Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_9/v16no993.txt

Text File | 1993-08-13 | 18KB | 399 lines

Space Digest                Fri,  6 Aug 93       Volume 16 : Issue 993

Today's Topics:
                      engine failures and safety
Fractional Millikans (was Re: Cold Fusion and its possible uses) (3 msgs)
                      Magellan Update - 08/05/93
                     Mars Observer's First Photo
               Mars Observer Update - 08/02/93 (2 msgs)
            Simple Space Plane! Fuel other than Kerosene!?
                 The Inquisition (The Usenet edition)
                       Titan IV failure. Info?

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

Date: 6 Aug 1993 08:16:08 GMT
From: George William Herbert <[e-mail]>
Subject: engine failures and safety
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>I'll admit to having been a bit grumpy when I posted that... :-)
>
>Note, though, a more general point:  when an airliner loses *all* its
>engines, it better get at least one of them relit, or it's going to
>crash unless the gods are really smiling.  When you're out over the
>Pacific at night and run into a Pinatubo ash cloud, the engines are
>at least as important as the wings -- without engines, wings just
>postpone the inevitable briefly.

True.  However, all-engine failures are pretty rare in both planes
and rockets.  Offhand, I remember that one 747 in the ash cloud,
(very nearly) the DC-10 with the oil leaks in all 3 engines, the
(727?) from columbia that ran out of fuel and crashed in NY, and the
Canadair 767 which suffered from metric-conversion induced fuel
starvation but lucked out and landed intact on a racetrack. 8-)

>Sure, in particularly favorable conditions -- nearby long hard-surface
>runway, pilot who flies gliders as a hobby -- an airliner can survive
>an unpowered landing.  And in particularly unfavorable conditions, even
>having two or three surviving engines won't help enough.  But in the
>average situation, one engine out is okay and all engines out is lethal,
>wings or no wings.

Of the four cases I can recall, three landed intact, two of them
at airfields.  This is reasonably good odds.

Of course, in rockets the equivalent failure modes would have been
2/4 crashes;  the Pinatubo cloud 747 and the DC-10 analog situations
are survivable, but any rocket is gonna come down hard if you run out
of fuel, no matter what's underneath you or what hobbies you have.
An analogous situation would be non-restartable failures in all motors.

Still pretty good odds.  Assuming you have restart capability in your
motors, and that they're seperated enough that a catastropic 1-engine
failure doesn't cascade, you can make a pretty safe rocket.

-george william herbert
Retro Aerospace

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

Date: Fri, 6 Aug 1993 04:58:50 GMT
From: Leigh Palmer <[e-mail]>
Subject: Fractional Millikans (was Re: Cold Fusion and its possible uses)
Newsgroups: sci.physics,sci.space

In article <north.744568375@watop> Mark North, [e-mail] writes:
>Well, sure enough, there did seem to be
>peaks at 1/3 and 2/3 charge. As I recall it caused a minor stir until
>someone came up with a reason that had nothing to do with quarks.
>Damned if I can remember what though.

Reminds me of the story about the physics professor and the coed and her
three-legged pet rabbit.

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

Date: Fri, 6 Aug 1993 06:05:20 GMT
From: Leigh Palmer <[e-mail]>
Subject: Fractional Millikans (was Re: Cold Fusion and its possible uses)
Newsgroups: sci.physics,sci.space

In article <[e-mail]> Phil G. Fraering,
[e-mail] writes:
>Or that a couple of careful professionals could devise an improved
>apparatus that would have less noise.

In the same Physics 110C lab at Cal where I did my conventional oil-drop
measurements there was an apparatus using a horizontal E-field and a strobe
light, taking data photographically. I didn't know anyone who ever got that
crossed-field apparatus to work.

Leigh

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

Date: Fri, 6 Aug 1993 09:02:49 GMT
From: "Michael D. Crawford" <[e-mail]>
Subject: Fractional Millikans (was Re: Cold Fusion and its possible uses)
Newsgroups: sci.physics,sci.space

In article <[e-mail]> [e-mail] (Paul Callahan) writes:
>... it seems to me that there is
>a delay of about a fifth of a second for a human to react to even the
>simplest of stimuli.  This was quite a significant length of time
>compared to what we were recording.  Now, I suppose there is a delay
>both in starting and stopping a timer, causing some cancellation, but
>this strikes me as a horrible thing to rely upon (I don't know the
>conventional opinion on this).  I realize the original experimenters
>had to make due with what they had, but they also had a lot more time
>to try to get the experiment to work.  Something like stroboscopic
>pictures, or even an automatic detector would seem more reasonable to
>me, though I suppose it may not be feasible to make such equipment
>available to classes.

I recall now that when I did the experiment I was often not sleeping, and
so my reaction time was highly variable.  Sitting in the dark room
required for the experiment would allow me to driff off while watching
my little drop move back and forth.

I think a fairly simple modification that would work with most existing
apparatus would be to use a video camera and VCR to observe the drop.
If the frame number were recorded on tape the times would be easily
accurate to a 30th of a second, and not be dependent at all on reaction
time.

One could calibrate verticle distance vs. video scan line (assuming the
lens is free of distortion) and so make fairly good distance measurements
as well.  (In fact, I wonder if the microscopes that are typically used
are free of distortion - perhaps this is a significant source of error).

Another problem is the agility problem - sitting in the dark and toggling
switches, getting the measurement of the voltage, trying to operate the
perfume bottle to get a nice drop.  Having a VCR would allow the lights to
stay on and eliminate the need to spends hours staring into the microscope
in an uncomfortable position.

The real key to the experiment is to uncover the sources of systematic
error and eliminate them, but this experiment is so awkward that I think
few undergraduates are able to take the time needed to do it well.  Just
arranging some simple things for the comfort of the experimenter would
remove a lot of human error and allow time for attention to the machine's
error.

(It could be that the main benefit to me of doing this experiment is
learning the importance of a good experimental setup.  If I'd had such a
nice apparatus when I did it, I would have gotten better results, but
we already know the charge on the electron - the aim is to educate the
student.  I do think that students in an undergraduate lab should have
the option of spending the whole term on a single experiment, with access
to a machine shop and basic electronics tools so they can spend time
improving the experiment).

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

Date: 6 Aug 1993 05:37 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 08/05/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                          MAGELLAN STATUS REPORT
                              August 5, 1993

1.  EOTMs 3, 4 and 5 (Exit Orbit Trim Maneuvers) to further raise Magellan's
periapsis will be performed today on three consecutive orbits beginning at
about 11AM PDT.  Each EOTM will raise the periapsis by 14 km with a final
level at 205 km.

2.  All spacecraft subsystems are nominal.  The solar panels shows no effects
from the 70 days of exposure to the harsh environment of drag passes.

3.  The Magellan Transition Experiment demonstrates a significent new maneuver
technology by achieving a major orbit change with minimal propellant and
enabling new scientific observations near the poles of Venus.

4.  Circular orbit operations will begin August 16th with a command sequence
with emphasizes data gravity acquisition near the poles of Venus.  Although
the final orbit following the EOTMs is relatively stable, it will change in
response to local gravity and atmospheric variations.  Over the 14 months
proposed for the Lean Mean Gravity Team extended mission, the perapsis will
drift from 200 down to 155 km and back up to 194 km.  The orbit period will
vary by as much as 20 seconds.  This orbit will extend the excellent gravity
data collected by Magellan near Venus' equatorial lattitudes to the whole
globe.

5.  As of next Tuesday, August 10, the 3rd anniversary of Magellan's arrival
at Venus, the spacecraft will have orbited 8350 times and travelled almost
550 million kilometers around the planet.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | When given a choice between
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/  |_|/       |_____|/                     | the one you haven't tried.

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

Date: 6 Aug 1993 05:55:09 GMT
From: Carl J Lydick <[e-mail]>
Subject: Mars Observer's First Photo
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
=In article <[e-mail]> [e-mail] (Richard D Pierce) writes:
=>>     The B & W photograph is available by calling NASA's
=>>Broadcast and Imaging Branch ...
=>
=>And, of course, it's available by FTP, right?
=
=That's either sarcasm or naivete; no way to tell which. :-)
=
=It won't be available for FTP until somebody gets a copy and scans it in.
=NASA's PR people are still in the dark ages when it comes to electronic
=availability of such things.

The abvove demonstrates a profound ignorance of NASA.  For some missions, at
least, the photos are available via FTP long before they're available as
hard-copy.
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: [e-mail] | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.

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

Date: Fri, 6 Aug 1993 05:45:19 GMT
From: julie moses <[e-mail]>
Subject: Mars Observer Update - 08/02/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

>>>>>> On Wed, 4 Aug 93 21:42:50 GMT, [e-mail] (Stefan Michalowski) said:
>
>SM> Question: why does Mars Observer have such an unattractive/unconventional
>SM> name? With some exceptions (Lunar Orbiter - yawn) our probes seem to
>SM> get nice names like Galileo and Viking. What's the story?
>
Mars Observer Mission -- MOM.  You can't get much more attractive or
conventional than calling it after everyone's mother! B-)

                    Julie

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

Date: Fri, 6 Aug 1993 07:08:56 GMT
From: Dave Michelson <[e-mail]>
Subject: Mars Observer Update - 08/02/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> [e-mail] (julie moses) writes:
>
>>SM> Question: why does Mars Observer have such an unattractive/unconventional
>>SM> name? With some exceptions (Lunar Orbiter - yawn) our probes seem to
>>SM> get nice names like Galileo and Viking. What's the story?
>>
>Mars Observer Mission -- MOM.  You can't get much more attractive or
>conventional than calling it after everyone's mother! B-)

Good point... though it probably fits TDRSS better :-)

--
Dave Michelson  --  [e-mail]  --  University of British Columbia

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

Date: Fri, 6 Aug 1993 06:24:30 GMT
From: [e-mail]
Subject: Simple Space Plane! Fuel other than Kerosene!?
Newsgroups: sci.space

Okay so Kerosene is out. REF: post about it earlier.

What other fuels can be used to make a jet than can be covered inflight to a
rocket. With internal oxygen, once the air is to thin..

===
Ghost Wheel - [e-mail]

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

Date: 6 Aug 1993 08:06:22 GMT
From: George William Herbert <[e-mail]>
Subject: The Inquisition (The Usenet edition)
Newsgroups: sci.space

[e-mail] (Mary Shafer) writes:
>[e-mail] (Phil G. Fraering) said:
>Phil> [e-mail] (Ward Paul) writes:
>>In article <[e-mail]> [e-mail] (S.H.)
>>writes: > >What is your backgroud?  >Who do you speak for ?  > >What
>>do you do besides writing posters ?
>>Gee, no one told me the inquisition had started again.
>
>Phil> Same here. I didn't expect the Spanish Inquisition.
>
>Nobody expects the Spanish Inquisition!

It's nice to see that everyone's sense of humor remains operational
throughout this debacle... 8-)

-george

"And now for something completely different..."

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

Date: 6 Aug 1993 05:43:00 GMT
From: Josh Hopkins <[e-mail]>
Subject: Titan IV failure. Info?
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>[e-mail] (Josh Hopkins) writes:

Pat posted the article that started this all, but it's gone to article heaven.

>>... I don't think that there is anything downrange of VAFB
>>besides water.  Is it common practice to destroy a rocket that doesn't
>>threaten civilians?

>A rocket running wild under power -- like an SRB cut loose from its core
>stage -- can threaten civilians.  Vandenberg isn't remote enough to avoid
>that possibility.  That's why such rockets *have* destruct systems.

Disclaimer:  I'm not actually disagreeing with Henry, we're just discussing
slightly different things.

I certainly agree that rogue solid boosters ought to have their thrust
terminated if they threaten civilians.  However, I think Pat's suggestion was
that the RSO would have been worried about the second stage.  In this particular
accident, neither of the stages which could be called the "second" stage
should have been producing thrust and I doubt that the liquid engines would
have survived anyway.  The solid boosters should have been fairly close to
burnout (read: much farther along than the Challenger SRBs).  Therefore,
since the Air Force has expressed interest in pulling up the bits to see what
went wrong, I would expect some debate about whether sending a destruct
signal should be necessary.

Mind you, all this stuff is irrelevant if standard procedure is to destory
loose solids as soon as possible.  Does anyone know anything about the details
of Range Safety policy?
--
Josh Hopkins                                          [e-mail]

          He who laughs last probably didn't get the joke.

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


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From: Mary Shafer <[e-mail]>
Subject: Re: The Inquisition (The Usenet edition)
In-Reply-To: [e-mail]'s message of Fri, 6 Aug 1993 02:01:53 GMT
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Sender: Usenet news <[e-mail]>
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On Fri, 6 Aug 1993 02:01:53 GMT, [e-mail] (Phil G. Fraering) said:

Phil> [e-mail] (Ward Paul) writes:

>In article <[e-mail]> [e-mail] (S.H.)
>writes: > >What is your backgroud?  >Who do you speak for ?  > >What
>do you do besides writing posters ?

>Gee, no one told me the inquisition had started again.

Phil> Same here. I didn't expect the Spanish Inquisition.

Nobody expects the Spanish Inquisition!
--
Mary Shafer  DoD #362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                 Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

End of Space Digest Volume 16 : Issue 993
------------------------------