HDTenEightyP/NetNews huggingface dataset:
From: Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald)
Newsgroups: sci.space
Subject: Re: Home made rockets
Date: 19 Aug 92 01:52:18 GMT
 <BBeDPB4w165w@iowegia.uucp>
Organization: Dartmouth College, Hanover, NH

In article <BBeDPB4w165w@iowegia.uucp>
quest@iowegia.uucp (Steve J. Quest) writes:

>         I think the point that should be made is "maybe the guy 
> who wants to build engines IS more intelligent and safety 
> conscious than you have given him credit for"?  All you really 
> should have said was "do you know what you are doing" and if they 
> respond with "I think so" then help them out.  That is my two 
> cents worth..........sq

I really doubt it. First, that he even brings up the topic of a
KNO3/sugar mixture, melted and spooned into a rocket casing - just that
he can bring up this particular specification at all - shows he has no
idea just how dangerous it is, that there are much safer and more
effective ways of making rockets, and most seriously, that since he
didn't know this, he didn't do his homework FIRST before beginning work
with obviously hazardous materials. (It's a rocket, for crying out
loud!)

Second, the spelling in both his posts suggests a lack of attention to
detail that, in making homemade rockets, can lead to that nasty
surprise. He didn't even get the name "Estes" right, writing it "Stes."
The capitalization makes this an unlikely typo, too.

Along this thread, the argument "no activity is 100% safe, and the
desire for it is what's wrong with contemporary American society," has
been raised several times. It's fallacious and irrelevant. Home
explosives manufacture isn't even remotely CLOSE to 100% safe. True,
while it is possible to die from an infected paper cut from stamp
collecting, it's considerably less likely than blowing off a hand from
improperly packing a rocket casing, due to ignorance of how to do it
properly. Once body parts are blown off, they tend to stay off.

I e-mailed the original poster the list of suppliers from
rec.models.rockets, and told him I wished he could legally obtain at
least some of those products in his country, some being from Canada and
the UK. I also told him I wished he'd stick with models, until he
learned more about what he's doing, so I've had more than enough of
this thread. This is my $1.69 worth.

P.S. I have extreme difficulty believing your claim of building a
rocket with 40 kg of propellant for a few hundred dollars as a
teenager. ThatUs a veritable anti-aircraft weapon! Furthermore, I think
your assertion that it's not science unless you break the safety rules
is unconscionably irresponsible: look what happened when some real
rocket scientists broke the safety rules with Challenger.
From: Mark Goodman <mwgoodman@igc.apc.org>
Newsgroups: sci.space
Date: 18 Aug 92 07:20 PDT
Subject: Re: Early Warning of missiles and meteo
Nf-ID: #R:ucru2.ucr.edu:6202:cdp:1469100010:000:2350
Nf-From: cdp.UUCP!mwgoodman    Aug 18 07:20:00 1992


To:    sci.space From:  Mark Goodman (mwgoodman@igc.org) Re:
Meteoroid Detection Date:  18 Aug 1992

The question was asked whether U.S. ballistic missile early
warning systems could detect 1 meter meteoroids.  I think the
answer is yes, but it depends.

U.S. early warning radars operate by scanning across the horizon
for missiles or components (most likely upper stages and buses,
which send MIRVs on their independent trajectories) as they rise
above the horizon, at a distance of several thousand kilometers.
These objects have radar cross-sections of up to a few square
meters.  At that distance, they spend several tens of seconds in
the radar's fan, and the radar has several opportunities to view
them.  By adding the signals from separate radar sweeps, the radar
can achieve the high signal-to-noise ratio needed to detect
missile launches with high confidence and without significant risk
of false alarms.

The return signal from the radar scales as R^-3.  (R^-2 each for
difraction of the direct and return signals, and an extra R to
reflect the fact that objects farther away more at a slower
angular rate and spend more time in the radar fan, allowing a
larger integrated signal.

Meteoroids also travel faster than ballistic missiles -- tens of
km/sec compared to up to 7 for missiles, at least until they get
vey low in the atmosphere and are below the radar fan -- so
theradar won't have as much time to look.  The United States has a
PAVE PAWS radar in Georgia for warning of SLBM attack, which I
think had a good chance of seeing a meteoroid off Daytona Beach.

Two points of potential confusion.  It is said that radars can
objects the size of a grapefruit (or perhaps smaller) in orbit.
That is only when the objects pass nearly overhead in low orbits,
a few hundred kilometers away.  This also allows longer times for
tracking.

Also, over-the-horizon radars are irrelevant to this discussion.
They do not have anything like the sensitivity required to see a
meteoroid against the backscatter of the Earth's surface.

+-----------------------------+-----------------------------+
|       Mark W. Goodman       | What a terrible thing it is |
| mwgoodman@igc.org -- econet | to lose your mind.          |
| goodman@ksgbbs.harvard.edu  |                             |
+-----------------------------+-----------------------------+

Newsgroups: sci.space
From: tjn32113@uxa.cso.uiuc.edu (Thomas J. Nugent)
Subject: Re: Beanstalks in Nevada Sky (was Re: Tethers)
Organization: University of Illinois at Urbana
Date: Wed, 12 Aug 1992 22:14:02 GMT

higgins@fnalb.fnal.gov (Bill Higgins-- Beam Jockey) writes:

>In article <63811@cup.portal.com>, Eric_S_Klien@cup.portal.com writes:
>> Would it be possible to put something in near orbit over Nevada and 
>> attach tethers to it so that people could reach the object via 
>> elevators?  I know it wouldn't be easy, but is there a way to pull 
>> this off?

>Hmm. Interesting question.  To first order:  No, it's impossible, for two
>reasons.   

>Let's examine your question again.

>> Would it be possible to put something in near orbit over Nevada and 
>> attach tethers to it 

>You could hang over Nevada in a non-Keplerian orbit, that is, if you
>were willing to thrust continuously.  You can hire a helicopter pilot
>to do this until her fuel runs low.

>Bob Forward has proposed using high-performance solar sails to put
>payloads into such orbits.  I think there's a pop discussion of this
>in his book *Future Magic*, and more technical stuff in various AIAA
>papers.  There's no obstacle in principle to this that I know of, but 
>the technology required (really light, really large, highly reflective
>sails) is at least a couple of decades away.

>If the altitude were low enough, the strength requirements on your
>tether would go down, and it might really be buildable (given
>staggering technology).

One thing you forgot, Bill:  Space fountains.  Accelerate ferromagnetic(?)
"hula hoops" electromagnetically, aiming them nearly straight up.  Then
decelerate them electromagnetically, transferring both momentum and 
electricity to the decelerator.  This is itself a huge ring, sort of.  
Imagine a hollowed out cylinder, with two much smaller cylinders cut
out of the remaining material, opposite each other.  The hoops go up thru
one side, where they are decelerated, giving an upward momentum boost to
the huge cylinder, and with the power generated from this, they are
accelerated downward on the other side (when they reached the top of the
fountain, they were turned back down towards Earth), thus balancing the
momentum transfer on both sides of the cylinder.  STack a bunch of these,
and voila! a space fountain.  This was also studied by Forward, along with
many others.  As far as I can remember, it doesn't require any material
advances.  And the neat thing is, by working it properly, you can have
a geosynchronous satellite above just about any point on Earth, up to any
height.  The power requirements are very large, of course (I don't remember
exactly), but within reason.  You can then also ride this up to space in
a variety of fashions. 

"Far better it is to dare mighty things, to win glorious triumphs, even
though checkered with failures, than to rank with those poor spirits who
neither enjoy nor suffer much, because they live in the gray twilight that
knows not victory nor defeat."
		- Theodore Roosevelt 
-- 
"To be average scares the hell out of me." -- Anonymous
Tom Nugent		e-mail: tjn32113@uxa.cso.uiuc.edu
From: ralph.buttigieg@f635.n713.z3.fido.zeta.org.au (Ralph Buttigieg)
Newsgroups: sci.space
Subject: light pollution
Date: 7 Aug 92 18:17:06 GMT
Organization: Fidonet. Gate admin is fido@socs.uts.edu.au

Original to: Gay_Canough@Gw.Isu92.Ac.Jp
Hi Gay,

 g> powersats will have to be built before we can even 
 g> begin to think of building
 g> something 50 sq.km in size. The space power community 
 g> now realizes that trying
 g> to design such a large thing before doing a lot of 
 g> smaller powersats is purely
 g> ridiculous. Still, we hope that some day, we will be able to build large
 g> systems to keep Earth well supplied with power. Issues 
 g> such as light pollution
 g> (which I believe is a very legitimate environmental concern), should be
 g> addressed early along with other environmental problems 
 g> such as space debris,
 g> effects of power beaming and effects of launching. 

 For what its worth I'll like to add my two cents worth.

 1) Perhaps the best near term bet would be to develop Space Power Relay
 capability rather then actual power production. A world wide
 electricity grid would open up new energy sources and make more
 efficiant use of current ones.

 2) Maybe we can take a leaf from current work on small LEO comsats.
 I have read that enough satellites orbiting in two belts at plus
 or minus 45 deg to the ecliptic at 2900 mile altidude can service
 any point on Earth.
 Perhaps instead of building huge single satellites, thousands of
 smaller units be used, maybe working together in clusters.
 Being closer to Earth, the transmitter can be smaller. I'm imagining
 something about 20 tonne mass that could deliver say, 5 megawatts
 power. Prototypes could be launched with current rocketry. Mass
 produced production models may be able to be launched by a Space gun.

 Comments from readers appreciated.
 ta
 Ralph

--- Maximus 2.01wb
 * Origin: Vulcan's World-Sydney Australia 02 635-1204 (3:713/635)
From: quest@iowegia.uucp (Steve J. Quest)
Newsgroups: sci.space
Subject: Re: Home made rockets
Date: 16 Aug 92 06:34:13 GMT
Organization: Iowegia Waffle BBS, Clive IA USA, +1 515 226 2156

gary@ke4zv.uucp (Gary Coffman) writes:

> The book "Rocketry for Amateurs" has range designs, rocket designs,
> fuel recipies, and intensive safety precaution information for the
> amateur rocketeer. You don't have to limit yourself to Estes models.
> If you don't take the proper precautions, you're as dangerous as
> someone randomly firing a high power rifle in a shopping mall. In
> *that* case, you deserve to be arrested. Carmel candy rocket fuel
> is *extremely* dangerous to handle. Unless you have remote controlled
> fuel processing equipment, I'd recomend that you change to zinc/sulphur
> or some other mixture that doesn't require melting the fuel. Forget
> about black powder. Another name for a black powder rocket is *pipe
> bomb*.
> 

Gary,

        Black powder is the fuel that Estes uses- so you can't say 
that it is all THAT dangerous!  All one has to remember is that 
black powder is an explosive when finely divided.  Therefore, to 
make a rocket fuel, it has to be compressed very tightly.  A 
method I have used was to rig up a 1 ton bottle jack in a steel 
frame to compress fuels  I could reload Estes engines about 3 
times using this method.  Of course, this was well before I began 
using castable fuels, which have all the inherent dangers that 
have been previously mentioned.  As when making candy, a 
thermometer is "very handy" when making solid cast fuels.....sq
Newsgroups: sci.space
From: Mark Goodman <mwgoodman@igc.org>
Newsgroups: sci.space
Date: 12 Aug 92 06:55 PDT
Subject: Re: Energya and Freedom and Soyuz ACRV 
Nf-ID: #R:168mm3INNak7@agate.berkeley.edu:216680648:cdp:1469100008:000:2248
Nf-From: cdp.UUCP!mwgoodman    Aug 12 06:55:00 1992


Quoting Allen Sherzer:
 
>Come now Mr. DeLuca, your grasping as straws. When fabrication begins
>it won't take long to build another. As to killing the project, not
>likely give the huge and lasing political support it has received.
 
I am not aware of any huge and lasting support.  The House votes have
been about 230-180, far from 2-1, and then only because the aerospace
industry has already received such a big hit from DoD cuts.  There is
tremendous opposition to the space station, which is based on the
essential question: what good is it?  What benefits does it offer the
average taxpayer in return for its $1000/taxpayer cost (order of
magnitude)?  That's a question I certainly can't answer.
 
>First of all, even if I agreed with that, so what? Just because somebody
>else will waste money doesn't give us any right to waste. As a taxpayer,
>I am rather pissed that NASA wastes so much; I'm also pissed about all the
>other waste. All this attitude does is help keep space expensive and prevent
>private efforts from taking off.
 
This is, of course, the reason reason Allen is basically correct, in
spite of his often "imaginative" arguments.  As a taxpayer, I cannot
support the Space Station unless NASA does everything it can to reduce
its costs.  That includes using former Soviet (let's not say CIS --
the Commonwealth of Independent States will soon be a memory) technology
where feasible.  Frankly, I haven't seen any showstoppers regarding
Energiya or Soyuz.
 
>Since these will open the space frontier and produce far more tax income,
>it seems a good idea.
 
Allen, if you are refering to the Space Station, a Moon Base, or planetary
exploration, my reaction is: Come on, give me a break.  If you are
refering to investments in near-term space technology (improved ELVs,
perhaps SSTO, improved automation and remote control, lightsats, etc.)
and R&D on more distant prospects (NASP, etc.), I agree.  Which is it?
 
+-----------------------------+-----------------------------+
|       Mark W. Goodman       | What a terrible thing it is |
| mwgoodman@igc.org -- econet | to lose your mind.          |
| goodman@ksgbbs.harvard.edu  |                             |
+-----------------------------+-----------------------------+
From: thierry@curlie.UUCP (Thierry Lach   )
Newsgroups: sci.space
Subject: Re: Asteroid report
Date: Fri, 21 Aug 92 23:34:00 EDT
Organization: Not An Organization

forrie@morwyn.uucp (Forrie Aldrich) writes:

> Recently, and associate mentioned there was a report of a rather large
> asteroid (or some object) approaching or within our solar system, and
> with a trajectory currently in our direction.  And that radio signals
> have been transmitted from said object.
> 
> This does sound a little out-of-the-ordinary, can someone confirm or
> deny this? (for those familar with Arthur C. Clark, the above reference
> makes me have visions of RAMA heading our way... ::wince:: ;)
> 
> Thank you.
> 
> -- 
> 	   -----------	      Forrest Aldrich	      -----------
> 	   -------     morwyn!forrie@unhtel.unh.edu	  -------
> 	   ----						     ----
> 	   --	     VISION GRAPHICS --	Dover, NH - USA	       --
> 	   ------------------------------------------------------

or maybe Niven and Pournelle (_Footfall_) ?
Newsgroups: sci.space
From: forrie@morwyn.uucp (Forrie Aldrich)
Subject: Asteroid report
Organization: Vision Graphics
              Dover NH
              USA
Date: Fri, 21 Aug 1992 00:17:37 GMT

Recently, and associate mentioned there was a report of a rather large
asteroid (or some object) approaching or within our solar system, and
with a trajectory currently in our direction.  And that radio signals
have been transmitted from said object.

This does sound a little out-of-the-ordinary, can someone confirm or
deny this? (for those familar with Arthur C. Clark, the above reference
makes me have visions of RAMA heading our way... ::wince:: ;)

Thank you.

-- 
	   -----------	      Forrest Aldrich	      -----------
	   -------     morwyn!forrie@unhtel.unh.edu	  -------
	   ----						     ----
	   --	     VISION GRAPHICS --	Dover, NH - USA	       --
	   ------------------------------------------------------
Newsgroups: sci.optics
From: swami@chtm.eece.unm.edu (Swami srinivasan)
Subject: Re: construction of an isolation table
Date: Fri, 14 Aug 92 23:29:40 GMT
Organization: University of New Mexico, Albuquerque
Distribution: world,local

In article <12550@ecs.soton.ac.uk> hnr@ecs.soton.ac.uk (Harvey Rutt) writes:

>In <1992Aug13.152035@ece.arizona.edu> mikey@ece.arizona.edu (Michael Gribbons) writes:
>>can anyone give me some references for the construction of an isolation
>>table. the application is holography and the main problem is vibration
>>from passing trains. email or post responses.
>>mike

>The 'standard' cheap simple solution is a suitable flat heavy plate
>(steel, or a 'gravestone' from your local monumental mason, or
>whatever suppliers of gravestones are called in the USA) supported on
>three partly inflated car inner tubes.
>Harvey Rutt
>Southampton University UK

	There's one problem there! In the US, car tyres do not have
inner tubes.... 

 In Madras, India, we did holography next to a Mechanical Engg.
workshop. The table-top was a single granite block, 8' x 4' x 8" or
thereabouts. It was never meant to be a gravestone, though! Holes
were drilled by the same masonry firm that supplied it. 

	The whole block was supported by something resembling a 
coir mattress, 5' wide. Coir is the tough fiber that encloses
the coconut inside the fruit. It is widely used, and often used 		
to make mattresses. It's inexpensive, and was good enough for our 
purpose.

	Of course, this doesn't help the original poster in any way,
but it is interesting how people find ways to do science without 
mega-buck facilities. 

							swami

====================================================================
swaminathan srinivasan
center for high tech materials		swami@chtm.eece.unm.edu
university of new mexico,
albuquerque, nm 87131, usa
====================================================================

Newsgroups: sci.optics
From: ngrjn@milton.u.washington.edu (V Nagarajan)
Subject: What is a (multiple) quantum well reflector...
Organization: University of Washington, Seattle
Date: Tue, 18 Aug 1992 23:58:28 GMT

	that is used as an end mirror to passively mode lock a solid-state
	laser? Explanations, expositions, tutorials, references welcome.
	Thanks.
							- Nagarajan


Newsgroups: sci.optics
From: schuetz@kalium.physik.tu-berlin.de (Marcus Schuetz)
Subject: Re: construction of an isolation table
Organization: ZRZ/TU-Berlin
Distribution: world,local
Date: Fri, 14 Aug 1992 14:24:38 GMT

In article <1992Aug13.152035@ece.arizona.edu> mikey@ece.arizona.edu (Michael  
Gribbons) writes:
> 
> can anyone give me some references for the construction of an isolation
> table. the application is holography and the main problem is vibration
> from passing trains. email or post responses.
> 
> thank you very much,
> mike

We construct our isolation tables the following way :
 - polystyrene blocks as basis
 - rubber foam ( thickness 15 cm ; no, it won't get compressed )
 - a wodden box filled with 3 - 5 cm of quartz sand
 - a granite "grave stone"  10 cm thick

To mount the optical components we put a magnetic stainless steel plate
on top and fixed it with double-sided adhesive tape ( permanent! ). The 
components are fixed on magnetic holders. The drawbacks are the costs 
for the steel plate and the magnetic holders. 

You can let the stonemason bore holes into the granite ( e.g. every 5 cm ) 
and put threads into them. It's cheaper if you do it yourself, but it's 
hard work ( ca. 400 holes on a 1 * 1 m table ) and that is the drawback of 
this method.

Extra disclaimer: it should work fine, but of course i give no guarantees


Marcus

"He's dead, Jim!" Leonard "Bones" McCoy

--
==============================================================================
Marcus Schuetz                     |  DISCLAIMER: I don't speak for Starfleet
schuetz@kalium.physik.tu-berlin.de |              Command, my mother or anyone
TU Berlin, Institute for           |              else. These thoughts are 
Ray- and Nuclear Physics           |              exclusively my own.
==============================================================================
From: carter@cemvax.cem.msu.edu (Tom Carter)
Newsgroups: sci.optics
Subject: re: UV measurement device wanted
Date: 12 Aug 92 13:15:17 GMT
Organization: Michigan State University, East Lansing Michigan

In article <petek.713605079@vipunen.hut.fi> petek@vipunen.hut.fi (Petri 'Pete' Karha) writes:
>Hello.
>I'm trying to build a calibration system for UV detectors as my masters
>degree. To this I would need an accurate measurement device for UV
>range, a Thermal or pyroelectrical detector or something like that. It
>should also include the visible light range so that it could be calibrated
>with a laser. 
>
>The only company I know producing these is Laser Precision but to get
>the idea about whats available I would need some pointers to other
>companies who might have them. So please, if you know any, let me know.
>Thanks.
>
>-- 
>s32852b@puukko.hut.fi ! Petri 'Pete' Karha     !  Copyrights (C) by
>petek@otax.tky.hut.fi ! Kirstinharju 11 L 198  !      Pete ltd
>petek@vipunen.hut.fi  ! SF-02760 Espoo         !  Patents pending.
>Tel: +358-0-8053655   ! FINLAND the FUNLAND    ! 

Here are a couple:

Newport Corp.
1791 Deere Ave
Irvine, CA 92714
800 22206440
(714) 963 2015
(Europe: Newport GMBH 06151-1540)

Scientech
5649 Arapahoe Avenue
Boulder, CO 80303
800 525 0522
303 444 1361

Ophir Optronics
21 Main Street
North Reading, MA  01864
508 664 1176
(Scandinavia: Lambda (08) 662 0610)

Molectron Detector, Inc.
7470 SW Bridgeport Road
Portland, OR  97224
800 366 4340
503 620 9069

I hope these help.

============================================================================
|         Tom Carter                    |     carter@cemvax.cem.msu.edu    |
|   Michigan State University           |     carter@msucem.bitnet         |
|     Chemistry Department              |                                  |
============================================================================
Newsgroups: sci.optics
From: carl@aoa.aoa.utc.com (Carl Witthoft)
Subject: Re: Calibration of a PMT
Organization: Adaptive Optics Associates
Date: Thu, 13 Aug 1992 16:57:44 GMT

In article <1992Aug12.201617.17959@EE.Stanford.EDU> siegman@EE.Stanford.EDU (Anthony E. Siegman) writes:
>
>The gain (i.e., multiplication) of a PMT is _extremely_ sensitive to
>the applied voltage (maybe to the eighth power for an 8-anode PMT).
>And, the absolute sensitivity of the photocathode is _extremely_
>sensitive to age, processing and sample to sample variations,
>poisoning and aging, temperature, history, and everything else (the
>stated sensitivity curves are only rough indications of any tube's
>actual sensitivity).  And both cathode sensivity and gain are likely
>to vary quite widely from spot to spot on the cathode surface.
>
x
Very true.  There are some tricks you can use to make the PMT
"calibration" more stable.
1) use a lens to diffuse your sample over the entire face of the
PMT.  This reduces spatial nonuniformity effects (of the cathode).
2) Make sure you have a vary stable, even a feedback-controlled,
voltage source for the PMT.
3) Keep in mind that photocathodes tend to "bleach" even with
no voltage applied if there's a lot of light around.  Leave the PMT
 on, in the dark for up to 2 hours or so before starting to take data.
This will maximize sensitivity and reduce temporal variation in 
responsivity.  That is, if you start right out taking data, as the
cathode unbleaches in the dark, (assuming you have a very small
signal input), the responsivity will rise and your data will be biased.
By and large PMTs are rotten.
oh, and
4) do AC measurements whenever possible, e.g. chop your source.


-- 
Bobby Newmark, aka  Carl Witthoft @ Adaptive Optics Associates
aoa!carl@bbn.com  carl@aoa.utc.com
54 CambridgePark Drive, Cambridge,MA 02140 617-864-0201
**Just say NO to HMOs**