Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V09_5/V9_536.TXT

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Subject: SPACE Digest V9 #536

SPACE Digest                                      Volume 9 : Issue 536

Today's Topics:
               Atari(s) and Sat Photos
              Re: Don't mess with NASA?
              Re^2: Fuel for lunar trip
    Re: space news from May 15 AW&ST (replacing computers)
       Re-play of Apollo 11 TV Coverage and 20th Anniv. at NASM
       Re: Space Deaths (was Re: Killing Borgs easily)
           Re: Re: Space station computers
           Re: Re: Space station computers
              Re: Don't mess with NASA?
                NOAA-9
----------------------------------------------------------------------

Date: 30 Jun 89 05:33:53 GMT
From: sun-barr!texsun!convex!iex!ntvax![e-mail]  (cqyang class)
Subject: Atari(s) and Sat Photos

>Article 3587 of sci.space:
>In article <[e-mail]> [e-mail] (Frank Rahmani) writes:
>>There was a posting very recently on the net (schematics and software)
>>that used an average Atari computer to receive satpics.
>Please, folks, if you post something like this, give a more specific reference
>than "on the net".
> Spencer at U of Toronto Zoology

   I did not see that particular posting, and I hope I am not repeating what
may have already been sent, but the September 1986 issue of 'Antic the Atari
resource' magazine has some articles on receiving weather satellite pictures
(WEFAX pictures) for both an Atari 800 and an Atari ST. Also 1987 and 1988
issues of 'QST' magazine have some articles on receiving weather satellite
pictures for different types of computers.

******************************************************************************
*                           *                                                *
*  Jim Stinson              *     This space intentionally left blank        *
*                           *           (sort of)                            *
* [e-mail]   *                                                *
*                           *                                                *
******************************************************************************

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

Date: 30 Jun 89 16:43:40 GMT
From: b.gp.cs.cmu.edu![e-mail]
Subject: Re: Don't mess with NASA?

In article <[e-mail]>, [e-mail] (Bob Myers) writes:
}>period.  If you want class when climbing into an aircraft, it has to have
}>afterburners.
}BIG "afterburners".  Say, something along the lines of five F-1 engines...:-)

Eight* would have been much nicer.  No fooling around with LEO, LLO, or LLO
rendevous.  Just light them here and fire the retros for a soft landing at
the destination, without all the trouble of docking, three different orbits,
etc.

*The original "Nova" booster concept with 12 million pounds of thrust.
--
UUCP: {ucbvax,harvard}!cs.cmu.edu!ralf -=-=-=- Voice: [phone] (school)
ARPA: [e-mail]  BIT: ralf%cs.cmu.edu@CMUCCVMA  FIDO: Ralf Brown 1:129/46
            Disclaimer? I claimed something?
"When things start going your way, it's usually because you stopped going the
 wrong way down a one-way street."

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

Date: 1 Jul 89 03:06:26 GMT
From: zephyr!tektronix!psueea!parsely!bucket![e-mail]  (Leonard Erickson)
Subject: Re^2: Fuel for lunar trip

[e-mail] (Peter Scott) writes:

>mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer) writes:

>>At one point there was a proposal to take up water ballast on shuttle missions
>>that were volume-limited rather than weight-limited, and offload the ballast
>>at an orbiting facility that would electrolyze it and liquefy the resulting
>>hydrogen and oxygen.

>Water takes up volume too.  Where were they proposing to store it?  Does the
>shuttle fly with water tanks that are partially empty on weight-limited
>missions?

Water takes up less volume than an equivalent mass of hydrogen and oxygen,
even LOX and LH2. It's a matter of *density*. LH2 is not very dense at all,
and LOX isn't a lot better. Water is a very space efficient way of storing
them.

--
Leonard Erickson        ...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short

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

Date: 2 Jul 89 21:09:44 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] (Roy Smith) writes:
>> the Atlantis crew replaced one of the orbiter's five general-purpose
>> computers after it failed ...
>
>    I don't understand.  I thought that the various computers were all
>constantly checking each other and if one failed, it would be taken off line
>automatically and the others would continue to operate without it.  Why the
>need to rummage around behind the furniture for 4 hours?

Almost certainly they could have completed the mission without doing so.
However, having one computer dead *before* reentry means having that much
less redundancy available against the possibility of further failures.
So shuttle mission rules say that if time and parts are available, the
repair will be done.  If you were aboard, would *you* vote for reentering
with one computer dead if you could avoid it?

The real botch here is that the computers are so inaccessible that it takes
four hours to replace one.
--
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry [e-mail]

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

Date: Sun, 2 Jul 89 14:44:39 EDT
From: [e-mail]
Subject: Re-play of Apollo 11 TV Coverage and 20th Anniv. at NASM

A while back I believe someone posted some information about a cable
channel (?Discovery? A&E?) planning to re-broadcast coverage of the
Apollo 11 flight during the 20th anniversary; I had the impression they
were going to cover a lot of the mission running it at the same time and
date as the original.  Was this wishful thinking on my part?  If someone
would let me know if this is indeed scheduled, I'd appreciate it.  Thanks.

For those who live in the DC area, the National Air and Space Museum has
two events planned.  On Monday, 17 July at 20:00 they are showing "We
Came In Peace For All Mankind", a film about the Apollo program.  On
Thursday 20 July they are hosting a "Lunar Landing Party" from 19:30 ..
01:30, including re-plays of some of the TV coverage.

Happy Anniversary,

    Chuck Howell
    MITRE, Mail Stop Z-645
    7525 Colshire Drive
    McLean, VA 22102-3481
    [e-mail]

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

Date: 2 Jul 89 18:27:19 GMT
From: m2c!wpi![e-mail]  (Tom [Chris] Murphy)
Subject: Re: Space Deaths (was Re: Killing Borgs easily)

In article <[e-mail]> [e-mail] (Christopher K Davis) writes:
>
>USSR: 3 deaths on Soyuz 1, 3 on Soyuz 11, others "suspected."
>
>So at least 16.


Soyuz 1 had only one crew mamber, so the total is 14.

Tom Murphy
[e-mail]

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

Date: 30 Jun 89 18:33:22 GMT
From: hpfcdc!hpfcdj![e-mail]  (Bob Myers)
Subject: Re: Re: Space station computers

>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)

Well, speaking as a person who has spent the last few years mucking around
with monitors and the like, let me say that the technical phrase associated
with the above statement is "not a chance in hell", at least if you're
talking about a color display.  (Yes, a 300 dpi monochrome display exists
today - but much of what I'm about to say applies here as well.)

First off, the timing is frightening.  The one thing we know we want in
future displays is reduced flicker, which means increasing the vertical
refresh rate.  72 Hz would be a nice number, which, when coupled with the
dot resolution required for 300 dpi on a reasonable size display - say,
4k x 3k on a 19" screen - puts the dot clock comfortably over 1 GHz, and
horizontal sweep speed at 250 kHz or so.  Not bloody likely.  ("AHA!", you
say.  "He's talking about *CRT* displays!!! What about LCDs or other flat-panel
technologies.  Persons asking such questions are invited to study LCD
manufacturing technology, and then return with a paper covering defect
densities, etc..  There will be a short quiz later.)

The next problem, in a color display, is the need for a shadow mask (or
aperture grille, if you're a Sony aficionado) and phosphor dots/stripes of
appropriate size.  Present tube sizes/resolutions require, for around 100 dpi,
a "dot pitch" of about 0.3 mm - meaning that each group of three phosphor dots
is about 0.3 mm across (actually, the "pitch" is the distance from, say, the
red dot of one group to the red dot of the adjacent group).  Now, go figure
what this has to be for a 300 dpi display.  We'll likely see CRT displays in
the 2k x 1.5k range come into popularity over the next few years, but these
will only be about 150 dpi or so - and it's a BIG jump to 300 dpi tubes.

It will be far better, and easier in the long run, to use additional memory
so that techniques such as anti-aliasing, etc., can be applied to lower-than-
300 dpi systems.  Sure, we'll get to higher resolutions someday - but not by
1998.


Bob Myers            | "Writing is not necessarily something to be ashamed of -
myers%hpfcla@hplabs. |  but do it in private, and wash your hands afterwards."
hp.com               |                   - Lazarus Long/Robert A. Heinlein
----------

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

Date: 30 Jun 89 18:32:14 GMT
From: hpfcdc!hpfcdj![e-mail]  (Bob Myers)
Subject: Re: Re: Space station computers

>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)

Well, speaking as a person who has spent the last few years mucking around
with monitors and the like, let me say that the technical phrase associated
with the above statement is "not a chance in hell", at least if you're
talking about a color display.  (Yes, a 300 dpi monochrome display exists
today - but much of what I'm about to say applies here as well.)

First off, the timing is frightening.  The one thing we know we want in
future displays is reduced flicker, which means increasing the vertical
refresh rate.  72 Hz would be a nice number, which, when coupled with the
dot resolution required for 300 dpi on a reasonable size display - say,
4k x 3k on a 19" screen - puts the dot clock comfortably over 1 GHz, and
horizontal sweep speed at 250 kHz or so.  Not bloody likely.  ("AHA!", you
say.  "He's talking about *CRT* displays!!! What about LCDs or other flat-panel
technologies.  Persons asking such questions are invited to study LCD
manufacturing technology, and then return with a paper covering defect
densities, etc..  There will be a short quiz later.)

The next problem, in a color display, is the need for a shadow mask (or
aperture grille, if you're a Sony aficionado) and phosphor dots/stripes of
appropriate size.  Present tube sizes/resolutions require, for around 100 dpi,
a "dot pitch" of about 0.3 mm - meaning that each group of three phosphor dots
is about 0.3 mm across (actually, the "pitch" is the distance from, say, the
red dot of one group to the red dot of the adjacent group).  Now, go figure
what this has to be for a 300 dpi display.  We'll likely see CRT displays in
the 2k x 1.5k range come into popularity over the next few years, but these
will only be about 150 dpi or so - and it's a BIG jump to 300 dpi tubes.

It will be far better, and easier in the long run, to use additional memory
so that techniques such as anti-aliasing, etc., can be applied to lower-than-
300 dpi systems.


Bob Myers            | "Writing is not necessarily something to be ashamed of -
myers%hpfcla@hplabs. |  but do it in private, and wash your hands afterwards."
hp.com               |                   - Lazarus Long/Robert A. Heinlein

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

Date: 2 Jul 89 17:22:22 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] (Jonathan Patrick Leech) writes:
>>>EMBARASSING!! EMBARASSING!!!  There is such class to crawling into
>>>a DC-3 at an airport that there is not even any word for such mega-
>>>class.  The only thing better than a DC-3 is TWO DC-3s.
>>
>> Are you sure you're not really Henry "Version 7" Spencer posting
>>under an alias?

>He definitely isn't.  I consider the DC-3 a charming historical relic,
>period.  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!  :-) :-)

--

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: 2 Jul 89 13:57:13 GMT
From: cs.utexas.edu!ut-emx![e-mail]  (Frank Abernathy)
Subject: NOAA-9

I've noticed that NOAA-9 does not seem to be alive on 137.620mhz
for APT services any more.

Has not been transmitting for about a week on the primary 137.62
or secondary 137.5 frequencies.

Anyone know if this satellite is lost to APT service?
HRPT might still be in service, but I don't have the 1698 or 1707Mhz
stuff to receive it.

Thanks in advance!  E-mail response is probably okay as no one else
seems to miss NOAA-9 APT service.

frank
..cs.utexas.edu!ut-emx!frank
(512)-244-0625 Home ans machine.

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

End of SPACE Digest V9 #536
*******************