Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_4/V13_411.TXT

Internet Message Format | 1991-06-28 | 18KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/Yc2chVS00WBwEOq05x>;
          Tue, 16 Apr 91 01:28:01 -0400 (EDT)
Message-ID: <kc2chES00WBwMOoE4=@andrew.cmu.edu>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Tue, 16 Apr 91 01:27:46 -0400 (EDT)
Subject: SPACE Digest V13 #411

SPACE Digest                                     Volume 13 : Issue 411

Today's Topics:
               Light Pollution
      test Einstein's theories during next total solar eclipses
                lawsuits etc.
             Re: Laser launchers
        Re: comsat cancellations and lawsuits
        Re: Teflon (Was Re: Space technology)
               geology address
           Re: Advancing Launch Technology
              RE: SPACE Digest V13 #405
            SPACE Digest V13 #405
              Orbital Mechanics formulas

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: Sun, 14 Apr 91 23:57:46 PDT
From: fermat![e-mail] (Richard Schroeppel)
Subject: Light Pollution

  John McCarthy suggested (facetiously?) one way for astronomers to
deal with light pollution:  Arrange for all our lighting have a 10%
duty cycle, with 1 millisecond on, and 9 msec off.  The lights would
all be synchronized.  An astronomer would put a simple rotating
shutter in his telescope's light path, and his telescope would see a
dark sky.
  This is hypothetical, but it brings up an interesting point:
any light connected to the power grid is already cycling at 120 Hz.
Has anyone looked into background subtraction?  Have two CCDs, and
switch the light path at 120 Hz.  One CCD gets the bright part of
the cycle, and one the dim half.  Some linear combination cancels
out the city, leaving the sky.  Not a panacea, but it could give the
telescope a couple of extra magnitudes of sensitivity.

Rich Schroeppel                                       [e-mail]

     Better to shoot out a single street light,
     than to curse the light pollution.

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

Date: 15 Apr 91 21:28:24 GMT
From: comp.vuw.ac.nz!matai.vuw.ac.nz![e-mail]
Subject: test Einstein's theories during next total solar eclipses

With all this talk of observing total solar eclipses, I hope some
people are planning to do some real science.  For instance, why
not record images (photographic film or CCDs) of the star positions
near the sun during totality and compare to the same region at night
(ie not during the eclipse) to look for shifts in the stars
apparent positions and check Einstein's predicted angular shifts
due to space curvature around the Sun.

This is not just a 'worthless' repeat of a previous successful
experiment as an astronomy friend of mine told me that a later
independant analysis of the original observations to test this
theory revealed that the uncertainties in the observations were
as large as the observed shifts themselves.  With modern equipment,
we should be able to do better than that now (no slur is intended
about the original observers).

So now is your chance (amateur or professional) to disprove or
confirm the theories of one of the great genuises of our time.
--
+------------------------------------------------------------------+
| I'm a toxophilite,         | Murray Forbes,                      |
| so what's your problem?    | Physics Department,                 |
|----------------------------| Victoria University of Wellington,  |
| standard disclaimer :      | New Zealand.                        |
| all opinions here are mine | [e-mail]            |
+------------------------------------------------------------------+

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

Date: 15 Apr 91 16:32:55 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!rpi!uupsi!pbs.org![e-mail]
Subject: lawsuits etc.


In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (Charles Frank Radley) writes:
>>  NASA never guaranteed to launch anything.
>>The language in the standard Launch Services Agreement
>>states NASA will use "their best endeavours", which
>>means no warranty etc.
>
> Still sounds like grounds for a lawsuit to me.  *What* "best endeavours"?
> More like "we'll launch it if it's convenient, but at the first sign of
> trouble, forget it".
> --
Let us not forget the CHALLENGER disaster was not some minor disturbance.  In
other words, it took something of MAJOR PROPORTIONS to disrupt NASA's launch
capability.  Implying that NASA will bail out of launch commitments at the
"first sign of trouble" is both an oversimplification and downright insulting.
And to get this thread back on its original heading, corporate greed did play a
part in setting up this situation.  Affraid of loosing money Morton Thiokol
kept NASA managers in the dark by withholding information that should have been
passed along.  Alerted to potential trouble areas earlier, there may have been
a diferent reaction to that engineer's recommendation not to launch due to
extreme cold.  Morton Thiokol should also have stood behind its engineer's
judgement, but instead they put on the management hat and took off the
engineer's hat etc.  With a little bit more common sense and a more open
sharing of engineering concerns, the shuttle could probably have continued
flying, just not on extremely cold days.  But how often do days with weather
like Jan. 28, 1986 come along in that part of Florida?  Perhaps Morton Thiokol
should be co-defendants in any lawsuits from Hughes, or anyone else, about
launch schedule disruptions.
1986

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

Date: 15 Apr 91 17:47:37 GMT
From: wuarchive!cs.utexas.edu!titan![e-mail]  (Donald Heskett)
Subject: Re: Laser launchers

Nick Szabo says:

> [buncha stuff deleted]... You also ignore gas gun, tethers, and several
> other options...[bunch more stuff deleted]

Could you explain what you mean by "tethers"? (Sorry if it has been
hashed and re-hashed, but usually I don't have time to follow this
group as well as I'd like.)

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

Date: 15 Apr 91 16:41:17 GMT
From: mintaka!think.com!zaphod.mps.ohio-state.edu!rpi!uupsi!pbs.org![e-mail]
Subject: Re: comsat cancellations and lawsuits

In article <hmdgf#[e-mail]>, [e-mail] (Michael V. Kent) writes:
> In article <[e-mail]> [e-mail] writes:
>>In article <[e-mail]>, [e-mail] (Fraering Philip) writes:
>>>
>>> This is really twisted, when you think about it: "Based on past
>>> wrongs by 'aerospace companies' which may or may not include Hughes
>> (they do include Hughes)
>
> Do you have anything particular in mind, or is this a blind hatred?
>
 Faulty avionics in an Army helicopter program that could have killed some
flight crews.

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

Date: 15 Apr 91 14:17:39 GMT
From: eru!hagbard!sunic!mcsun!hp4nl!star.cs.vu.nl!balaena![e-mail]  (Thomas Tonino)
Subject: Re: Teflon (Was Re: Space technology)

In article <[e-mail]> [e-mail] (Nikhil Ranjan Joshi) writes:
>In article <[e-mail]> [e-mail] (Marvin Minsky) writes:
>>In article <[e-mail]>
>>[e-mail] writes:
>>>The trick in making non-stick frying pans is to get
>>>the pan to stick to Teflon as *nothing* sticks to Teflon!!
>>
>>O.K., I give up.  What's the trick.
>
>
>small mushroom-shaped bumps on the surface (though very flat of

It is possible to glue to teflon using a kind of titanium ester compound.
Sounds rather nasty and I don't know if it is any use sticking teflon
to things.

Besides there also are sprays which leave solid teflon, so maybe it does
stick after all, only not so well...

Thomas

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

Date: Mon, 15 Apr 1991 11:38 EST
From: [e-mail]
Subject: geology address


What is the address of the GEOLOGY newsgroup mentioned recently?   Thanks.

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

Date: 14 Apr 91 17:05:48 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Advancing Launch Technology

In article <[e-mail]>, [e-mail] (Nick Szabo) writes:

>You repeat this as if it was an argument in your favor.  The fact that
>chemical rockets have such long design cycles is one of their problems.
>If we want to wait around until 2500  to colonize space (no exageration
>-- this is based on the curve of chemical rocket launch costs since 1960),
>and assume no other new technology between now and then, what you say might
>be reasonable.

You are asserting this? 2500? Are you smoking something? GAG.


     Signature envy: quality of some people to put 24+ lines in their .sigs
  -- >                  [e-mail]                        < --

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

Date: Mon, 15 Apr 91 12:33 GMT
From: AMON <[e-mail]>
Subject: RE: SPACE Digest V13 #405


Vacuum breathers:

The issue of survival of an unprotected human in a vacuum is an interesting one.
It is also not simple. First, explosive decompression is almost certainly
instantly fatal. As evidence, look into the records on the breakup of Comet
airliners at high altitude in the 50's. It was known that the airliner
airliners at high altitude in the 50's. It was known that the airliner cracked open
at high altititude because of the decompression effects on the bodies. Shredded
lungs and unlarged hearts among them.

But RAPID decompression is another story. First, as with divers coming up
from a depth, the mouth must be kept open to allow the expanding air to escape.

An additional problem I would see is that the lungs would end in a fully
collapsed state, and I'm not sure this can be undone without medical
intervention.

There may have been some tests on rapid decompression on Air Force volunteers
back in the 50's or as part of the run up to Mercury. Not sure about this,
and I suspect Henry has a library near at hand to check, assuming he
hasn't posted already...

Also note that Judy Resnick and Mike Smith were still alive after the shuttle
breakup and were obviously in a decompressed state at about 40,000 feet.
There is not a whole lot of breathing air at FL400...

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

ReSent-Message-ID: <[e-mail]>
Resent-Date:  Mon, 15 Apr 91 15:50:45 EDT
Resent-From: Tommy Mac <[e-mail]>
Resent-To: [e-mail]
Date:         Sun, 14 Apr 91 01:54:52 EDT
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #405
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>

>From: unisoft!fai!sequent!crg5![e-mail]  (Nick Szabo)
>Subject: Re: SPACE Digest V13 #362

>In article <[e-mail]> space+%ANDREW.CMU.EDU@msu.e
>   u writes:
>>>[I write] $tens of billions down the tubes for
>>>chemical rocket research, money that could have been much better spent on
>>>the basic science behind superconductors, gas guns, lasers, et. al.  Well,
>>>that's all water under the bridge, but the future lies ahead -- let's
>>>do it right this time!
>>
>>1)  The basic science IS being done.

>At a very slow, vastly underfunded rate.  The budget for a _single_
>chem rocket, the Shuttle, is higher than the entire NSF budget.
>This is outrageous and unacceptable for a society that wants to go
>into space.

Are you gonna put up the cash?  The feds, who don't know what they're doing
(according to your own posts)?  Private industry?  They would have, if it
would make any $$dough.

>>Maaybe the science will come through for us.

>Science is based on work and resources, not hopes.

It's also based on goals.  If you don't 'hope' to reach your goals, why bother?

>>Point:  It has not been *proven* that chems can't lower lauch costs.

>The economic arguments I presented are pretty straightforward, and
>the real-world evidence of rocket operations to date is overwhelming.
>No, you can't 100% prove anything in this life, not even tommorrow's
>sunrise.  But the cost of working with such large amounts of fuel
>tied to such puny payloads is fairly certain.

Are you smokin' somethin'?  Your arguments aren't straightforward at all.  I
recall that at one point you had 'proven' that chems had peaked in efficiency
because of the ratio of tank size to vehicle cost.  The real world evidence,
to date, is this:  "ONLY CHEMS CAN PUT STUFF IN SPACE.  IF WE WANT TO PUT STUFF
IN SPACE, WE MUST USE CHEMICAL ROCKETS".  To wit;

>>Point:  No other system HAS PROVEN capable of the basic goal:

>I again remind you this is technology we are talking about, not a point
>of law.  No technology should ever work, by this reasoning, because
>every technology that ever worked has had to grow from being "unproven"
>to "proven".  New R&D is supposed to work on the unproven, to give us
>new technological capabilities, not just rehash the same old ones and
>call it "progress".

But we are talking about science and technology, where you don't have a jury
to mitigate your requirements for actual proof.

Since you seem to have forgotten, I will reiterate:

++++++++
Chemical rockets are the only thing that can put stuff into space.

           DOES NOT EQUAL

Chem rockets are the only thing THAT WILL EVER BE ABLE to put things in space.
++++++++

>>Point:  R&D IS BEING DONE on this stuff.

>The R&D funding for alternative launchers, _all_ of them, is less than
>1/10 the R&D for the single technology of chemical rockets.  The system
>is totally out of whack, nearly totally concentrated on pseudo-improvments
>and megaprojects with a single technology rather than searching to find
>the best technologies.  We have a vast problem in misallocation of R&D
>funds here that needs to be addressed.  One grad student at JPL working
>on MHD rockets during the summer, three engineers at Boeing working on
>magsails in their spare time, this is not even close to being sufficient
>funding.  Let's get our priorities straight or we can forget about going
>into space.

May I summarize?

It seems Nick, that you are arguing from the not-so-unique vantage point of
having a personal agenda that you think should get done for things to work out.

I conclude this for a number of reasons.  Among them are your contradictory
posts about various issues.  At one point, you seem to think that Chems are
best turned over to the private sector, while the feds should do R&D.  Now you
seem to be saying that the Fed's R&D isn't good enough.  Then, sometines, you
express the opinion that chems should just be trashed in favor of R&D on these
other technologies.
One other reason that I thnk this is your tendency to change the subject when
there is a real challenge to your views.  I.e. from $/lb to who shoud do R&D,
or perhaps from R&D costs to launch costs.

I'm quite confused, as I am sure others are.  This is most probably because you
continue to compare other's views with your 'agenda', find them lacking, then
post just why they are lacking.  I can't figure out where you're coming from.
I seriously doubt anyone else can either.

This is certainly a boost for you, as you can rip the piss out of anything that
doesn't fit your view of what 'should' be done (in spite of general agreement
on any other part of the issue), and yet you can sit secure in the knowledge
that your 'agenda' is the right one.

I would like to challenge this agenda of yours Nick.  Hold it up to light, so
we can judge it as you have.
At least tell us what you think should be done in space, since I've only been
able to get a rough idea based on what you think should NOT be done.

If you have an agenda, but fear the repercussions of anyone else seeing it, why
don't you post something about my 'ad hominem' argument, or some other dodge
tactic, so that we know where you actually stand on these issues.

Tommy Mac
18084tm@msu
Acknowledge-To: <18084TM@MSU>

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

Date: 15 Apr 91 23:07:59 GMT
From: apple.com![e-mail]  (Craig J. Keithley)
Subject: Orbital Mechanics formulas

I'm in need a of a formula that uses:
   The elapsed mission time
   The orbital elements (posted on sci.space[.shuttle])
And returns lat/lon and an altitude

I need to be able to plug in the shuttle (or satellite's) elements
and derive its position above a given spot on the earth.  I'm not
interested in orbital transfer, etc.

I've been told that I should take into account a variety of things,
including orbital decay due to air drag.  How important is it that
these things be taken into account?  If a simple equation provides
99.5% accuracy, I'll probably be happy.  This is because the shuttle's
orbit is probably changing somewhat (due to attitude adjustments),
So I don't expect 100% accuracy anyway.

While I'd prefer the equation, a book reference would be helpful
also.

Please reply via email, and I'll summarize to the net.

Thanks,

Craig Keithley
Apple Computer, Inc.
[e-mail]

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

End of SPACE Digest V13 #411
*******************