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Date: Sun, 31 Mar 91 01:39:09 -0500 (EST)
Subject: SPACE Digest V13 #330
SPACE Digest Volume 13 : Issue 330
Today's Topics:
MAJOR GEOMAGNETIC STORM UPDATE #1 - 27 MARCH - STORM ENDED
Re: Linear launchers on Earth
RE: EM Launchers and G loads
Shuttle Velocity
Commercial Space news (4 of 12)
Re: "Follies"
Commercial Space news (12 of 12)
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Subject: MAJOR GEOMAGNETIC STORM UPDATE #1 - 27 MARCH - STORM ENDED
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/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
GEOMAGNETIC STORM UPDATE
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
23:30 UT, 27 March
-------------
STORM UPDATE INFORMATION:
The update scheduled for 06:00 UT was not posted due to local computer
problems. We apologize for the loss of that update.
The geomagnetic and auroral storm has ENDED. A shock from the recent
major flaring has not yet been observed, and the probability for observing
another shock is falling as time passes. Presently, an increase in
geomagnetic activity is not expected. A return to more normal conditions
will continue.
HF and VHF conditions are quickly returning to normal over middle and
low latitudes. DX is now possible, following the strong degradations which
occurred earlier this week. Conditions, particularly over the more
northerly latitudes, will continue to be somewhat unstable, although
significant improvements are expected. High latitudes and polar latitudes
will continue to experience some degradation in signal quality due to
enduring proton activity. However, the strong PCA event is pretty well
over now. Only very slight absorption is being measured (less than 0.5 dB
in the night-sectors).
Thanks to all of you who sent in reports during this major event. A
summary of this event will be compiled and posted for general viewing over
the next few weeks.
The following alerts have been CANCELLED:
- MAJOR GEOMAGNETIC STORM ALERT
- GEOMAGNETICALLY INDUCED CURRENT (GIC) ALERT
- LOW LATITUDE AURORAL ACTIVITY ALERT
The following alerts remain IN PROGRESS:
- SATELLITE PROTON EVENT ALERT
- POLAR CAP ABSORPTION EVENT ALERT
- POLAR AND HIGH LATITUDE RADIO SIGNAL BLACKOUT ALERT
The following warnings are IN PROGRESS:
- POTENTIAL MAJOR SOLAR FLARE WARNING
- POTENTIAL PROTON FLARE WARNING
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
------------------------------
Date: Wed, 27 Mar 91 22:12:12 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Disclaimer: Opinions expressed are those of the sender
and do not reflect NIST policy or agreement.
Subject: Re: Linear launchers on Earth
>From: henry@zoo.toronto.edu (Henry Spencer)
>Subject: Re: EM Launchers and G loads
>Date: 27 Mar 91 17:44:31 GMT
>Organization: U of Toronto Zoology
>In article <Added.QbwATBK00UkT8ICk8N@andrew.cmu.edu> RANCK@VTVM1.CC.VT.EDU ("Wm. L. Ranck") writes:
>>...something running along the desert and then gradually curved up the side
>>of a mountain...
>Building that last curve will be a civil engineering project to end all
>civil engineering projects -- a large mass moving at 7-8 km/s tries
>very hard to keep on moving in a straight line. Assume a bend radius
>of 10km, which is pretty generous, and the side force at 7km/s is a
>mere 500G. Wasn't this supposed to be a low-acceleration device... :-)
It would be a very *big* project, but the magnitude of the force shouldn't
be all that unmanageable. (I agree it wouldn't be worth it.)
>What you want, actually, is to build a rather shorter catapult along
>a long, high mountain ridge sloping up to the east. Then you can make it
>straight and still shoot into relatively thin air. You don't actually
>need the upward angle -- the Earth's curvature will take it out from
>under your payload quickly enough -- but getting out of the atmosphere
>is important.
>"[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology
>believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry
OK, here's a new idea for a linear launcher that I bet isn't even among
Eugene's 9999 (that have already been thought of):
First, build the linear launcher of your choice, but make it completely
level.
Second, get several hundred million tons of steel, and build an artificial
mountain along the trajectory of the launcher. The slope of the side facing
the launcher should have a slope of something less than 45 degrees (an
adjustable slope would be nice), and the outer 10 or 20 meters should be made
of tempered spring steel.
Now, when you fire your launcher, the projectile shoots out of the muzzle,
and -BLAMMO!- ricochets off the slope of the steel mountain, flying off
into space at a nice, steep, atmosphere-avoiding trajectory.
Of course, this won't do anything to reduce G-loading (the forces will be
rather high at the instant of impact), and you will probably have to repair
or replace the mountain surface periodically, but think of the simplification
of the engineering! :-) :-) :-)
Another problem for linear launchers in general: I don't have the numbers
handy, but I believe the shock wave of the projectile passing through the
atmosphere would generally be great enough to kill everything for several
miles around (and it could be heard for hundreds of miles). Fortunately,
there are regions in the Andes that are little more than bare soil for hundreds of miles. So pick out whatever western South American country we have the
least bad relations with at the moment, and start negotiating. :-)
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Wed, 27 Mar 91 11:06:37 EST
From: "Wm. L. Ranck" <RANCK@VTVM1.CC.VT.EDU>
Subject: RE: EM Launchers and G loads
Hello folks,
I have been reading the Space Digest archives for a while and noticed
an ongoing discussion of the problems/potentials of EM or 'rail gun'
launchers. Since I first saw some reports on MIT experiments with
this technology I have always thought it would be a good method for
launching space vehicles.
Now, my question is this. Why does everyone assume that you want
maximum acceleration from the system in the shortest possible distance.
I can see that it make the system cheaper to build and the energy
efficiency is probably better; but why not build a long rail system
that accelerates the payload at 2 or 3G over many miles. Imagine
something running along the desert and then gradually curved up the side
of a mountain. At the top end you still need a booster of some sort
to circularize your orbit, but it could be a heck of a lot smaller than
the monsters we launch now.
Is there some obvious problem with this that I'm missing? Is it
just tunnel vision that makes people think of maximum acceleration from
an EM launcher? Of course for smaller hardened payloads a higher
rate of acceleration could be provided by the very same launcher.
This is probably a novice FAQ, but I couldn't find anything in the
archives.
Bill Ranck
------------------------------
Date: Wed, 27 Mar 91 15:12:26 CST
From: JD <S105646@UMRVMA.UMR.EDU>
Subject: Shuttle Velocity
X-Acknowledge-To: <S105646@UMRVMA>
I was in an discussion with a friend of mine and we got talking about the
Shuttle and we were discussing the speeds that the shuttle must achieve. And I
am one for trivia, so I remembered I fact I thought I had heard--that when the
shuttle clears the tower it is going over 100 mph. He didn't believe me and
said that would be to fast and it would create to many G's for human to take.
Could someone out there please back me up on this or correct me. And if
someone knows could you please send me some numbers, such as velocity when
clear of the tower and G-forces acting on the shuttle. I know this is trivial
but we are both interested to find out if this is correct. Thanks for the
