Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V09_5/V9_544.TXT

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Date: Thu, 20 Jul 89 05:17:53 -0400 (EDT)
Subject: SPACE Digest V9 #544

SPACE Digest                                      Volume 9 : Issue 544

Today's Topics:
              Re: Don't mess with NASA?
            Re: Space station experiments
              Re: Don't mess with NASA?
           Procurement and future computers
            Spin Angular Momentum
           Re: Don't mess with NASA (afterburners)
           Re: Don't mess with NASA (afterburners)
         Re: Procurement and future computers
           Re: Don't mess with NASA (afterburners)
Re: Harris Corp. selected for Advanced Communications Technology work (Forwarded)
----------------------------------------------------------------------

Date: 5 Jul 89 15:34:04 GMT
From: skipper![e-mail]
Subject: Re: Don't mess with NASA?

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>In article <[e-mail]> [e-mail] writes:
>>>Actually, you can find non-government birds with afterburners, but there
>>>aren't very many of them and often they aren't very accessible.
>>
>> [F-20] ...What others are there?

>I know of two others which used to exist:  Darryl Greenamyer's souped-up
>Starfighter and the privately-owned T-38 in California.  Greenamyer's
>Starfighter, alas, is junk following a gear-deployment failure after a
>world-low-altitude-speed-record flight, and I seem to recall hearing that
>the California T-38 got written off recently too.  Rats.

Henry, those two aircraft were specified and funded by the U S
government, regardless of their final owners.  No free enterprise
there.  The F-20 (a nearly-perfect airplane) was funded solely by
Northrop--no government involvement at all.  Lockheed was paid to
build the F-104 and Northrop was paid to build the T-38.  (About that
T-38 accident--one of our pilots said it was too much airplane, too
little pilot :-))

>>That's what this country needs--general aviation with afterburners!
>>I'm ready!

>Me too!  Unfortunately the US military wants to keep jet aviation all to
>itself, so even its tamer aircraft are never sold to civilians.  (Both
>the Starfighter and the T-38 were rebuilt from hardware that slipped out
>basically by accident.)

Like the BD-5J?  USAF even bought/leased a couple of these to test,
wondering if they were suitable for military use.  Turned out they had
terrible flying qualities (I know one of the pilots who fley it and he
has a lot to say about the pitch stability!).  It didn't have an
afterburner, either.  The company went out of business because there
wasn't a big enough market at the price they had to charge.

If you can design, build, and sell a general-aviation jet aircraft
with or without an afterburner, do it.  Jim Bede did.  The military
doesn't care.  Just don't arm it--that makes them testy.

Greenamyer's F-104 was the structural test article--I'm not sure I'd
like to fly in something used to test structural fatigue life!
There's another TF-104, in a museum in Texas that also has a MiG-15
and an F-86.  One of our test pilots flies all three for them.
There's also at least one single-seat F-5 around.
--

M F Shafer                          [e-mail]
NASA Ames Research Center           arpa!elxsi.dfrf.nasa.gov!shafer
Dryden Flight Research Facility     ames!elxsi!shafer
Of course I don't speak for NASA    DON'T use the drynix address

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

Date: Wed, 5 Jul 89 17:41:32 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Space station experiments


>From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
>NASA SELECTS SCIENCE EXPERIMENTS FOR SPACE STATION FREEDOM
...
>     The following individuals have been selected for funding for
>experiments and concept studies in response to the January 1988
>announcement:

>Dr. Glenn C. Carle, Ames Research Center, Moffett Field, Calif.  <<<<<<
>Exobiology Intact Capture Experiment, flight experiment.         <<<<<<

Anybody have more information on that experiment? Sounds interesting!
                             John Roberts
                             [e-mail]

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

Date: 5 Jul 89 15:16:59 GMT
From: skipper![e-mail]
Subject: Re: Don't mess with NASA?

In article <[e-mail]> [e-mail] (Peter Kendell) writes:

>Path: skipper!ames!lll-winken!uunet!mcvax!ukc!stl!stc!pete
>From: [e-mail] (Peter Kendell)
>Newsgroups: sci.space
>Date: 4 Jul 89 15:01:15 GMT
>References: <[e-mail]>
>Organization: STC Telecoms, London N11 1HB.
>Lines: 18

>From article <[e-mail]>, by [e-mail] (Henry Spencer):
>}
>} Actually, you can find non-government birds with afterburners, but there
>} aren't very many of them and often they aren't very accessible.

>>>  What about Concorde? Just the price of a British Airways or
>>>  (perhaps preferably) Air France ticket.

You missed a little of the joke.  I was "chiding" Henry for wanting to
ride in a "real" airplane with afterburners when he is such a strong
proponent of free enterprise and the stamping out of government
funding and interference.  Concorde was a government project the whole
way so it would fail that particular test, as do virtually all
fighters (except the F-20).

Concorde is an exceptionally nice airplane to fly in and Air France
feeds you marvelously for the entire trip.  I was eating truffled
lobster and sipping champagne when we went through Mach 2.  That
really felt decadent!

--

M F Shafer                          [e-mail]
NASA Ames Research Center           arpa!elxsi.dfrf.nasa.gov!shafer
Dryden Flight Research Facility     ames!elxsi!shafer
Of course I don't speak for NASA    DON'T use the drynix address

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

Date: Wed, 5 Jul 89 17:07:02 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Procurement and future computers


>From: [e-mail]
>> There is a set of articles in the June 1 issue of Computer Design describing
>> changes in military procurement of mil-spec and off-the-shelf equipment and
>> relevant issues, plus the evolution and current status of Ada.
>If true, maybe we'll see the end of the era of the $100 hammer ($15 for
>a good 20 oz hammer, $85 for the paper)
(In the article, it was a $700 hammer, with most of the cost in *testing* and
paperwork.) There will always be "mission-critical" situations, especially in
space, for which the $700 hammer is definitely worthwhile. The key is to
identify those situations in which such high reliability is not necessary.
One of the changes is the addition of several grades between OTS ("off the
shelf") and full mil-spec. You might, for instance, have a $50 hammer. (I've
broken enough hammers to see a need for at least some quality control for a
hammer to be used where it's hard to get a replacement.) Procurement is also
being changed so it is the more expensive grades that must be justified
rather than the cheaper ones.

------------------------------
>If you want a sophisticated machine for 1998, and you REALLY MUST roll
>your own, then do something real instead of spending many millions for
>a museum piece. I'd suggest you look at:

>    - minimum resolution on screen of 300 dpi (400 would be nicer)
>      with ~32 bits per pixel to handle color, intensity and
>      transparency.
How would you allocate the bit fields? Many display designers regard 24 bits
(8 each of RGB) as being fully satisfactory for both color and intensity.
Does "transparency" in this context mean priority of overlapping objects or
frames?

>    - full spoken language translation capability between all
>      langauges of space faring nations. (ie build on the work the
>      japanese have already done. If IBM can't handle it, buy the
>      consumer market translators that will be coming out of Nippon
>      in a couple years.)
Automatic full language translation and continuous speech recognition have
been "a couple of years away" for ~3 decades now. During this time, new
problems have appeared about as fast as the technology has progressed. At the
New York World's Fair, there was a translation machine with teletypes on which
you could enter text, and it would come out in a different language. (The
humans who did the actual translation were hidden away somewhere.) A few years
ago, IBM ran commercials in which a person dictated "Please write Mrs. Wright
right now", and it came out perfectly - must have been authentic, because you
could see it right on television! :-) Even when the basic capability is
developed, real-time performance will still be a problem: modern supercomputers
can take on the order of half an hour to analyze a few seconds of speech, and
I don't think the problem lends itself very well to massive parallelism, the
main hope for higher computational speed in the short term. I suspect the best
chance is the development of specialized hardware that does the sort of
preprocessing performed by the "automatic" portions of the human brain. In the
meantime, voice synthesis and recognition of discrete words from a limited
vocabulary are orders of magnitude simpler, and are available now to some
extent.

------------------------------
>120 dpi is not acceptable for archival purposes. 400dpi is probably
>marginal. Would you want the Mona Lisa archived for historians at only
>120dpi? I wouldn't even store my personal archives at that low a dpi.
>And even if you store high and downsample on display, then you still
>have to do hardcopy everytime you want to study color pictorial
Digitization, storage, and display/printout are more or less separate problems,
except that more pixels digitized means more storage required, and more pixels
on a scanning display means faster display memory needed. I wouldn't mind
having a 120dpi display 10 feet across :-)

>I would not want to store and display photographic material
>at a resolution less than the grain size of the film.
Do you have any good numbers for a 35-mm negative, i.e. Kodak Gold 100, on
its equivalent in pixels and bits per pixel? I don't, but I would guess
~1000-3000 pixels across. How about an IMAX image?

>>    I'd be surprised to see 64MB PC's this year, especially for
>NeXT is only waiting for the quantities to be available. The NeXT
>machine as it exists TODAY can handle this. It has simply not been
>tested with the new chips.
>>    Hey, what's a factor of 2000 between friends?  You may have
>Yeah, you are probably right. Probably won't be more than 128GB by
>1998...
Be careful about factors of 2000. Designers are beginning to approach the
fundamental limits on what can be built and made to work reliably using
extrapolations of current techniques. Precision of line placement, insulation,
and power dissipation become harder to handle as machines speed up and
linewidths shrink. The transition from 256kb DRAMS to 1M and 4M is being
accomplished partly be making the actual chips bigger. There is a limit to
how much memory can be fitted into a computer and still have it considered
inexpensive enough to be a "personal" computer. There is a good chance that
innovative approaches (i.e. solid-state optical storage) will eventually
get us past the current "barrier", but it's not practical yet to predict
when this might happen.
                           John Roberts
                           [e-mail]

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

Date: 5 Jul 89 21:37:10 GMT
From: frooz![e-mail]  (Steve Willner)
Subject: Spin Angular Momentum

Material originating in sci.space:

From article <Added.IYfxRrG00Ui38Gzk9=@andrew.cmu.edu>, by [e-mail]:
>>2) Regarding elementary particles -- one of their characteristics is called
>>"spin". Is this REALLY "spin" the way a top or gyroscope spins...?

> Here there was some misinformation.  Spin is NOT angular momentum!!
> Rather, it is a purely quantum mechanical phenomenum (like the quantites
> of colour you mention above).  People mistakenly think that it is an
> angular momentum because of its mathematical properties.

I'm not sure what you mean, but if the spin direction of one particle
in a quantum mechanical system changes, the angular momentum of some
other part of the system must also change.  Total angular momentum,
including the vector sum of all spins, is conserved.  (And you mustn't
forget to include photons, which have spin 1).  To me, this seems
equivalent to saying that atomic spin is one form of angular momentum.
Certainly it is common to speak or write about "spin angular momentum."
Did you just mean to say that one's mental picture should be different
than a gyroscope?

An example is the spontaneous radiative decay of a hydrogen atom from
high principle quantum number (n).  Allowed decays have change in
orbital angular momentum (l) of +/- 1, precisely because the photon
spin carries one unit of angular momentum.  Changes by +/- 2, 3, etc.
are forbidden.  (Or rather, they are allowed only for multi-photon
processes, which are generally of negligible probability except for
special cases like the hydrogen 2s configuration, from which all
single-photon decays are forbidden.  In the two-photon decay, the
photons have opposite spins, allowing the net change in the atomic
angular momentum to be zero.)  Multi-electron atoms have other
selection rules, but total angular momentum (j) is always conserved.

Followups should probably go to sci.physics or be conducted by e-mail.

Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

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

Date: 5 Jul 89 15:08:11 GMT
From: skipper![e-mail]
Subject: Re: Don't mess with NASA (afterburners)

In article <[e-mail]> [e-mail] (Ian Macey) writes:

>Nope, Concorde doesn't use afterburners. But then again it doesn't need to
>to leave most fighters standing.

It certainly does.  It takes off in 'burner and then goes back into
'burner while accelerating through the transsonic region.  I know, I
was there.  (Reheat is the British term for afterburner--maybe this
led you astray?.)

Attractive though it may be, Concorde won't leave any modern western
fighters standing.  Top speed may be greater than some fighters, but
they'll beat it `off the line'.  (Do you have drag racing in the U K?)
--

M F Shafer                          [e-mail]
NASA Ames Research Center           arpa!elxsi.dfrf.nasa.gov!shafer
Dryden Flight Research Facility     ames!elxsi!shafer
Of course I don't speak for NASA    DON'T use the drynix address

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

Date: 6 Jul 89 06:33:36 GMT
From: [e-mail]  (Jonathan Patrick Leech)
Subject: Re: Don't mess with NASA (afterburners)

In article <[e-mail]> [e-mail] (RAMontante) writes:
>Does this disqualify it as a `B-2' bomber?  I can't see too many big
>planes standing on their tails at the end of the runway, even without a
>bomb load...

    Hm, guess you didn't see the C-130 RATO assisted takeoff at the
Moffett airshow last weekend...  not quite on its tail, but amazing
nonetheless.
    Followups to rec.aviation.
--
    Jon Leech ([e-mail])
    Apple Integrated Systems
    __@/

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

Date: 6 Jul 89 16:54:26 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Procurement and future computers

In article <[e-mail]> [e-mail] (John Roberts) writes:
>>      with ~32 bits per pixel to handle color, intensity and
>>      transparency.
>How would you allocate the bit fields? Many display designers regard 24 bits
>(8 each of RGB) as being fully satisfactory for both color and intensity.

Those designers obviously have never talked to remote-sensing people,
who do *not* consider 8 bits per color really adequate.  Said folks would
really prefer 10 or 12 (although of course they have to take what they
can get...).  And this is a lot more relevant to the space station than
arguments about how many thousands of dots per inch you need to reproduce
fine art well enough to satisfy museum experts...
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: 6 Jul 89 16:50:33 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Don't mess with NASA (afterburners)

In article <[e-mail]> [e-mail] (Ian Macey) writes:
>Nope, Concorde doesn't use afterburners...

Nope, it does use afterburners, throughout its flight.  They had originally
hoped that afterburners wouldn't be needed during cruise, but it didn't turn
out that way.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: 6 Jul 89 20:31:36 GMT
From: [e-mail]  (Jonathan Patrick Leech)
Subject: Re: Harris Corp. selected for Advanced Communications Technology work (Forwarded)

In article <[e-mail]> [e-mail] (Peter E. Yee) writes:
>RELEASE:  89-109
>...
>     ACTS is a key element in NASA's efforts to develop high-
>risk, advanced communications technology usable in the higher
>frequency bands to support our nation's future communications
>needs.  Realization of this goal will enable the U.S. to maintain
>preeminence in satellite communications.

    Oh really? I guess that explains why NASA kept removing ACTS from
their budget request, and Congress kept putting it back.
--
    Jon Leech ([e-mail])
    Apple Integrated Systems
    __@/

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

End of SPACE Digest V9 #544
*******************