [e-mail] (Mohib N Durrani) writes...
>
>    [ a lot of really intense stuff deleted ]
>
> #  Look For The CRESCENT MOON ( HILAL ),     --- >>>                         )
> #   It Is One Of THE MOST BEAUTIFUL OF CREATIONS;  ---- >>>>               )
> #    Then Offer An INTENSE PRAYER To The ONE CREATOR, ---- >>>>           )
> #     All Sincere DEVOTIONS Are Surely ACCEPTED.  --- >>>               )
>

On Monday afternoon (in Maryland) I heard on the radio a report that
an announcement came from Saudi Arabia that the crescent moon _had_
been sighted (evening had fallen in that part of the world).  The
radio also said that since it had NOT been sighted that evening
in Iran (futher east), those there will continue to observe Ramadan
for (at least) one more day.  However, my references say that New Moon
had not even occurred until later Mon night/Tues morn (MAR 23 07:14 UT),
and Ottwell's book said that sighting of the crescent would be very
unlikely in the eastern US even on Tuesday night.

I think this was consistent with the original posting (now vaporised
on my system).  So how can it be sighted a whole day earlier even
further east?  Has anyone else heard of such announcements and whether
they were officially accepted or retracted or if not, how did they
move the moon around?

Although I believe this method of calling months (CALendar stuff)
is mostly arbitrary, so it doesn't really matter much to non-followers
of the tradition, if such rules are used, why are they not done in
a consistent manner?  Or was the report just a mistake by the radio
station?  If so, perhaps we need more education for the media.

Just curious,
Wm. Hathaway
Baltimore MD

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

Date: Thu, 25 Mar 1993 03:16:48 GMT
From: Donald Lindsay <[e-mail]>
Subject: Al to isometric crystalline C..diamond
Newsgroups: sci.space

[e-mail] ("S.K. Whiteman") writes:
>         to artificial diamonds.  I was wondering if
>         there has been any technical info available on this
>         topic.

Scientific American covered this in the last year or so.

Since then, there have been various announcements .. like the people
who sell molded diamond.
--
Don        D.C.Lindsay    Carnegie Mellon Computer Science

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

Date: Wed, 24 Mar 1993 20:03:52 GMT
From: Dillon Pyron <[e-mail]>
Subject: Dallas Boring Snooze
Newsgroups: sci.space

For those of you in the Dallas area, or who (foolishly) read the Snooze (aka
Dallas Morning News), check out the Wed. TODAY section.  I've already called,
they are both mortified and concerned, since their sources indicate the
information was correct:

A graphic on the progress of women shows
1978 - Sally Ride is the first woman in space

--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
[phone] (when I'm here)     |
[phone] (when I'm home)     |God gave us weather so we wouldn't complain
[e-mail]          |about other things.
PADI DM-54909                     |

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

Date: 24 Mar 93 12:57:01
From: Steinn Sigurdsson <[e-mail]>
Subject: Flame Derby (was Re: Luddites in space)
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:

   In article <1op22q$[e-mail]>, [e-mail] (George William Herbert) writes:
   > Nick: hold your breath for a minute and don't post anything tomorrow.

   > Dennis: hold your breath for a minute and don't post anything tomorrow.

   > You two are both smart enough not to have to get into flame wars every
   > few months...

   Maybe they should both take a break and gang up on Allen.

   What do you think, George, are pat and Steinn promising new contenders
   in the Flame Derby?

Eek, and here I've been holding my breath for a whole day now!
Definitely time to stop - no point anyway, I can never equal the
ideological purity of previous champions ;-)

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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

Date: Wed, 24 Mar 1993 19:07:11 GMT
From: James Davis Nicoll <[e-mail]>
Subject: How to cool Venus
Newsgroups: sci.space

    Could one of the thermodynamics-literate people on the net make
a guesstimate as to how long it would take for the the Venerian  atmosphere to
cool enough  so that the various components of the atmosphere liquified/
solidified, given a sudden lack of illumination from the sun? I have a
gut feeling it would take an inconvenient amount of time for Venus to
cool, but I trust math over gut feelings.

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
> Trying for an intermediate yield, between the Soviet bomb and the Sun,
>presents formidable technical challenges.


    Now, that's sig.file fodder.

                            James Nicoll

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

Date: 24 Mar 93 22:47:55 GMT
From: Henry Spencer <[e-mail]>
Subject: Rocket clones: reduce risk of introducing new tech
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>As witness Pegasus, it *is* possible to create a new payload class with
>>a new launcher.
>
>Scout, and Ariane multiple satellite launch systems, had already created
>the Pegasus payload class...

Then why weren't any being launched?  The number of *small* satellites
carried up on Ariane to date can be counted on your fingers, and the
number of launches carrying them can be counted on your thumbs.  Scout is
moribund if not dead.  Pegasus's order backlog already exceeds the total
number of such payloads flown in the last decade.

When people plan for such missions, the nominal launcher is almost
invariably Pegasus.  Once in a while somebody mentions Scout.  Launch
opportunities for small payloads on Ariane are scarce as hen's teeth.
It was Pegasus that made this payload class real.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 24 Mar 1993 14:15 EST
From: "David B. Mckissock" <[e-mail]>
Subject: SSF_REdesign
Newsgroups: sci.space

In article <[e-mail]>,
[e-mail] writes...

>   Max Faget and Joe Allen of SII were 2 of the first  people
>named to the Shea group looking at SSF re-design.

Are you sure Joe Allen is a member of the team? The list
floating around headquarters has four non-NASA /
non-International Partner folks on the SSF re-design team:
     Mr. Mike Mott
     Dr. Max Faget
     Adm. Tom Betterton
     Mr. Ed Nowinski

Everybody knows Faget, but some of us are in the dark about
where the other three guys came from (a search in the
copy of "Who's Who" in the library didn't turn up anything).

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

Date: 24 Mar 1993 15:46 EST
From: "David B. Mckissock" <[e-mail]>
Subject: Water Simulations
Newsgroups: sci.space

In article <[e-mail]>,
   [e-mail] (Allen W. Sherzer) writes...


>I think water tanks and practicing on them is
>a great idea. However, to assume that we can corelate actions in
>the tank to the actions needed to assemble a large space structure
>(like Freedom) in free fall is foolish.
>
>The bottom line remains that we have nowhere near the EVA
>experience base to practice any but the most simple EVA activities
>with any degree of confidence.

and, Dennis had written:

>>The primary problem that was faced on the Intelsat mission is
>>that the tank simply cannot accurately mimic the moments of
>>inertia of large structures in orbit.

To which Allen brilliantly responds with:

>You mean like space stations? Congrats Dennis, you have found a
>problem with Freedom construction: the tanks cannot provide a
>suitable simulation for the construction of Fred.

I guess Allen's thought process is: "Fred is very big. Fred is
made up of lots of big pieces. Intelsat was big. The astronauts had
problems grabbing Intelsat. Ergo, astronauts will have problems
assembling Fred. NASA, in its typical stupidity, does not see the
obvious connection between big things, like Intelsat and Fred and,
compounding our stupidness, we don't realize that you can't mimic
the moments of inertia of large structures in water tanks."

Two points come to mind:

#1 The Canadian Mobile Servicing System (MSS)
In case you have forgotten, CSA is developing the MSS for Fred.
NASA considers the MSS part of our "critical path,"
which means that it
is an indespensable part of the assembly and maintenance procedures
for SSF. The MSS includes a robotic arm (SSRMS, Space Station
Remote Manipulator System), which, in conjunction with the
Shuttle arm, is used to assemble the 'big'
parts of SSF (like the modules & the PIT truss segments). SSF
is *NOT* constructed with crewmembers moving by hand things like
the 27 foot (8.4 meter), 35,600 pound (16,148 kg) hab module.

Let's walk through the on-orbit installation of the HAB.
Shuttle launches with the HAB in the bay, Orbiter docks with
SSF. Bay doors open, Shuttle arm used to take the HAB out
of the bay. Shuttle arm hands off the HAB to the Station
arm. Station arm plugs the HAB into Node 1. Astronaut
goes EVA, inspects the mated joint, returns to the
inside. HAB Assembly complete.

My my, we have a real complicated EVA procedure there,
don't we?

#2 Astronauts participate in the tank tests.
When we practise the EVA's in the water tanks
at JSC & MSFC, we don't
just sign-up divers from the local diving club. We utilize
astronauts, who HAVE ON-ORBIT EVA EXPERIENCE. Thus, we are asking
somebody who "has been there" to gauge the acceptability of our
suggested EVA tasks.

This is a key point. At the sub-team meetings for the WP-04 CDR
that occured late last month, representatives from the astronaut
office were in attendance to defend the Review Item Discrepancies
(RIDs, in NASA-ease) written by their organization. I sat in
when several of their RIDs were discussed in detail in the
Operations sub-team. To give you examples of their issues, they
were concerned with the susceptability of the solar array mast
cannister to accidental EVA kick-loads (the idea is an
astronaut might accidently kick a hole in the side of the
cannister), they noted that one of our
contingency EVA procedures required a tool to operate longer than
it's spec value (a word in our defense, nobody had told us the
spec value for the tool),
they worried about interference with cable
bundles, because a drawing showed a cable bundle near an EVA
translation path. All-in-all, they probably wrote 100 or so
RIDs, and not *ONE* of them said anything about your apparent
favorite issue, namely, that we aren't doing any on-orbit
testing with WP-4 hardware to verify the EVA procedures.

Also, just to note how important NASA considers the opinions
of the crew, a representative from the astronaut office had a
seat at the WP-04 Critical Design Review board.

Summary

On the one hand, I have the crew office providing detailed
RIDs listing their concerns regarding our EVA procedures, and
these RIDs contain no mention of a "problem" relative to
the lack of on-orbit tests to verify the EVA procedures. On
the other hand, I have Allen Sherzer venting his spleen on
how stupid NASA is since we don't see the obvious need for
these on-orbit tests.

The bottom line is, how credible are the water tank tests at
predicting the ability to perform the proposed SSF EVA tasks
on-orbit?

Allen's answer is that the tank tests are a lousy predictor
of the feasibility of successfully performing the EVA
procedure on-orbit.

The astronaut office, the group responsible for performing
the EVA tasks, says the tests are a credible predictor.

Unless Allen is a former astronaut with both water tank
and on-orbit EVA experience who
subsequently changed his name, I'll believe the astronaut
office.

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

Date: Wed, 24 Mar 1993 16:27:20 GMT
From: Frank Crary <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <1onsgi$[e-mail]> [e-mail] (Pat) writes:
>I saw some old Air FOrce/ NASA footage on the old skin suits.
>The fabric looked real hokey,  and the NASA PM for suit technology
>claimed it could only achieve 1.5 psi, and they needed 5,
>so it was a triple suit.
>Now with new spandex,  could a single layer produce between
>3-5 lbs counterpressure?

Almost certainly, but material strengths might not be the only reason
for using 1.5 psi layers: Putting the suit on was apparently a
problem. It required alot of strenght, pushing and pulling to get
into a suit stretched to 1.5 psi... Getting into a 5 psi one would
be much worse, and it's possible three, 1.5-psi layers would simply be
easier to get into. Three layers is also more damage resistant.
(By the way, the current inclination if for 8.5 psi suits, to avoid
pre-breath...)

By the way, the idea of using some sort of compressable foam layer
to equalize pressure (e.g. around joints) sounds promising: It
would certainly make for a clumsier suit, but perhaps not as
clumsy as one with pressurized joints.

                                          Frank Crary
                      CU Boulder

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

Date: Wed, 24 Mar 1993 18:01:40 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Why use AC at 20kHz for SSF Power?
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Pat) writes:

>In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>>In article <[e-mail]> [e-mail] (Richard A. Schumacher) writes:
>>
>>
>>   Oh, nuts. So a 20kHz power system saves 2,000 pounds, huh?
>>   Assume it costs $3,000 per pound to launch. Spend $6M on
>>   the extra weight of a 400 Hz system, and 20 minutes later
>>
>>If it were to become standard and used on other systems

>If the idea were so hot,  then it would be used on other areas.
>The only thing I see Utility power generation moving towards is
>Higher Voltage.  208/480 three phase is now getting pushed back
>by 5-7KV systems for campus distribution.

Utility power has always used HV lines for distribution.  Of course,
they also have to 'wheel' at each state border, too.  Yep, that's how
we should do it everywhere else, all right, cuz that's how it's always
been done.  Yup.

>>it would save a lot more weight in the long run.
>There were never plans to ever expand SSF beyonf the
>EMCC Eight Man Crew COnfig,  and  that was based upon
>very speculative budgeting.

>>When you're about to put up the first major piece
>>of infrastructure in space, one that might in principle be
>>expanded, it becomes sensible to consider the possibility of
>>whether a new standard for such things as power systems makes
>>sense in the long run.

>You mean, the way most things are built upon previous knowledge base?
>Gee stein, you seem real positive over this technology,
>why don't you go and build some lab equipment that pulls this
>as prime power.

>>One of the most frequent complaints here against NASA is that
>>they don't consider new technologies that might lower costs
>>in the long run and don't experiment with different concepts.

>Yet,  by the figures presented in the paper, which put
>only the most positive glow on 20KHz power, we seee only a
>6 Million weight savings and a claimed 150MIllion dollar lifecycle
>savings.  if we take the money saved on designing this idea, and put
>it in the bank, i bet we'd be looking at lifecycle savings of
>more then that.

Someone else already made the appropriate response to this one.  Gee,
we should have just banked what Columbus spent.

>>Yet, when they do and it doesn't work out they are chastised
>>(often by the same people) for wasting money when they could
>>have been using old and tried technology, and using the
>>magic of 20-20 hindsight it becomes "obvious" that the
>>new concept tried wouldn't work.

>If they had a solid disciplined engineering developement program
>to prove and test all this gear,Id believe it, to be worth
>exploring, but to go out on a tremendous technological limb
>on an untried technology on the most expensive NASA program this
>Decade, maybe even century,  is just plain rank foolishness.

The more you talk the less convinced I am that you know anything about
engineering, Pat.

>>
>>   As for the difficulty of shielding scientific instruments
>>   from 400 Hz noise: some EE better go tell those poor
>>   fool astronomers who have been flying their instruments
>>   in U-2s for 20 years that they're doing it all wrong...
>>   (Oh no! Now they're doing the same thing in an SR-71!
>>   Stop them before it's too late!)
>>
>>Those instruments are handbuilt at no small expense.

>No doubt, smaller then that for 20KHz.   Aren't most scientific
>devices hand built?  if it was production gear,  you'd get it at toys R us
>and lots of stuff is production built for 400KHz.  Radars,  computers,
>Motors, generators,  Power conditioners, Lights,  Fans,  Air conditioners,
>circuit breakers....

>None of that stuff is available for 20KHz.

>>
>>   20kHz power is a Boondoggle. A gold-plated, aerospace-
>>   contractor's-wetdream, engineering-porkbarrel boondoggle.
>>
>>Yeah right, NASA should just stick with old and tried concepts,
>>tie swans to balloons, or use large cannon and capsules lit
>>with gas lamps. And people wonder why NASA has become afraid
>>to take risks and run experimental missions...
>>

>Careful stein,  you are listening to nick and it's rubbing off.

>Actually my simple acid test on 20KHz, is why Boeing doesn't use it.

>If resonant inversion was such an efficient method,  and the weight
>savings were so high on motors, etc,  then 747's would be converted
>over to this standard,  or new boeing hardware would use this.

>Aircraft are very weight conscious, probably more so then Rockets.
>Airlines make money running packed to the gills,  running with 80%
>load, is a fast way to lose money.  some airlines need to carry 93%
>of cargo, to even break even on a route.  it depends on schedules
>and fares.

>I once read, that a 1 pound savings on a 747, translates to a 10,000
>dollar savings.  now this was when fuel was high, and god, that's
>a real dusty memeory,  but  It does seem illustrative.

>Commercial aviation is very weight conscious.  Military are even more,
>yet none of these guys have ever looked at this, to my knowledge,
>and boeing is very cash rich, and the AF spent 10 years with money
>as no object.

But not nearly as weight conscious as spacecraft have to be.  In
addition, needs are somewhat different between an aircraft and a space
station.  Personally, I think 20kHz was a bad idea, but I also think
that this insistence of yours that if it was good enough for the
Wright brothers it's good enough for SSF is just a bit silly.

--
"Insisting on perfect safety is for people who don't have the balls to live

 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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End of Space Digest Volume 16 : Issue 365
------------------------------