Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_1/V16NO102.TXT

Internet Message Format | 1993-07-13 | 34KB

Date: Sun, 31 Jan 93 05:33:56
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #102
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 31 Jan 93       Volume 16 : Issue 102

Today's Topics:
                             Beanstalk?+
                        Challenger transcript
          Clinton's Promises (space) in Charlotte Observer+
                          Death and Tragedy
                 Goals for year 2000. I have a dream.
                         IRAS - 10 Years Ago
                    JPL Mission Updates - 01/27/93
                             Mars Mission
                     Microgravity Research Today
                          Precursors to SSF
                Shuttle Challenger 1986, Where I was..
                      Solar Sail/Parachute/Brake
                         Solar Sail formulae
            Today in 1986-Remember the Challenger (2 msgs)
                    Using off-the-shelf components

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: 30 Jan 93 18:20:24 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Beanstalk?+
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (Gary Coffman) writes:
>> In article <[e-mail]> [e-mail] writes:
>>>Does anyone know anythng about how to build a beanstalk?
>>
>> First you get some magic beans.....
>
>Real funnt, eh Gary..
>
>I mean the one that is teethered in space (geo orbit) and wher a cable is sent
>into the atmosphere and teathered to the earth.. You then use the cable to send
>cargo up and down from space..
>Basically a elevetor on a cable..
>Does anyone know more and if we are anywhere nearer the Tech for it than we
>were a few years ago.. Anyoen think it might be possible?

Yes I knew what you meant Michael. A constant taper beanstalk is beyond
the theoretical strength of materials of anything we have a clue about
producing. A tapered beanstalk is theoretically possible, but would be so
huge that it would be impractical to construct. A very long thread on
this subject occurred here last summer.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: Sat, 30 Jan 1993 12:48:06 -0500
From: Tim Tyler <[e-mail]>
Subject: Challenger transcript
Newsgroups: sci.space

Hi All!

29 Jan 93 22:58, Tesuji wrote to All:

 T>   A secret NASA tape reveals that the crew of the shuttle Challenger
 T> not only survived the explosion that ripped the vessel apart; they
 T> screamed, cried, cursed and prayed for three hellish minutes before
 T> they slammed into the Atlantic and perished on January 28, 1986.

 T>   The tape is said to begin with a startled crewman screaming,"What
 T> happened? What happened? Oh God - No!"  Screams and curses are heard-
 T> several crewmen begin to weep- and then others bid their families
 T> farewell.

 T>   Two minutes forty-five seconds later the tape ends. That's when the
 T> shuttles crew compartment, which remained intact after the vessel
 T> exploded over the Atlantic, hit the ocean at over 2,000 miles per
 T> hour, instantly killing the crew.

Well, that and the rest of that post was certainly the most tasteless thing I've seen here in ages...

=======================================================================
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SysOp: Timothy S. Tyler                         :  It's the end of the
FidoNet 1:374/48.0 [phone]               :  world as we know it
Packet: -----------------------------           :  and I feel fine...
Internet: [e-mail]     :
=======================================================================

 * Origin: FarPoint v32b/v42b >407-631-9198< FIDO.UUCP.SFNET (1:374/48)

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

Date: 30 Jan 93 14:17:45 GMT
From: [e-mail]
Subject: Clinton's Promises (space) in Charlotte Observer+
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Edward V. Wright) writes:
> In <[e-mail]> [e-mail] (Doug Mohney)
> writes:
>
>>    C) How do you set the damned thing up without using goverment help
>>       in the first place? Guess who owns all the big launch facilities.
>
> Aw, yes, the ultimate fallback argument.
>
> The government owns all the launch facilities because the
> government crushes anyone who tries to compete with them.
>
> It justifies its strong arm tactics by saying that launch
> facilities are a "national resource" -- without government,
> there would be no launch facilities.
>
> Perfect circular reasoning.
>
>

Sounds liek the same argument the FED has for making sure that alaska can only
sell its oil to US Companies (Namely in Texas and California) and that we can't
sellt eh oil at compedative prices, but we have to sell for lower..
Because the oil is a Amerina Resource.. Sounds more like National Socialism in
its infancy..

The democracy never existed, the republic is dead, now comes the socialist
state..Then the empire.. When will the bread and circuses begin, see welfare..
All we need is government sponsored gladitor fights and we would be ......


end of transmission

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

Date: 30 Jan 93 18:30:51 GMT
From: Josh Hopkins <[e-mail]>
Subject: Death and Tragedy
Newsgroups: sci.space,sci.space.shuttle

[e-mail] (Doug Mohney) writes:

>There's a difference between dying in prime time with the world watching a
>unique event verses a twenty second one-time on the local news coverage verses
>a two column inch notation on page B3 of the local paper.

>Consider the 120-plus people who died during Desert Shield/Storm operations.

This line reminds me very much of the belief that there were no survivors of
Custer's Last Stand.  Hundreds of thousands of Iraqis died in Desert Storm.
Plenty of Indians survived Custer.  Our perceptions of death depend not only
on how how media friendly the events are but also on which media we get our
information from.

Was Challenger a tragedy?  That depends on your definition.  As I recall, the
Greek definition of tragedy was when bad things happen to good (but fallible)
people.  If perfect people or jerks suffer no one really cares.  And if the
calamity is an "act of God" then it's unfortunate but unavoidable.  I think
Challenger does fit this classic definition of tragedy.  Good people died
because other good people made a reasonable mistake.  I don't think the fact
that test pilots die on a regular basis makes their deaths any less tragic.

Anyone who wishes to refute me is welcome to do so.  But I'd appreciate it if
someone would remind me which Greek text I was reading.

--
Josh Hopkins                                          [e-mail]

Q:  How do you tell a novice from an expert.
A:  A novice hesitates before doing something stupid.

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

Date: 30 Jan 93 14:02:12 GMT
From: [e-mail]
Subject: Goals for year 2000. I have a dream.
Newsgroups: sci.space

How about this for a Goal. SSTO, SSF, Mars Mission to Mars and Solar Sail
Race to the Moon or ?  By the year 2000, its not that far off..

So far what I have seen of NASA and the discussions here, no one has a combined
plan of what is going on and what our goal is.. I think we need to maybe have
the dream of Kennedy to have all the above and maybe more by the end of the
millenia...

==
 Michael Adams, [e-mail]
 Im not high, just jacked

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

Date: 31 Jan 1993 00:44 UT
From: Ron Baalke <[e-mail]>
Subject: IRAS - 10 Years Ago
Newsgroups: sci.space,sci.astro,alt.sci.planetary

From the "JPL Universe"
January 29, 1993

IRAS: 10 years ago, infrared widened our eyes
By Mary Hardin

     Ten years ago this week, the launch of the Infrared
Astronomical Satellite (IRAS) made history as the first
spacecraft designed specifically to study the universe at
infrared wavelengths.
     "IRAS opened the entire Milky Way to our view, revealing
previously unsuspected phenomena and providing new probes of the
structure of the galaxy," said Dr. Charles Beichman, director of
JPL's Infrared Processing and Analysis Center (IPAC) and a member
of the IRAS science team.
     The satellite was an international project involving The
Netherlands, the United Kingdom and the United States, but its
early life was so full of problems it almost didn't get off the
ground. To begin with, the project was two years and tens of
millions of dollars over budget due to problems with the
detectors, the telescope and the cryogenic valves. There were
also some fears that the cover would not come off the telescope,
and if it did, that the mirror would be covered with nitrogen
frost. Despite these concerns, the spacecraft was launched, and
after a troubled start, it began producing a steady stream of
data.
     To ensure that the satellite was sensitive to the infrared
heat coming from deep space, the spacecraft carried 700 liters of
superfluid helium to cool the telescope and detectors to a
temperature of 2 degrees Celsius above absolute zero. After 10
months in orbit, the helium evaporated and the data-taking
portion of the mission was over.
     But the data-analysis phase was just beginning. From its
vantage point above the glare of Earth's atmosphere, IRAS
produced more than 600,000 individual objects and more than 1,600
images of the entire sky. All told, the IRAS mission has helped
astronomers make many startling discoveries.
     "IRAS found more evidence for planet building among mature
stars," Beichman said. "One of the great surprises of the mission
was that Vega, one of the brightest visible stars in the sky, was
10 times brighter in the infrared than predicted. The infrared
radiation coming from Vega, and similar stars, is consistent with
a ring or disk of solid material orbiting the central star. IRAS
found that one-quarter of all stars have this same phenomenon."
     Another surprise was the number of galaxies it revealed. "No
one expected IRAS to find more than 1,000 galaxies, but we found
60,000," Beichman exclaimed. "These galaxies have been used to
probe the overall structure of the universe. One IRAS object may
be a galaxy captured in the process of formation.
     "IRAS was also a prolific comet finder, having detected
about 25 of them," he continued.
     Observations of these objects have changed the way
scientists think about comets. Prior to IRAS, astronomers thought
comets were large balls of ice hurtling through space. IRAS
showed that comets are made of mostly dirt and rock, with an icy
covering.
     The wealth of data produced by IRAS is used in ongoing
research by astronomers from around the world.
     "IRAS revealed the infrared sky to us in the way people will
be looking at it for a long time," Beichman said. "It is our
first and only view of what's out there until somebody does it
better. And it's not going to be easy to do it much better than
we did."
     That opportunity to follow up on many of the IRAS
discoveries will come sometime after the turn of the century,
when JPL's Space Infrared Telescope Facility (SIRTF) is launched
into solar orbit. SIRTF will take advantage of the enormous
technical advances in infrared detector arrays that have been
made over the last decade, making it 1,000 times more sensitive
than IRAS.
     However, SIRTF may lack a bit of magic that came with its
predecessor. "After all, one can open one's eyes to the night sky
for the first time only once," Beichman concluded. That honor
will forever belong to IRAS.
                           ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

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

Date: 31 Jan 1993 00:41 UT
From: Ron Baalke <[e-mail]>
Subject: JPL Mission Updates - 01/27/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

                    PLANETARY MISSION STATUS
                        January 27, 1993

VOYAGER 1 and 2: The two Voyager spacecraft continue their
interstellar mission with fields-and-particles data acquisition.
Voyager 1 was launched September 5, 1977, is currently 7.6
billion kilometers (4.7 billion miles) from the Sun after flying
by Jupiter and Saturn in 1979 and 1980; Voyager 2 was launched
August 20, 1977, flew by Jupiter (1979), Saturn (1981), Uranus
(1986), and Neptune (1989), is now 5.8 billion kilometers (3.6
billion miles) from the Sun.
Contact: Mary Hardin, [phone].

MAGELLAN: The Magellan spacecraft is continuing its survey of the
gravitational field of Venus, utilizing precise navigation of the
spacecraft in the near-Venus portion of its orbit through May 15,
1992.  Magellan was launched May 4, 1989, aboard Space Shuttle
Atlantis with an IUS injection stage.
Contact: Jim Doyle, [phone].

GALILEO:  The spacecraft is now en route to Jupiter, scheduled to
go into orbit there on December 7, 1995.  It completed its second
Earth gravity assist on December 8, picking up the last increment
of velocity for the Jupiter flight.  Spacecraft performance and
condition are excellent except that the high-gain antenna is only
partly deployed; science and engineering data are being
transmitted via the low-gain antenna.  An operation intended to
free the high-gain antenna by pulsing the antenna-deployment
motors began in late December and concluded January 19 without
success.  The Project will now focus on completing the Jupiter
mission using the low-gain antenna.  Galileo was launched October
18, 1989, by Space Shuttle Atlantis and an IUS, and flew by Venus
and Earth in 1990 for earlier gravity assists.
Contact: Jim Wilson, [phone].

ULYSSES: The spacecraft is in a highly inclined solar orbit, now
almost 17 degrees south of the ecliptic plane, in transit from
its Jupiter gravity assist in February 1992 toward its solar
polar passages in 1994 and 1995.  Its condition and performance
are excellent, and it continues to observe the interplanetary
medium.  The Ulysses spacecraft was built by the European Space
Agency and launched October 6, 1990 aboard Space Shuttle
Discovery, with IUS and PAM-S stages.
Contact: Diane Ainsworth, [phone].

TOPEX/Poseidon:  The satellite is healthy, and all scientific
instruments are performing normally, typically providing three
playbacks per day.  To date, eleven 10-day science-data cycles
have been collected for processing and verification as planned.
TOPEX/Poseidon was launched August 10, 1992, aboard Ariane 52.
Contact: Mary Hardin, [phone].

MARS OBSERVER:  Spacecraft health and performance are normal, and
Mars Observer is on its planned trajectory leading to Mars orbit
insertion August 24, 1993.  It is now in the "outer cruise"
flight mode, with communications on the high-gain antenna. The
scientific instruments are being checked out on schedule.  The
second TCM is planned for February 8.  Mars Observer was launched
aboard a Titan III/TOS vehicle on September 25, 1992.
Contact: Diane Ainsworth, [phone].

                              #####
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

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

Date: 30 Jan 93 23:57:59 GMT
From: Greg Moore <[e-mail]>
Subject: Mars Mission
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>From: George Hastings <[e-mail]>
>
>Micael Adams sez;
>>>Im not sure if this idea is feasible, but, its an idea..`
>>>What about pre-positioning feul/food/gear packets along the route of the Mars
>>>mission or maybe send a unmanned mission ahead maybe by Solar Sailer(s).
>>>And pre-[.positioning the craft to be near na..mars when the Mir mission
>>>arrives at Mars.
>
    [objection due to orbital mechanics changing positions]

>Sure, it's a trick, but it's just a matter of positioning in time
>as well as space.  If NASA could guarantee schedules better...
>
>To first approximation, it's only a 3-d problem, since the extra
>time dimension is balanced by the fact that the route would be
>a 2-d one (roughly).
>
>Still, resupply being pre-positioned at the destination would be
>a lot easier.
>
    Yes, it would, but not for the reason mentioned above.

    Let's say you time things, and the fuel/food caches
are right along your path when and where you need them.
    But either A), they aren't moving at your speed.  This

means you must either slow down to get them and speed back up,
or grab them (some sort of hook and line).  Either way, you lose
energy (since you're adding mass).
    Or, B) they're moving at your speed.  In which case
you don't loose energy.  But, you've already spent that energy
getting them there and up to their speed.

    The only real advantage I can see is if you use a
cheap and slow acceleration to get them up to speed and in
position.  (Say a solar sail or electric proplusion) and
use a faster costlier acceleration method for your manned
craft.

    However, caching your supplies AT your destination
makes a LOT more sense.  Then, if you do get slowed down, you don't
have to worry about missing them.  Also, rendevous would be
simpler.

>-Tommy Mac
>------------------------------===========================================
>Tom McWilliams               |Is Faith a short '  `      '   *.;     +%
>[e-mail]       |cut for attaining    +    .      '
>[phone] -or- 353-2986 |  . knowledge? ;"'       ,'    .   '     .
>a scrub Astronomy undergrad  |      *     ,    or is it just  .       .
>at Michigan State University |   ';   '        * a short-circuit?   ,
>------------------------------===========================================

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

Date: 30 Jan 93 18:24:01 GMT
From: "H.A. Collier" <[e-mail]>
Subject: Microgravity Research Today
Newsgroups: sci.med,sci.bio,sci.materials,sci.space

I don't know much about microgravity, but I do know of a scientisit who
works at NASA here in Houston (Clear Lake) on it. His name is David Wolfe.
I don't know him personally, a colleague of mine does.
I believe Dr. Wolfe is scheduled to fly in an upcoming shuttle mission
sometime this year, testing some microgravity techniques.
If he has email you may be able to find it.

Heidi

--
Heidi Collier                     Internet: [e-mail]
Dept of Otolaryngology
Baylor College of Medicine
Houston, TX  77030

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

Date: 31 Jan 93 00:25:42 GMT
From: Steinn Sigurdsson <[e-mail]>
Subject: Precursors to SSF
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:

   One problem for which no solution has been found yet: in-orbit fax machines.
   If SSF uses the same fax design as the Shuttle, and they want to have a
   working fax most of the time, then they'll have to ship up 52 new fax machines
   a year. One good feature of this - as each fax machine jams, it can be
   lowered from SSF by tether, thus reducing the orbital debris problem, and
   boosting SSF's orbit at the same time. :-)  :-)  :-)

   (I haven't finished analyzing the tapes from STS-54 yet, but I haven't heard
   of the fax machine jamming on that mission. If in fact they had the fax on
   board and used it, and it *didn't* jam, that would be a major milestone! :-)

Well, if they must stay with obsolete technology (presumably to stay
in touch with NASA HQ and the NSC ... say, maybe that's why they keep
breaking...) then why not save the weight of paper and use a 9600b/fax
modem that reads straight to file? Cut out the dead tree portion
altogether.


|  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: 30 Jan 93 13:50:51 GMT
From: [e-mail]
Subject: Shuttle Challenger 1986, Where I was..
Newsgroups: sci.space

Where was I when the challenger blew up..

I came home that day from work, turned the TV on and there it was..
I think it blew up sometime around the time I was jetting down the highway in
Anchorage Alaska on my way to Fort Richardson to get some stuff fromt eh PX or
something.. Wow is has been 7 years already. Where has the time and shuttle
gone?

Well all, here is to the future, hoep its better and brighter than today..
Heres to the Shuttle Seven, they are truely Rocket "men" (sorry not ment to be
sexist)..

==
 Michael Adams, [e-mail]
 Im not high, just jacked

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

Date: Sat, 30 Jan 1993 17:52:55 GMT
From: Josh Hopkins <[e-mail]>
Subject: Solar Sail/Parachute/Brake
Newsgroups: sci.space

[e-mail] (Jonathan Deitch) writes:

> >From: [e-mail]

> >A Solar Sail if I understand right when it arrives at its Steller destination
> >it becomes a Solar Parachute/Brake. Am I right?

>Yep ... you simply turn it around and use it to capture the *outward* solar
>wind of your destination star to slow you down.

Solar sails do NOT use the solar wind.  They run on light pressure.

--
Josh Hopkins                                          [e-mail]

Q:  How do you tell a novice from an expert.
A:  A novice hesitates before doing something stupid.

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

Date: Sat, 30 Jan 93 20:28:46 EST
From: John Roberts <[e-mail]>
Subject: Solar Sail formulae

#From: [e-mail] (Marcus Lindroos INF)
#Subject: Solar Sail Formulae-help needed!!
#Date: 29 Jan 93 09:43:39 GMT
#Organization: Abo Akademi University, Finland

#On the subject of solar sails, I found these formulae in a Finnish space
#magazine. Now, since neither Finnish nor English is my first language, I can't
#guarantee that I got everything right when translating this:

##1: "Pressure produced by sunlight hitting a solar sail"

#p=E(k+1)/c    where E=Energy
#                    k=reflectivity factor(?)
#                    c=speed of light

That's correct if you use MKS units - energy is watts per square meter,
pressure is Newtons per square meter, and k is reflectivity (0 for completely
nonreflecting, 1 for completely reflecting.) It has to be a specular reflection
rather than a diffuse reflection for this to work. It assumes that the sail
is flat, and the rays from the sun are completely parallel and perpendicular
to the sail, so the formula is off by the extent to which these assumptions
aren't completely accurate. Very close to the sun, it could be off by as
much as a factor of two.

##2: Acceleration

#as=(1+k)*1*10^17 As/Mr^2      where As = Sail area
#                                    M  = mass of sail+spacecraft
#                                    r  = Distance from Sun

The basic idea's correct, but I don't know about that multiplier (no units
are specified anyway). Instantaneous acceleration is directly proportional
to (1+k) and to sail area, and inversely proportional to mass and the square
of the distance from the sun (approximately). The formula appears to leave
out the gravitational attraction between the sun and the spacecraft, which
at the magnitudes involved in solar sailing is significant.
Putting in gravitational attraction, the formula should be something like:
    acceleration = (constant * (1+k) * As / Mr^2) - (Ms * G / r^2)
where Ms is the mass of the sun, and G is the gravitational constant.
Note that there's a minimum surface area per unit mass below which you
can't use photon pressure to accelerate directly away from the sun, though
that doesn't rule out tacking from a solar orbit (a whole other set of
equations). That minimum is pretty much independent of the distance from
the sun.

#------------------------------------------------------------------------
##3: Final velocity for a solar sail making a close flyby of the Sun:

#v=((1+k)^2 * 2 * 10^17As -2.66 * 10^28M) / Mr0 + v0^2) ^ 0.5

#                              where r0 = Distance at periastron(/helion?)
#                                    v0 = Velocity at periastron

#v0 can be calculated from :

#        I     radius^2                        2*aphelion dist.              I
#v0=SQRT I--------------------------------- * -------------------------- * G I
#        I distance at perihelion            aphelion dist.+perihelion dist. I


#Marcus Lindroos                             Internet:     [e-mail]
#Computer Science
#Abo Akademi University
#Finland

Good luck on #3 - I'm not willing to tackle it without MKS units.

John Roberts
[e-mail]

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

Date: 30 Jan 1993 18:12:41 GMT
From: James Michael Sambrook <[e-mail]>
Subject: Today in 1986-Remember the Challenger
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John A. Weeks III) writes:

    {Written by yours truly...}
>> Where was I when the Challenger accident occurred?
>> To this day, I still get chills when I see the explosion.  Let's ALL
>> hope that it never happens again...
>
>Lets also keep in mind that zero risk means zero progress.  In order to
>make progress, we are going to have more accidents.

I agree 100 percent.  I am not in any way, shape or form saying that the space
program should be halted just because of the Challenger Explosion...We learn
by our mistakes.  It is a shame when these mistakes cost people their lives.

>Each day dozens of people get cancer from smoking and we pour tons of
>smoke in the air producing electricty, yet the entire planet comes to
>halt when we have a space related accident.  I would not be surprised
>to hear that hundreds of people on planet Earth died of starvation on
>the day of the Challenger accident, or that 7 children were beaten to
>death by their parents.  When put in perspective, the Challenger accident
>was a minor problem compared to the problems we face every day in life.

I agree.  However, we will never know about these people, simply because (and
please, no flames for this comment) we didn't know them.  It seemed as though
everyone was somewhat familiar with the astronauts in the Shuttle on this
particular flight (even more than normal due to the "Teacher-in-Space")
program.  It affects us all more profoundly if, when we hear about a plane
crash where 250 people died, if one of those 250 people was a friend or a loved
one.  It's the truth.  It may be sad...but it's the truth.
Besides, we never hear any jokes about the children getting beaten to death by
their parents, but the day after the Shuttle exploded, I heard:

Q : "What does NASA stand for?"
A : "Need Another Seven Astronauts"

Q : "Who will the second civilian in space be?"
A : "A substitute teacher"

I think that these "jokes" are even worse than the accident itself because this
is WILLFUL.

>We can never be perfect and we can never control all of the variables.
>The seven people who perished in the Challenger accident should be,
>above all else, our inspiration to keep flying.

Again, I agree 100 percent.

                        James Sambrook

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

Date: Sat, 30 Jan 1993 23:07:25 GMT
From: Steven Eitzen <[e-mail]>
Subject: Today in 1986-Remember the Challenger
Newsgroups: sci.space,sci.space.shuttle

In <[e-mail]> [e-mail] (Simon E. Booth) writes:


>So, where were you when the Challenger disaster took place?

I was in the lunch hall at school during grade 8 when I found out. One of the
hall monitors came in and told me about the disaster. Was all I could think
about the rest of the day.
--
Steve Eitzen                                    | "For every action,
Vice-President - U of M Campus Computing Assoc. |  there is an equal
Internet: -Unix: [e-mail]      |  and opposite campus
          -TSO:  #[e-mail]       |  Rent-a-cop."

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

Date: Sat, 30 Jan 93 21:18:06 EST
From: John Roberts <[e-mail]>
Subject: Using off-the-shelf components

-From: [e-mail]
-Subject: Re: Using off-the-shelf-components
-Date: 27 Jan 93 23:13:00 GMT
-Organization: University of Houston

-In article <[e-mail]>, [e-mail] (Ata Etemadi) writes...
-> Are there any companies out there whose off-the-shelf products are
->space-qualified ? I ask this since a colleague at IKI told me that
->they had flown many standard PC hard discs as onboard storage devices
->and had great success. I just wondered what other components might be
->out there which are standard and space-qualified. I don't imagine
->for one minute that these components will be chosen for major space
->missions since they are just not expensive enough. Maybe the UOSAT
->folks will be willing to give them go...

-You know I feel like I am the Shell Answer man for space of late.

Your detailed information on your projects and on Shuttle operations is
greatly appreciated.

-You can fly any commercial hardware you like on the shuttle as long as it
-meets the flamablity, outgassing, offgassing and EMI requirements.

-Let me give you an example. I recently, along with others working at the
-University of Alabama in Huntsville, built tested and delivered to the
-SpaceHab module (STS 57) a major payload for the measurement of the
-microgravity levels inside of the SpaceHab module.  This experiment has
-a controller that is a personal computer that sit by the millions on desks
-all across the world, with a data acquisiton card manufactured commercially
-by the US leader in that field. Also flown for data storage are two 2.1
-gigabyte ST42100 5 1/4" Seagate hard disks. Attached to this are some rather
-expensive accelerometers that are the best in the world.  The software is
-a standard version of the commercial data acquistion software made by the
-manufacturer of the data acquistion card.

I hope your payload can work acceptably if one of the two hard drives fails.
>From keeping track of previous Shuttle missions, it appears to me that
standard hard drives generally work in microgravity, but for some reason
they're much less reliable on the Shuttle than on the ground. If it can
work with one, then including two drives was a very good idea.

Any chance of finding out the maker of the data acquisition card and the
interface it connects to? I sometimes need to know that sort of thing in
my work. Email would be fine.

-These components were integrated into a structure that fits in a Middeck
-locker and all of the above components passed the shake tests, outgassing
-and offgassing tests, as well as near compliance on EMI which  required a
-waiver, which was granted.

What is offgassing?
        ---

-Dennis, University of Alabama in Huntsville

Another factor that affects some LEO missions is radiation, particularly
when the orbit is fairly "high" altitude and when the spacecraft passes
through the South Atlantic Anomaly. From a lecture I heard a few months
ago given by one of the HST hardware people, the SAA still tends to
scramble some of the electronics whenever HST passes through it. Fortunately,
they've taken measures to minimize the consequences, but still I don't think
observations can be conducted during this interval. For really critical
situations like Galileo (which has to operate in the high-radiation
environment of Jupiter, and which can't afford an upset during orbital
insertion), greater levels of radiation hardening are available.
Though I don't know for sure, I'd guess that STS-57 won't have to go too
high to retrieve EURECA (I understand that it's supposed to lower itself
to an orbit of about 160 nautical miles for pickup), and it doesn't sound
like your experiment has to run *all* the time to be successful. Also,
the Shuttle provides considerable radiation shielding to its interior.

John Roberts
[e-mail]

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End of Space Digest Volume 16 : Issue 102
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