HDTenEightyP/NetNews huggingface dataset:
From: Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald)
Newsgroups: sci.space
Subject: Re: Special Relativity
Date: 4 Sep 92 02:59:51 GMT
Organization: Dartmouth College, Hanover, NH
X-Posted-From: InterNews1.0a4@newshost.dartmouth.edu

In article <Bu10or.MKw.1@cs.cmu.edu>
18084TM@msu.edu (Tom) writes:

> I bet you can't describe the difference between these interpretations
> of the same event, save that they are made by different observers.
> One of the standard results of SR is the non-objectiveness of any frame.
> (The frame of our near-c trip to M31 becomes inertial when the engines
> are turned off, BTW)

This is the twin paradox: the resolution is in any decent book on SR.
Basically, the twin on Earth ages, because the twin who went to
Andromeda, in order to get back to Earth, had to turn around: turn
around, did you say? This is an acceleration! So the twin in the rocket
was not in an inertial frame, and so is not equivalent to the other.

> Wasn't one of the confirmations of SR that unstable particles moving at
> near c would decay past their expected places?  From our point of view,
> their time slowed down.  From their point of view, our frame got shorter.
> Aren't both interpretations correct?  We can easily extrapolate to the
> case of an observer at lightspeed, as the original poster (whose name
> I've stupidly deleted, and forgotten) has done.

This is the barn-and-pole paradox, explained very well in Spacetime
Physics, by Taylor & Wheeler. Also, that we can detect cosmic ray muons
at all at sea level was an early confirmation of SR: they should all
decay in the upper atmosphere, but instead make up the dominant
component of cosmic rays, at sea level. Again, see Taylor & Wheeler.

> Isn't all math, from calculus on up, based on an understanding
> of limits?  I think c = infinity, (in the photon's frame) is a pretty
> good way to get an intuitive idea of what's going on.  After all, c
> is a limit, not a speed (for anything with mass).
> 
> Has anyone done any actual math in this vein?

See Taylor & Wheeler. c = c, not infinity; a photon has zero rest mass,
and any such particle can only travel at c, because of the elementary
result E^2 = m^2 c^4 + p^2 c^2, where E = energy, m = rest mass, p =
momentum, and you know c.

This discussion is very elementary and belongs in sci.physics, anyway:
please take it there, after looking at Taylor & Wheeler, Spacetime
Physics.
Xref: sparky sci.space:12390 news.answers:2753
From: rabjab@golem.ucsd.edu (Jeff Bytof)
Newsgroups: sci.space
Subject: Laser distance record?
Date: 3 Sep 92 18:45:45 GMT
Organization: sio
NNTP-Posting-Host: lutherlab.ucsd.edu

To date, what is the farthest that a laser has been seen from?

I recall a successful experiment sending a laser beam from the
Earth to a Surveyor lander on the Moon in the sixties.  That would
make the current record approx. 384,400 km?

Jeff Bytof
rabjab@golem.ucsd.edu
Newsgroups: sci.space
From: digests%isu.isunet.edu@msu.edu (Space Digest maintainer)
Subject: Space Digest V15 #141
X-Added: Forwarded by Space Digest
Organization: [via International Space University]
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU
Distribution: sci
Date: Wed, 26 Aug 1992 17:03:28 GMT



>NASA is not some evil entity trying to keep humanity from developing space;
>they're trying to help in their own way, but they have their own problems.

NASA is not TRYING to keep humanity from developing space, they are simply
SUCCEEDING (in some cases) at keeping humanity from developing space.
Evil (or at least bad) acts often come from good intentions.

>Without the promise of near-term profit, you won't get industry to do what's
>necessary, so the government does things like SSF, and perhaps more
>importantly,  SSTO and NASP.

IMHO, you have the motivations reversed.  It is not that NASA is picking
up on a very real and important need that private investment has simply
ignored; it is that NASA, being an arm of the gov., has a literal
monopoly on what happens in space, and like all monolpolies, the only
benefits are to the holders of the monopoly.

Consider the phrase 'what's necessary' above.  Only someone who has
completely accepted a monopoly situation would think in terms of
'necessary' instead of 'desired, useful, marketable', etc.
Necessary for what? To whom? By whose standards?  The holders of the
monopoly, of course!

-Tommy Mac                     .  "                  +
.------------------------  +                      *       +
|   Tom McWilliams; scrub       ,     .                        "        +
|  astronomy undergrad, at     *       +;.     .  '             There is
| Michigan State University   '                      .    "   no Gosh!
|   18084tm@ibm.cl.msu.edu                        '      ,   *
|       (517) 355-2178       ;  +  '                                 *
'-----------------------
Newsgroups: sci.space
From: xrcjd@resolve.gsfc.nasa.gov (Charles J. Divine)
Subject: Re: Private space ventures
Organization: NASA Goddard Space Flight Center, Greenbelt MD
Date: Tue, 25 Aug 1992 21:45:47 GMT

In article <8780.2339210127@kcbbs.gen.nz> Simon_Demler@kcbbs.gen.nz (Simon Demler) writes:
>> [It bugs me that there are people like H Ross Perot, who
>> themselves have enough cash to finance their own space
>> programs, but that none, so  far, has underwritten one.]
>
>Does it also bother you that these people could be spending some money 
>on the drought problems in Africa rather than on some space program...You 
>must be one of those space for the sake of space of types...
>
>Come on get real...there are MUCH larger problems that need solving 
>on this planet before trying to get peoples private wealth for space 
>purposes..

Implicit in this argument is the notion that activities in space 
subtract from efforts to solve problems on earth.

This is simply not true.

In the Washington Post (and I suspect other newspapers) was a 
major story this morning:  Hurricane hits Florida.  10 people might
have died.  

If we had followed your approach over the past 40 years, the 
headlines might have read:  Surprise hurricane hits Florida!
Thousands die!

That's the way things used to be -- before weather satellites.

Western civilization has been one of the greatest engines for
solving of problems the human race has ever created.  But it
didn't accomplish all this by turning inward.  It did it by
turning outward and embracing the world and persuing discovery.



-- 
Chuck Divine
From: szabo@techbook.com (Nick Szabo)
Newsgroups: sci.space
Subject: Re: Private space ventures
Date: 3 Sep 92 15:01:49 GMT
Article-I.D.: techbook.1992Sep3.150149.20269
Organization: TECHbooks --- Public Access UNIX --- (503) 644-8135

In article <BtK3nK.HGp@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>>[GPS, satellite recievers, etc.]
>It won't help.  The belittlers will just redefine the "space program"
>they are criticizing to exclude these obviously-useful things.

Sadly, what is in fact happening is that many space activists define
the "space program" to exclude these things.

-- 
szabo@techbook.COM  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81)
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.space
Subject: Re: With telepresence, who needs people in Earth orbit?
Date: 26 Aug 92 16:39:36 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <RUCA.92Aug25115643@pinkie.saber-si.pt> ruca@pinkie.saber-si.pt (Rui Sousa) writes:
>In article <1992Aug24.043114.23137@ke4zv.uucp> gary@ke4zv.uucp (Gary Coffman) writes:
>
>   Not the same thing at all. Except for the Viking landers, *none* of the
                                              ^^^^^^^^^^^^^^
>   spacecraft that ventured beyond the Moon have been able to manipulate
                             ^^^^^^^^^^^^^^^
>   their environment. They have been mere sensor platforms. The common
>
>You are forgetting the Luna series and the Viking landers. Though not 
>autonomous they certainly could turn rocks over...

Try again.

Gary
Newsgroups: sci.space
From: pgf@srl02.cacs.usl.edu (Phil G. Fraering)
Subject: Re: With telepresence, who needs people in Earth orbit?
Organization: Univ. of Southwestern Louisiana
Date: Fri, 4 Sep 1992 15:29:17 GMT

szabo@techbook.com (Nick Szabo) writes:

>The problem is, projects like TSS and SSF are designed around a launcher 
>that doesn't give frequent and simple access to orbit.  TSS, for example,
>could easily have been a quarter the size, a tenth the cost, teleoperated, 
>launched commercially, and provided 90% of the needed data.
[...]

Just commenting...

Anyone notice that despite being designed for the Shuttle, TSS was
_not_ apparently designed for astronaut servicing?

Aster all the trouble the program has experienced from being
tied to the Shuttle, they should have at least taken advantage
of some of the advantages they could have gotten, and put someone
outside in a spacesuit to shove on it or kick it or wave a dead
chicken over it or whatever needed to be done...

Moral of the story: If you insist on having the people there,
at least use them... the way the mission was run, it might
as well have been teleoperated, apparently.

--
Phil Fraering pgf@srl0x.cacs.usl.edu where the x is a number from 1-5.
Phone: 318/365-5418 SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560
If seven maids with seven brooms swept for half a year,
do you think, the Walrus asked, that they could make it clear?
I doubt it, said the Carpenter, and shed a bitter tear.
---------
"NOAH!"                        \           \ Lewis Carrol
"Yes lord?"                     > Bill Cosby, The Story of Noah
"HOW LONG CAN YOU TREAD WATER?"/




Newsgroups: sci.space,sci.astro
From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: UARS Update - 08/31/92
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  UARS
Reply-To: baalke@kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Tue, 1 Sep 1992 06:03:06 GMT

Forwarded from the SpaceLink BBS

                       UARS STATUS REPORT
                        August 31, 1992

UPPER ATMOSPHERE RESEARCH SATELLITE (UARS): Attempts to restart
the Improved Stratospheric and Mesospheric Sounder (ISAMS)
chopper wheel motor have not been successful.  The motor stopped
working on July 29. The chopper wheel breaks up or "chops" the
incoming light beam for analysis. Automated attempts to restart
the chopper motor continue. ISAMS measures ozone, nitrogen
compounds and other gasses important in ozone depletion. Most of
these compounds are measured by other UARS instruments, so the
loss of ISAMS has minimal impact on the UARS science mission at
this time.  UARS launched September 12, 1991 from the Space
Shuttle Discovery.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     | 

Newsgroups: sci.space
From: martin@space.ualberta.ca (Martin Connors)
Subject: Re: Mars Observer Press Kit (long)
Reply-To: martin@space.ualberta.ca (Martin Connors)
Organization: University Of Alberta, Edmonton Canada
Date: Fri, 4 Sep 1992 15:27:41 GMT

In article <1992Sep3.220324.941@elroy.jpl.nasa.gov>  
baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:
>                               MARS OBSERVER
>                                 PRESS KIT
> Mars Observer Laser Altimeter (MOLA)
> 
>      The Mars Observer Laser Altimeter uses a very short
> pulse of laser light to measure the distance from the
> spacecraft to the surface with a precision of several meters.
> These measurements of the topography of Mars will provide a
> better understanding of the relationship among the Martian
> gravity field, the surface topography and the forces
> responsible for shaping the large-scale features of the
> planet's crust.

This is great - comparable resolution in altimetry for Venus (from  
Magellan) and Mars. If only something as good existed for Earth! I think  
there is an 'etopo5' database for Earth but the precision is likely not as  
great especially for ocean floor which is 70% of Earth. Comments?

Martin Connors
University of Alberta
Newsgroups: sci.space
From: knapp@spot.Colorado.EDU (David Knapp)
Subject: Re: Venus orbiters
Organization: University of Colorado, Boulder
Date: Tue, 1 Sep 1992 14:10:12 GMT

In article <9209010437.AA10756@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes:
>
>
>Will the trajectory of Pioneer Venus as it burns up provide useful
>information for the planning of the Magellan aerobraking experiment?
>(Density and drag at various altitudes, etc.)


The density and drag at various altitudes is strongly correlated to solar 
activity.  This is one factor which will help determine the time of demise 
of the PVO itself.  Since we cannot know exactly what the solar activity
will be in the future, planning for aerobraking is somewhat like weather
forecasting.  

-- 
David Knapp                                      University of Colorado, Boulder
Highly Opinionated, Aging  and                      knapp@spot.colorado.edu
Perpetual Student of Chemistry and Physics.
            Write me for an argument on your favorite subject.
Newsgroups: sci.space
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Balloon Launches
Date: Sun, 23 Aug 1992 22:41:28 GMT
Organization: U of Toronto Zoology

In article <RUCA.92Aug19133647@pinkie.saber-si.pt> ruca@pinkie.saber-si.pt (Rui Sousa) writes:
>I don't think dirigibles are fast enough to be really useful to give a
>first kick to a Pegasus launcher, for example. That's why they use B-52's.

Indeed, the speed of the B-52 is relatively unimportant.  The main benefit
Pegasus gets from air launch, apart from bypassing a lot of bureaucracy
associated with fixed launch sites, is thinner air.  (The speed is useful,
just not very important.)
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  henry@zoo.toronto.edu  utzoo!henry
From: wats@scicom.AlphaCDC.COM (Bruce Watson)
Newsgroups: sci.space
Subject: Re: Martian Chronology
Date: 25 Aug 92 17:36:25 GMT
Distribution: sci
Organization: Alpha Science Computer Network, Denver, Co.

In article <1992Aug24.163033.21556@pixel.kodak.com+ dj@ssd.kodak.com (Dave Jones) writes:
+In article <BtDrny.AHq.1@cs.cmu.edu| kfree@pnet01.cts.com (Kenneth Freeman) writes:
+|Has a Martian calender been worked up for the benefit of future
+|colonists? Would the moons have a practical or a _pro forma_ role?
+|---
+|Free Tibet.
+|UUCP: {ucsd nosc}!crash!pnet01!kfree INET: kfree@pnet01.cts.com
+
+A Martian calendar was written up in either "Galaxy" or "Astounding"
+SF magazines  in the 50s.  It may even have been an Asimov article.
+
+The real question is: would any colonists care enough about the seasons
+on Mars to want to track them accurately with a calendar?

Maybe not the seasons, but the day would be very important. Navigation
will probably be done with artificial satellites (GPS-like) rather
than the stars.

I once entertained putting together a Nautical Alamanac for Mars
for the year 1986 (My best guess for a manned mission) for navigational
purposes. It would have been simpler to put everything in terms of
Martian days than to keep everything in Earth days.
+
-- 
Bruce Watson (wats@scicom)  Tumbra, Zorkovick; Sparkula zoom krackadomando.
From: szabo@techbook.com (Nick Szabo)
Newsgroups: sci.space
Subject: Re: Private space ventures
Date: 23 Aug 92 09:09:46 GMT
Article-I.D.: techbook.1992Aug23.090946.5294
Organization: TECHbooks --- Public Access UNIX --- (503) 644-8135

In article <BtD28H.5sA@news.cso.uiuc.edu> jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes:
>

>>[Another poster asks why Bill Gates et. al. have not invested in
space]
>
>	Actually, according to the internal IBM equivalent of netnews, Gates has
>started investing in movies in the last few months.

In fact, Gates and Microsoft co-founder Paul Allen have invested in
Skypix, the direct broadcast satellite company.  Since they'll be
beaming movies, it's interesting to see that Gates is also investing
in the movies themselves.


-- 
szabo@techbook.COM  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) 
Newsgroups: sci.space
From: tkelso@afit.af.mil (TS Kelso)
Subject: Two-Line Orbital Element Set Format
Keywords: Satellite, Orbital Elements, Keplerian, Format
Organization: Air Force Institute of Technology
Date: Fri, 28 Aug 1992 23:29:20 GMT

As a service to the satellite user community, the following description of the
NORAD two-line orbital element set format is uploaded to sci.space and
rec.radio.amateur.misc on a monthly basis.  The most current orbital elements
from the NORAD two-line element sets are carried on the Celestial BBS, (513)
427-0674, and are updated daily (when possible).  Documentation and tracking
software are also available on this system.  The Celestial BBS may be accessed
24 hours/day at 300, 1200, 2400, 4800, or 9600 bps using 8 data bits, 1 stop
bit, no parity.  In addition, element sets (also updated daily) and some
documentation and software are also available via anonymous ftp from
archive.afit.af.mil (129.92.1.66) in the directory pub/space.

==============================================================================

Data for each satellite consists of three lines in the following format:

AAAAAAAAAAA
1 NNNNNU NNNNNAAA NNNNN.NNNNNNNN +.NNNNNNNN +NNNNN-N +NNNNN-N N NNNNN
2 NNNNN NNN.NNNN NNN.NNNN NNNNNNN NNN.NNNN NNN.NNNN NN.NNNNNNNNNNNNNN

Line 0 is a eleven-character name.

Lines 1 and 2 are the standard Two-Line Orbital Element Set Format identical
to that used by NORAD and NASA.  The format description is:

Line 1
Column     Description
 01-01     Line Number of Element Data
 03-07     Satellite Number
 10-11     International Designator (Last two digits of launch year)
 12-14     International Designator (Launch number of the year)
 15-17     International Designator (Piece of launch)
 19-20     Epoch Year (Last two digits of year)
 21-32     Epoch (Julian Day and fractional portion of the day)
 34-43     First Time Derivative of the Mean Motion
        or Ballistic Coefficient (Depending on ephemeris type)
 45-52     Second Time Derivative of Mean Motion (decimal point assumed;
           blank if N/A)
 54-61     BSTAR drag term if GP4 general perturbation theory was used.
           Otherwise, radiation pressure coefficient.  (Decimal point assumed)
 63-63     Ephemeris type
 65-68     Element number
 69-69     Check Sum (Modulo 10)
           (Letters, blanks, periods, plus signs = 0; minus signs = 1)

Line 2
Column     Description
 01-01     Line Number of Element Data
 03-07     Satellite Number
 09-16     Inclination [Degrees]
 18-25     Right Ascension of the Ascending Node [Degrees]
 27-33     Eccentricity (decimal point assumed)
 35-42     Argument of Perigee [Degrees]
 44-51     Mean Anomaly [Degrees]
 53-63     Mean Motion [Revs per day]
 64-68     Revolution number at epoch [Revs]
 69-69     Check Sum (Modulo 10)

All other columns are blank or fixed.

Example:

NOAA 6
1 11416U          86 50.28438588 0.00000140           67960-4 0  5293
2 11416  98.5105  69.3305 0012788  63.2828 296.9658 14.24899292346978
-- 
Dr TS Kelso                           Assistant Professor of Space Operations
tkelso@afit.af.mil                    Air Force Institute of Technology
Newsgroups: sci.space,sci.astro
From: JDAVIS@GRIFFIN.UGA.EDU (Jerry Davis)
Newsgroups: sci.space
Subject: Soviet rovers on Mars
Date: 28 Aug 92 21:04:21 GMT
Article-I.D.: cs.Btpvns.o1.1
Distribution: sci
Organization: Georgia Ag. Exp. Sta.
X-Added: Forwarded by Space Digest
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU


>Date: 24 Aug 92 23:37:54 GMT
>From: Bill Higgins-- Beam Jockey <higgins@fnalf.fnal.gov>

>(I'm not familiar with their instrument load). Phobos 2 and one of the
>Soviet Mars landers carried tiny rovers, too.  Or do we only count
>spacecraft that succeeded?  ^^^^
                               ?
Tiny?  I'm not sure about Phobos 2, but 2 weeks ago I saw a Soviet Mars
rover at the Air Force Museum, Wright Patterson AFB and it was pretty
big.  Probably at least as large as a 12 - 16 hp riding lawnmower with
6 wheels and lots more mass.

They also had a Soyuz return capsule.  I would hate to spend a year
in micro-gravity and then ride back in that rascal.  It didn't look
very comfortable.  It is a big improvement over the Vostok return
capsule however.  I never knew that the hatch was blown at 22,000 ft
and the cosmonaut jumped out. Sheeeesh.

Jerry
From: szabo@techbook.com (Nick Szabo)
Newsgroups: sci.space
Subject: Re: Saturn class (Was: SPS feasibility and other space
Date: 3 Sep 92 15:42:01 GMT
Article-I.D.: techbook.1992Sep3.154201.21057
Organization: TECHbooks --- Public Access UNIX --- (503) 644-8135

In article <1992Aug25.210314.14787@iti.org> aws@iti.org (Allen W. Sherzer) writes:
>SS Freedom construction and supply IS a viable commercial market for 
>HLVs this decade.

This is a sad example of the Orwellian perversion of the word
"commercial" being undertaken by NASA & freinds.  The common, and only
useful in this case, definition of commercial is those projects for
which funding originates in the private sector.  What we would have here
is traditional contracting, perhaps modified in process to be called
"commercial", but subject to the same political winds and probably the
same efficiencies.  We have NASA still dictating architecture to
industry and serving its own obscure needs, instead of following the
lead of commerce and serving the needs of commerce.

In this case, Clinton/Gore with their emphasis on EOS, and Bush/Quayle 
with their 10% across-the-board spending cut, combined with next year's 
budget-conscious Congress could easily axe SSF.  Whatever the political
support it may have garnered from zealots in the past, the political
landscape during the next few years is going to be greatly changed.
In the early 80's, with the Cold War overshadowing any concern for 
deficits, I could collude with people like Sen. Slade Gorton (R-WA) 
to get SSF funded and get Boeing the contract (that sad tale has been 
told elsewhere).  That won't work with somebody like Rod Chandler, 
this year's Republican for Senate from Washington State that whose
main campaign theme is cutting the Federal Budget -- quite a rare
campaign theme, if you think back to previous years when budget-cutting
was portrayed as a vice, not a virtue.

Furthermore, there is still intense political pressure to use the Shuttle.  
The chances of SSF ever being inhabited are less than 50%, and the chances
of it being serviced by other than the Shuttle, if it did get that
far, are probably less than 25%.  A 13% chance of a couple $billion in 
revenue in five to fifteen years is a net present value on the order
of $100 million, an insignificant fraction of the cost to develop this 
monster.  

This is nowhere close to being sufficient to attract private 
investment, nor would the resulting monster save any money for 
SSF, not to mention the other 90% of the space program. It may yet 
"justify" the pork barrel to start rolling for NLS, subsidized by the IRS 
every step of the way, and improving launch services not a whit. Why are
you expending effort creating arguments for the NLS crowd?


-- 
szabo@techbook.COM  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81)