Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_5/V15NO566.ZIP/V15NO566

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Date: Fri, 18 Dec 92 05:06:59
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #566
To: Space Digest Readers
Precedence: bulk


Space Digest                Fri, 18 Dec 92       Volume 15 : Issue 566

Today's Topics:
                           Aurora (2 msgs)
                           DoD launcher use
                    Does Sun have magnetic poles?
                              EVA costs
                         fast-track failures
           Galileo's Atmospheric Probe Passes Health Checks
          Greek jet engine (Was: Terminal Velocity of DCX?)
                           Making Orbit '93
                             Sea Dragon?
                        Shuttle thermal tiles
           Terminal Velocity of DCX? (was Re: Shuttle ...)
                              Warning!!!

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Date: 17 Dec 92 16:38:16 GMT
From: Greg Moore <[e-mail]>
Subject: Aurora
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>>Nah, not isolated enough, rumour seems to be that the forward
>>base is a US NATO base in Scotland.
>
>How about Greenland? The USAF "says" they recently closed three
>forward bases, but who's going to go look?
>
>Gary

    I'll go, I'll go.  Come on guys, how about sponsoring the
great 1993 Aurora Fact0Finding Tour... :-)  I'm looking forward to
spending some time in the winter wonderland.

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

Date: Fri, 18 Dec 92 10:23:09 MET
From: [e-mail]
Subject: Aurora

Steinn Sigurdsson writes (16 Dec 92 15:21:32)

>Nah, not isolated enough, rumour seems to be that the forward
>base is a US NATO base in Scotland.

Could it be the Machrihanish (sp?) base?

J. Pharabod

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

Date: 17 Dec 1992 23:27:23 GMT
From: steve hix <[e-mail]>
Subject: DoD launcher use
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>
>Satellites also have one big advantage no Plane ever will.  Infinite hang time.

Uh...well...geosynch spysats aren't going to be very useful for visual or
IR imaging for anything smaller than, say, large county-sized areas.
Aren't much good for targets very far north (or south).

Non-geosynch orbits give you a different definition of "infinite hang time"
than I'm currently familiar with.

If you want pictures, you'd better be ready to have to wait up to 24 hours
(or more) for your next pass over the point of interest.  Or put up with
having the target *know* when you're going to fly over next. Or use up

varying amounts of (limited) fuel to change your bird's orbit to sneak up
on the aforementioned knowledgable target.

Satellites are a tool.  Not always the best tool.  Sometimes not even a
useful tool.
--
-------------------------------------------------------
| Some things are too important not to give away      |
| to everybody else and have none left for yourself.  |
|------------------------ Dieter the car salesman-----|

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

Date: Thu, 17 Dec 92 19:56:48 GMT
From: Trond Trondsen <[e-mail]>
Subject: Does Sun have magnetic poles?
Newsgroups: sci.physics,sci.electronics,sci.space

In article <[e-mail]> [e-mail] (Babak Sehari) writes:
>[stuff]
>However, if sun should have magnetic poles and if these magnetic poles
>be strong enough, one could use earth rotation around the sun to create
>electric energy. This leads to too small a drop in the earth radius, to
>be noticeable for all practical purposes.  Could someone give us some idea
>about the sun's magnetic field?
>
>                       With highest regards,
>                            Babak   Sehari.
>

Yes, the sun is a magnetic star.  It has a GENERAL dipole field of
about 1E-4T distributed over the visible photosphere.  Apparently,
the dipole direction reverses every 11 years. wow...
The magnetic field convects out with the solar wind (frozen-in), and
near the earth's orbit the intensity is from a few nanoteslas to up to
,say, 20nT when the solar disturbances are great.  The field is mainly
in the ecliptic plane. (BTW; sometimes it happens that there is a small
component perpendicular to the ecliptic plane which can cause an opening in
earth's magnetic field to let particles in and we get aurora and such
interesting phenomena.)


Trond


--
_/_/_/_/ _/_/_/   _/_/_/_/  _/    _/  _/_/        Institute for Space Research
  _/   _/    _/  _/    _/  _/_/  _/  _/  _/           University of Calgary
 _/   _/_/_/    _/    _/  _/  _/_/  _/   _/               LA1OEA/VE6NOR
_/   _/   )_/  _/_/_/_/  _/    _/  _/_ _/             [e-mail]

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

Date: Fri, 18 Dec 92 00:45:59 EST
From: John Roberts <[e-mail]>
Subject: EVA costs

-From: [e-mail] (Gary Coffman)
-Subject: Re: Terminal Velocity of DCX? (was Re: Shuttle ...)
-Date: 17 Dec 92 10:47:48 GMT
-Organization: Gannett Technologies Group

->In article <[e-mail]> [e-mail] (Gary Coffman) writes:
->>Last I heard they're
->>willing to rent Cosmonaut time at $5 million an hour plus launch costs
->>for any experimental equipment you want them to use.

-Oh. Oh. My source is a post by Nick Szabo Sept 19th of last year where
-he quotes a Mir Press article on suited time for sale. Since they offered
-John Denver a ride for $10 million, this must be out to lunch.

Great - I use one of your posts as a reference, and you promptly retract
it! :-)

I presume the John Denver deal didn't involve any EVA, so that doesn't rule
it out yet.

While it wouldn't be fair to divide the cost of an entire Shuttle mission
by maximum EVA time to get US EVA costs, I expect a more reasonable
accounting method would still get a figure up in the millions of dollars
per hour. Don't the EVA suits have a certain maximum number of hours they
can be used per flight?

John Roberts
[e-mail]

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

Date: 18 Dec 92 06:59:58 GMT
From: Nick Janow <[e-mail]>
Subject: fast-track failures
Newsgroups: sci.space

[e-mail] (Gary Coffman) writes:

> When fighter development from concept to flying prototype cost less than
> $100,000, normally funded internally by the company, and took less than a
> year, planes were simpler then, that was an acceptable approach. Now with
> development costs running into the billions, and usually taxpayer funded,
> the financial risks of a failed project have become too high to take such a
> cavalier approach.

I wonder if the development of the hardware might still cost something close
to the 1992 equivalent of $100,000...with the additional billions required
for paperwork, politics, and legal nonsense.  :-/

--

[e-mail]

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

Date: Thu, 17 Dec 1992 22:59:55 GMT
From: Henry Spencer <[e-mail]>
Subject: Galileo's Atmospheric Probe Passes Health Checks
Newsgroups: sci.space,sci.astro,alt.sci.planetary

I wrote:
>>... I also have some knowledge of the
>>accellerations experienced by the Sprint system and HIBEX experiments...
>>none of which came CLOSE to 350G!
>
>Smart artillery shells experience thousands of gees at launch.  A few
>hundred is no big deal...

Note, by the way, that Galileo's 350 isn't even a record.  The steepest
of the trajectories used for the Pioneer-Venus probe mission exposed one
of the small probes to 458.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 17 Dec 92 15:46:44 GMT
From: Dillon Pyron <[e-mail]>
Subject: Greek jet engine (Was: Terminal Velocity of DCX?)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Charles J. Divine) writes:
>In article <[e-mail]> [e-mail] (GRASSO CHRISTOPHER A) writes:
>>In article 26326, (Edward V. Wright) writes:
>>
>>>I think the ancient Greeks, who built a working jet engine,
>>>lived a little more than 50 years ago.
>>
>>Interesting. Would you care to elaborate?
>
>Described briefly, it was a container of water that was heated.  There was an exhaust
>that, when the water was converted to steam, provided a small jet action.  The
>apparatus was rigged to rotate.

Imagine a sphere, mounted on an axle.  Place a nozzle perpendicular to the
axle, fill the sphere with water and light a fire underneath.  If the nozzle is
L shaped, you can make the sphere spin.  The porblem is, if the water is not
hot enough when it starts to spin, the rig will stall at the bottom, water will
gush out and kill the fire.  We built one in my high school physics class.

There is some dispute as to whether such a device was ever built, or just
theorized (I believe it was attributed to Aristotle, but so was everything
else  :-).
>
>The device is impressive intellectually but develops very little real power.
>--
>Chuck Divine
--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
[phone] (when I'm here)     |
[phone] (when I'm home)     |"Pacts with the devil are not legally
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PADI DM-54909                     |-Friar Tuck   _Robin Hood:The Hooded Man_

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

Date: Fri, 18 Dec 1992 05:05:57 GMT
From: "David W. Berry" <[e-mail]>
Subject: Making Orbit '93
Newsgroups: sci.space,rec.arts.sf.announce

It was pointed out to me that I omitted the dates on the Making
Orbit '93 announcement I just posted.

To correct that, it will be 15-18 January 1993.  That's Martin
Luther King weekend 1993.


David W. Berry
Co-Chair Making Orbit '93

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

Date: Thu, 17 Dec 1992 14:06:31 GMT
From: Thomas Clarke <[e-mail]>
Subject: Sea Dragon?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Scott Fisher)
writes:
> [e-mail] (Dennis Newkirk) writes:
>
> >lift-off weight 45,360,000 kg.
>                  ^^^^^^^^^^^^^
>                  |||||||||||||
>                  No way :-)

Why not?  45360 metric tons is less than the weight of
a battleship.

Did you ever see the Japanese cartoon where the beleagured earthlings
convert the battleship Yamato (sunk during WWII, but now dry since the
seas had dried up as a result of the bombardment of earth by the aliens)
into a starship?  The intrepid band takes off, and after many adventures
reach the home planet of the aliens and save earth!  It was actually
pretty clever how the blended the lines of a battleship into a
plausible looking starship.
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
[phone], FAX: [phone], [e-mail]

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

Date: Fri, 18 Dec 92 00:37:49 EST
From: John Roberts <[e-mail]>
Subject: Shuttle thermal tiles

-From: [e-mail] (Mary Shafer)
-Subject: Re: Shuttle thermal tiles
-Date: 17 Dec 92 01:45:28 GMT
-Organization: NASA Dryden, Edwards, Cal.

-On 12 Dec 92 01:24:21 GMT, [e-mail] (John Roberts) said:

-J> The Shuttle launch towers have movable covers which protect the orbiter
-J> from damage by hail and severe storms.

-Dryden flew a number of shuttle tiles (current and proposed) on the
-aerodynamic test fixture on the F-104G.  The tiles are undamaged by
-snow and devastated by rain, with hail being not quite as bad as
-rain.

That's a strange result - this summer I drove through a hail storm
(small hailstones, but a tremendous number of them), and was very impressed
with the impact properties of the hail. It was also raining heavily, but
I believe sometimes there's hail without rain in localized areas.

I suppose in principle you *could* fly through a rainstorm and still land
safely, but it would be a very expensive landing. :-)

-Of course you can cover the vehicle on the pad, but you can't
-fly through rain or hail without etching the tiles down to the felt
-pads they're glued to.

Apparently gentle rain doesn't hurt the Shuttle on the pad. I don't know
to what extent increased weight might be a concern. I believe they spray
water repellant on the tiles prior to launch to minimize water absorption.
The mechanism of damage in flight must be primarily one of abrasion.

Do you happen to recall what kind of glue is used? I got the impression
that it's some variation of RTV (silicone).

-J> It's interesting to recall the extreme concern over the thermal tiles
-J> before STS-1. Many people were convinced that the tiles would all fall
-J> off during reentry. (The fact that Enterprise lost many of its tiles during
-J> transport, and that Columbia lost some off its engine covers during launch
-J> added to the concern.)

-Enterprise, not being a _real_ shuttle, didn't have real tiles.  It
-had a fairly fine-textured plastic foam, painted black.  Not foamed
-ceramic with a ceramic coating, like real shuttles.  I have a small
-chunk of the Enterprise that I picked up off the hangar floor when
-they were doing the structural test evaluations.  These fake tiles
-stayed on very well, both in transport and in flight.

Thanks for the correction - I hadn't realized that the Enterprise tiles
were fake.

-On the other hand, the tiles falling off Columbia during its first
-takeoff on the 747 were thicker than the the leaves falling off the
-fruitless mulberry in my front yard after the first hard freeze last
-month.  I think that the Air Force had a FOD walkdown before they'd
-open the runway after the takeoff.

Maybe it's just as well that Columbia wasn't assembled at KSC. :-)

I believe the solution was dipping the bases of the tiles in something
to make them stronger (and more dense), possibly better glue, and pulling
on every tile to verify adhesion.

I think the Shuttles have actually reentered with a few tiles missing from
the bottom - apparently the heat distribution is such that a few tiles
missing doesn't cause too much damage.

-J> Now it seems to be treated as a solved problem (except
-J> for the weight, of course, and the inability to fly the Shuttle through
-J> rain during landing).

-The various fabrics have replaced the tiles most prone to departure in
-midair.

Is the outer surface of the fabric flexible?

-J> I got to play with some Shuttle tile replicas
-J> at the Technology 2002 conference - they're being promoted as a solution
-J> to some Earth-based problems.

-Did you get to hold it in your bare hand while they played the butane
-torch over it?  It took a lot of faith for me to keep my hand out there
-when the top of the tile started glowing orange.

They had a torch there, but they weren't using it when I walked by.
I got to see that demo once in high school.

Is the method by which Shuttle tile material is made now known to the
public? Does it start out as an aerogel?

John Roberts
[e-mail]

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

Date: 18 Dec 1992 03:13:15 GMT
From: Scott Fisher <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>on several grounds, the low chamber pressures lead to very high
>>loads on the turbopumps because so much more fuel per unit time
>>has to flow to achieve the high thrust required with low pressure
>>engines. Reducing stress in one area can lead to increased stress

>I dont think that is an unsolvable problem.   THe Saturn F-1's sucked
>fuel like no tomorrow.   The soviet's haul fuel to feed those
>big protons and energiya engines.

>I suspect packaging and design are bigger problems  then just mass flow.

Q: What drives the turbo-pumps the rocket exhaust?

If this is so...why can't you bleed some pressure from the exhaust to pressurisethe tanks?  Is this done?

Regards Scott.
_______________________________________________________________________________
Scott Fisher [[e-mail]]  PH: Aus [61] Perth (09) Local (380 3272).
                                                             _--_|\       N
Department of Psychology                                    /      \    W + E
University of Western Australia.      Perth [32S, 116E]-->  *_.--._/      S
Nedlands, 6009.  PERTH, W.A.                                      v

Joy is a Jaguar XJ6 with a flat battery, a blown oil seal and an unsympathetic
wife, 9km outside of a small remote town, 3:15am on a cold wet winters morning.
-------------------------------------------------------------------------------

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

Date: Wed, 16 Dec 92 13:31:05 EST
From: digests (Email Digest Server)
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    Yo,

    The following brief message to space digest contains the
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no point in everyone reading it.  But please read and act on it *soon*!

                Virtually yours,

                Incoming Mail Daemon
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From: Mark Budd <[e-mail]>
Subject: Request for "Space News" info
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Hello!

  I have a friend who has a subscription to a weekly newspaper called
Defense News.  He has told me that the same publishers produce a paper
called Space News.  Could anyone who has heard of this please pass on
any opinions as to what it's like?  Preferably people who don't work for
the paper :-).  E-mail responses would be preferred.

Thanks,
    Mark

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

End of Space Digest Volume 15 : Issue 566
------------------------------