Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V09_5/V9_543.ZIP/V9_543

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Date: Thu, 20 Jul 89 03:17:42 -0400 (EDT)
Subject: SPACE Digest V9 #543

SPACE Digest                                      Volume 9 : Issue 543

Today's Topics:
              Re: Don't mess with NASA?
    Re: space news from May 15 AW&ST (replacing computers)
              Re: Don't mess with NASA?
              Re: Don't mess with NASA?
           Re: HR2674: Dear Space Activist
              Re: Two Questions
                  Re: Apollo
           Re: Don't mess with NASA (afterburners)
             Re: Space station computers
               Re: SPACE Digest V9 #535
           Re: Don't mess with NASA (afterburners)
           Voyager Status for 07/05/89 (Forwarded)
           Space program on PBS-TV in July.
----------------------------------------------------------------------

Date: 4 Jul 89 15:01:15 GMT
From: mcvax!ukc!stl!stc![e-mail]  (Peter Kendell)
Subject: Re: Don't mess with NASA?

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.

} $10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
} (Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]
     ^^^^^^^^^^^^^
     Please explain!

--
----------------------------------------------------------------------------
|          Peter Kendell <[e-mail]>                   |
|                ...{uunet!}mcvax!ukc!stc!pete           |
----------------------------------------------------------------------------

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

Date: 4 Jul 89 15:43:06 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: space news from May 15 AW&ST (replacing computers)

In article <[e-mail]> [e-mail] (Steven M. Bellovin) writes:
>> The real botch here is that the computers are so inaccessible that it takes
>> four hours to replace one.
>
>Sorry, I don't necessarily agree.  As Henry obviously knows, design of
>something like a space shuttle is a series of tradeoffs...

Granted... but NASA has somewhat of a history of assuming that the hardware
must work -- it says so in The Book, after all! -- and so it's unnecessary
to set things up so the astronauts can fix it.  I.e., while tradeoffs do
happen, they can and do get skewed by institutional biases.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: 4 Jul 89 06:53:08 GMT
From: alpha![e-mail]  (Billy Harvey)
Subject: Re: Don't mess with NASA?

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] writes:
> >>... If you want class when climbing into an aircraft, it has to have
> >>afterburners.
> >
> >Better watch it, Henry--you'd have to do it in a government-sponsored,
> >government-funded aircraft!  :-) :-)
>
> Ouch.  Touche. :-)

Theres a saying military pilots have - "Just remember, what you're flying
was built by the lowest bidder!"













Billy Harvey            [e-mail]

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

Date: 4 Jul 89 20:08:51 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Don't mess with NASA?

In article <[e-mail]> I wrote:
>>>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...

And of course, I forgot about Concorde.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: 4 Jul 89 16:08:01 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: HR2674: Dear Space Activist

In article <[e-mail]> [e-mail] (William Baxter) writes:
>Here is Ron Packard's letter to Space Activists.  Are you one?  This
>bill needs more Cosponsors.  Have you seen your Representative about
>HR2674?

I too would urge US readers to get off their behinds and ask their
Congressthing whether he/she/it supports this, and if not why not.  This
bill looks like a very good thing.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: Wed, 5 Jul 89 01:12:04 -0500
From: [e-mail] (Andrew V. Royappa)


Please remove me from this list.

            Thanks,

                Andrew Royappa

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

Date: 5 Jul 89 04:20:40 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Two Questions

In article <[e-mail]> [e-mail] (Greg Goebel) writes:
>   1: A recent AEROSPACE AMERICA article discussed nuclear propulsion
>      and kept referring to "specific impulse", measured in seconds?
>      Can anyone please define?

It's a peculiar and somewhat archaic but still widespread way of measuring
exhaust velocity.  It's thrust*time/fuelweight, and the units happen to be
seconds because of the peculiar notion of measuring fuel burn by weight
rather than mass.  It turns out to be exhaustvelocity/g, where g is the
acceleration of gravity, 9.81 m/s^2.  Exhaust velocity is the fundamental
measure of rocket engine performance; via conservation of momentum, it
determines how much boost you get out of each kg of fuel.

(Okay, for the curious...  For a pure rocket, carrying its fuel with it,
integration of the differential equation of momentum conservation gives
us
    velocitychange = exhaustvelocity * ln(massbefore/massafter)

as the basic rocket equation.  Note the natural logarithm; what this says
is that it's very hard to get velocity changes more than a few times the
exhaust velocity.  Hence the importance of high exhaust velocity.)

>   2: Mr. Spencer (being the usual gold mine of information that he is)
>      made reference to Giotto being reactivated.  What is the current
>      operational capability of Giotto?  I thought it had been damaged
>      somewhat by the Halley flyby (but "Ah could be wrong!")

Giotto is thought to be somewhat damaged, but also thought to be working
well enough for another comet encounter to be useful.  We won't know for
sure until the revival attempt is made and tests are run.  Last I heard,
the external mirror assembly for the camera is thought to be completely
gone [!], which probably means no pictures.  But most of the other science
instruments should still be okay.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: Wed, 5 Jul 1989 12:35-EDT
From: [e-mail]
Subject: Re: Apollo

> follow-ons.  (Anyone who claims that Apollo was always meant to be a
> one-shot has never seen some of the work Apollo did on follow-ons to the
> early missions.  Apollo was strangled in infancy.)

Again, Henry...  I agree that the engineers had lots of pretty pictures
and pipe dreams of what wondrous things they were going to do after
Apollo. BUT... I do not believe that the politicians EVER had any such
ideas. Apollo was politically motivated, had a clearly defined goal,
and was disassembled as soon as the goal was reached and sucked dry of
political profit. That was inherent in the project from it's inception.

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

Date: 6 Jul 89 02:28:47 GMT
From: [e-mail]  (RAMontante)
Subject: Re: Don't mess with NASA (afterburners)

[e-mail] <[e-mail]> :
-
-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?)

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...

Sure, let's drop truffles and champagne on the Warsaw Pact forces.  That
should *really* demoralize 'em!

[In a desperate attempt to get relevant again...] I *personally* think
that a "classy ride" is one that can't use aerodynamic control surfaces.

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

Date: Wed, 5 Jul 1989 12:17-EDT
From: [e-mail]
Subject: Re: Space station computers

> There are reasons, quite apart from technical feasibility, why touch
> screens and voice input have never been terribly popular except for
> specialized applications.

Ah, Henry. I think we are in disagreement on this one. I've spent the
last 4 years doing gesture research and I really think you are wrong.
But this is not the place to go into the details of the technology I am
discussing. It is NOT a touch screen. Some of the work was supported by
NASA SBIR's to a local company subcontracted to the CMU Computer Music
Lab. I think one of the reason's is that there is interest in non-mouse
techniques of direct manipulation that do not require getting dressed
(gloved, visored) for the computer. Fingers do not require gravity for
operation.

I could go into many other reasons for the advantages of direct
manipulation. Using a mouse is like having 9 out of 10 fingers cut off.

And on the issue of resolution, I will hold my ground. I have discussed
the issue with an archivists and find agreement. I have heard of even
MORE severe requirements for the arts, particular the storage of
etchings with very fine line width modulation. The feel of the art
CANNOT be conveyed without DPI resolutions far, far in excess of any I have
suggested. Yes, you can zoom in on areas. But you lose the essence of
the whole picture.

Show me an art work original, and show me the piece at 120 DPI and
guarantee you I will see an overwhelming difference.

And if 400 DPI were enough, then typesetters wouldn't bother with the
expensive equipment for printing books. They'd just use your
laserwriter output.

120 DPI might seem miraculous to a long time computer user. But
archivists, artists, and people used to "analog" media are not
impressed by it.

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

Date: Wed, 5 Jul 1989 12:46-EDT
From: [e-mail]
Subject: Re: SPACE Digest V9 #535

> I also believe that Ada was originally conceived as a  high-water  mark  in
> DSD  and  DASD  design, and the OOD support comes, as for OOD itself, as an
> evolution from these techniques.

Object Oriented Design comes from Smalltalk, not NASA or DOD. Let's
keep our spinoff claims honest...

> Of course, I'm somewhat biased, as I was converted from  PL/M  to  Ada  for
> system implementation purposes, and the system that I'm doing Ada on
> has OS

NO WONDER YOU LIKE ADA. I wrote about 20K lines or so of PL/I about 15
years ago. It is the most GAWDAWFUL language I ever had the misfortune to
deal with. (The most telling statement in one of the IBM manuals was
a place that made the statement, "In this case PL/I will probably...")

Personally I'd rather use Objective-C or an object oriented LISP with
the ability to link in routines written in other languages. I've done a
fair amount of NASA SBIR work using such techniques. I would NOT
encourage any company I was involved in to go for on board station
software though, because I find ADA to be of little use in the real
market place.

I would state again, that in my opinion, ADA is not an object oriented
language. It is a very large complex language that has enough different
sets of features that one can FAKE many of the techniques of object
oriented programming. It does not, to my knowledge, have Classes,
Class inheritance (single OR multiple), Class and Object Methods.

I'd love to see a sample of the ADA standard syntax for sending a
message to an object to execute a method on an argument list of
optional length...

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

Date: 5 Jul 89 10:27:49 GMT
From: mcvax!ukc!stl!stc!praxis!hilbert![e-mail]  (Ian Macey)
Subject: Re: Don't mess with NASA (afterburners)

In article <[e-mail]> [e-mail] (P. Kendell) writes:
>From  <[e-mail]>, by [e-mail] (H. 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

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

Hey! How about putting a bomb bay in a Concorde and calling it a B2? (could
have saved the US government millions!!! :-)

Ian.

|\\\X\\|\  |           Ian Macey  Bath, England.  ([e-mail])
|\\X\\\|\\ |   ----------------------------------------------------------------
|\X\\\\|\\\|       " there are never no bugs, only bugs you haven't found "

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

Date: 6 Jul 89 00:42:13 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Voyager Status for 07/05/89 (Forwarded)

Voyager Status Report
                        July 5, 1989


     Voyager 2's television cameras this week remained the
only experiment on the spacecraft to detect Neptune, a fact
that does not surprise Voyager scientists who anticipate that
many of the experiments will not "see" the Neptunian system
until a month or even days before the spacecraft's closest
approach.

     The planetary radio astronomy (PRA) experiment, which
detects radio-wave emissions from planets, has not yet
"heard" Neptune.  But interestingly, the instrument is still
hearing radio emissions from Jupiter which, next to the Sun,
is the noisiest radio source in the solar system.

     This Friday, the heating unit for the 20-inch mirror in
the infrared interferometer and spectrometer (IRIS) will be
turned off to allow the heat-mapping instrument to cool down
to its approximately 0 degree Celsius (32 degree Fahrenheit)
operating temperature.  When the IRIS is not making
observations, the heater is kept on to preserve the
instrument's sensitivity.  A 1 1/2-month cool-down period
will ensure the IRIS is ready for its most critical
observations of heat emissions from Neptune and Triton
beginning about 10 days prior to Voyager 2's closest approach
to the planet.



DISTANCE FROM EARTH:  2,670,438,000 miles
DISTANCE FROM NEPTUNE:  45,495,000 miles
HELIOCENTRIC VELOCITY:  42,202 mph

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

Date: 5 Jul 89 19:30:00 GMT
From: wrksys.dec.com![e-mail]  (CUP/ASG, MLO5-2/G1 6A, 223-3283)
Subject: Space program on PBS-TV in July.


        There will be a two-part program on Public Broadcasting Service
    (PBS-TV) this month, titled "The Other Space Race".  The first part
    (July 16) examines the space technology of China and Japan,
    concentrating on communications, weather, and remote-sensing
    technology.  The second part (July 23) examines space programs
    underway in Europe.  You will have to check your local listings
    for times.  These programs are part of a series called INNOVATION.
    Source:  SCIENCE NEWS, June 24, 1989.

        Larry Klaes  [e-mail]
             or - ...!decwrl!renoir.dec.com!klaes
                 or - [e-mail]

             N = R*fgfpneflfifaL

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

End of SPACE Digest V9 #543
*******************