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Date: Thu, 4 Mar 93 06:38:05
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V16 #270
To: Space Digest Readers
Precedence: bulk
Space Digest Thu, 4 Mar 93 Volume 16 : Issue 270
Today's Topics:
Apollo Missions (Recollections)
A response from Anonymous
Bullets in Space
Galileo Earth-Moon Animation
Getting people into S (2 msgs)
Gravity simulations
KIDS
Looking for Visible/IR Spectrum of Moonlight
Mars Observer Orbital Elements
NASP (was Re: Canadian SS
Space Scientist (3 msgs)
Space Station LaFave (SSL :-)
Spy Sats (Was: Are La
Why Apollo didn't continue?
Welcome to the Space Digest!! Please send your messages to
"space@isu.isunet.edu", and (un)subscription requests of the form
"Subscribe Space <your name>" to one of these addresses: listserv@uga
(BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
(THENET), or space-REQUEST@isu.isunet.edu (Internet).
----------------------------------------------------------------------
Date: 3 Mar 93 17:35:44 GMT
From: Ed Faught <faught@berserk.ssc.gov>
Subject: Apollo Missions (Recollections)
Newsgroups: sci.space
>>
>> Anyone else with good memories?
>>
We were in the U.S. Army's Primary Helicopter Training School at Ft.
Wolters, Texas. Since this was also warrant officer's training we had not been
allowed to watch television for a couple of months. It was a really BIG deal to
see anything on TV, and we were allowed to watch the best show ever televised.
Anyone involved in similar military training can well imagine the tremendous
feelings of pride and the morale boost.
In a similar vein, I was standing right next to a Soviet physicist at
Fermilab discussing our differences in equipment design philosophy while
watching Apollo/Soyuz going over shortly after separation.
--
Ed Faught WA9WDM faught@berserk.ssc.gov
Superconducting Super Collider Laboratory
------------------------------
Date: 2 Mar 93 13:29:10 GMT
From: Alex Martelli <martelli@cadlab.sublink.org>
Subject: A response from Anonymous
Newsgroups: news.admin.policy,alt.privacy,comp.org.eff.talk,sci.space,sci.astro
bdb@becker.GTS.ORG (Bruce Becker) writes:
...
: Anonymous postings are a really good example
: of things that are to be judged by content,
: since the typical responses of "oh that's a
: posting by X, he's an idiot", or "Aha, Y is
: always making good points" are not able to
: be made.
This would only hold for an anonymous server which hid any hint
of authorial individuality - not the way those I know work. As
of now, I see the author identified as, for example, wi.6686,
and after a few posts I'm able to make the same X/Y judgments
you decry.
I find some validity to all other points you make, particularly:
: Persons whose private concerns
: may be at odds with public perceptions
: have legitimate reasons for maintaining
: privacy, even though no law is broken.
John Stuart Mill makes a similar point about the chilling effect
of public disapproval, though he is not talking about anonymity,
in "On Liberty".
Alex
--
Email: martelli@cadlab.sublink.org Phone: ++39 (51) 6130360
CAD.LAB s.p.a., v. Ronzani 7/29, Casalecchio, Italia Fax: ++39 (51) 6130294
------------------------------
Date: 3 Mar 93 17:27:35 GMT
From: "Glenn R. Stone" <gs26@prism.gatech.EDU>
Subject: Bullets in Space
Newsgroups: sci.space
In <731117525.0@aldhfn.akron.oh.us> Ryan_Potts@aldhfn.akron.oh.us (Ryan Potts) writes:
>But isn't o2 needed to aid in the combustion of the gunpowder in the round? :)
Nope. Remember that until the moment of ignition, the case is
sealed by the bullet (shotgun shells excepted); any O2 needed
for the reaction had better be present in the cartridge with
the powder, because it's sure not going to get in there once
things start burning....
Glenn R. Stone (glenns@eas.gatech.edu)
Do not meddle in the affairs of wizards; it makes them soggy and hard to light.
------------------------------
Date: 3 Mar 1993 17:05 UT
From: Ron Baalke <baalke@kelvin.jpl.nasa.gov>
Subject: Galileo Earth-Moon Animation
Newsgroups: sci.space,sci.astro,alt.sci.planetary
The hqx file for the Galileo Earth-Moon animation was inadvertently ftp'd
to Ames in binary mode, and this has caused some problems with some of the
uncompressors such as Stuffit and Compact Pro. The file has been
ftp'd in ascii to rectify the problem. I apologize for any inconvenience
this may have caused. The animation can be run using either NIH Image
or Quicktime 1.5. A fli version of the animation is expected to be ready
by this Friday (March 5). Thanks again to Paul Geissler and Larry Kendall
for creating the animation and making it available.
ftp: ames.arc.nasa.gov (128.102.18.3)
user: anonymous
cd: pub/SPACE/ANIMATION
files:
Earth_Moon_Movie.Hqx
Earth_Moon_Movie.txt
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible.
|_____|/ |_|/ |_____|/ | Walt Disney
------------------------------
Date: Wed, 3 Mar 1993 15:47:41 GMT
From: Mary Shafer <shafer@rigel.dfrf.nasa.gov>
Subject: Getting people into S
Newsgroups: sci.space
In article <14293.409.uupcb@the-matrix.com> roland.dobbins@the-matrix.com (Roland Dobbins) writes:
JL>Could that be the vehicle commonly called the flying Bumble Bee, wh
JL>clai to fame in the ordinary world is the vehicle that opened the s
JL>and each episode of the six million dollar man. If I recall correct
JL>was aeronautically considered to be unflyable, but flew anyway and
JL>for a while touted as a great instrument for flight to and from low
JL>orbit. It finally crashed on descent when it touched down and did a
JL>up unfortunately a Helo was in the way and the two collided as the
JL>goes. I think That its prototypes and other s are still on display
JL>the yearly aeronautical show at Edwards airforce base.
First, no one ever called the lifting bodies "Flying Bumblebees". The
popular press (i.e. Popular Mechanics and Popular Science) called them
"Flying Bathtubs". We called them lifting bodies.
Second, there are _two_ lifting bodies shown in the sequence opening
the Six Million Dollar Man. The first vehicle, which comes off the
hooks, is the HL-10. The second vehicle, which crashes, is the M2-F2.
Third, the M2-F2 hit the ground, as may be plainly seen in the
footage. The M2-F2 had a coupled roll-spiral PIO (a so-called
"lateral phugoid") that had been seen in in-flight simulation in the
NT-33A and in up-and-away flight. Bruce Peterson was somewhat out of
position on final and became distracted by the location of the
firetrucks and the helicopter and he excited the roll-spiral PIO too
close to the ground to recover.
Fourth, the HL-10 is on a plinth outside Dryden (it never crashed, but
the Los Angeles Museum of Science and Industry dropped it from their
ceiling onto its back when a cable broke and it had to be rebuilt).
The M2-F2 was rebuilt as the M2-F3 and is now hanging in the
Milestones of Flight Gallery at the National Air and Space Museum.
The M2-F1 is in the heat facility hangar here at Dryden. The X-24A
was rebuilt (no crash, though) as the X-24B and it's now on display at
the Air Force Museum at Wright-Patterson.
Fifth, these were not prototypes, these were experimental aircraft.
As I recall, that particular lifting body was called the HL-10, and it
was most certainly _not_ designed *not* to fly . . . .
Damned straight.
--
Mary Shafer DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
shafer@rigel.dfrf.nasa.gov Of course I don't speak for NASA
"A MiG at your six is better than no MiG at all." Unknown US fighter pilot
------------------------------
Date: 3 Mar 93 18:17:51 GMT
From: "Richard A. Schumacher" <schumach@convex.com>
Subject: Getting people into S
Newsgroups: sci.space
"PIO" = Pilot Induced Oscillation.
------------------------------
Date: 3 Mar 93 16:24:33 GMT
From: Bill Broadley <broadley@neurocog.lrdc.pitt.edu>
Subject: Gravity simulations
Newsgroups: sci.space
I'd like to get ahold of some source code that would allow me to do
a 2d or 3d gravity simulation of N object in O(N) time.
I have several references to such articles from the sci.space FAQ but would
prefer to start with existing source code (preferably C).
I'd like to write an X11 gravity simulation that would be as much fun
to play with as Xspringies, as well as do some larger simulations of many
bodies. Anyone out there have some source around?
If not I'll look up the references (I found them in the FAQ), and implement
one of those (anyone want to help?)
--
Bill 1st> Broadley@neurocog.lrdc.pitt.edu
Broadley@schneider3.lrdc.pitt.edu <2nd 3rd> Broadley+@pitt.edu
Linux is great. Bike to live, live to bike. PGP-ok
------------------------------
Date: 3 Mar 1993 11:43:09 -0500
From: Bob McGwier <n4hy@idacrd.ccr-p.ida.org>
Subject: KIDS
Newsgroups: sci.space
I really had it brought home to me yesterday how far in the past the moon
program is to today's kids. I was watching Jeopardy which comes on here
after the news (I was in my couch potato mode). The final Jeopardy
question was `Eugene Cernan was the last person to walk here'. One kid
got it right and admitted that he guessed since he could not figure
out anyplace else that people had gone to and not returned. I really
felt the loss of these types of goals for our society most keenly seeing
the ignorance displayed about one of our greatest technological achievements.
Bob
--
------------------------------------------------------------------------------
Robert W. McGwier | n4hy@ccr-p.ida.org
Center for Communications Research | Interests: amateur radio, astronomy,golf
Princeton, N.J. 08520 | Asst Scoutmaster Troop 5700, Hightstown
------------------------------
Date: Wed, 3 Mar 93 14:30:29 GMT
From: Ata Etemadi <atae@spva.ph.ic.ac.uk>
Subject: Looking for Visible/IR Spectrum of Moonlight
Newsgroups: sci.space
G'Day
I am looking for a digital (or as a last resort, hardcopy) spectrum of
moonlight covering the visible and IR as observed by a spacecraft (ie no
atmospheric effects). If the data set covers all the phases of the moon
it would be ideal. This data is for use by our atmospheric modellers
and will be used for research leading hopefully to publication(s). Any
"rules-of-the-road" associated with the use of this data will be gladly
adhered to. Uoyr help, pointers to sites, suggestions, comments etc..
would be greatly appreciated.
many thanks in advance
Ata <(|)>
--
| Mail Dr Ata Etemadi, Blackett Laboratory, |
| Space and Atmospheric Physics Group, |
| Imperial College of Science, Technology, and Medicine, |
| Prince Consort Road, London SW7 2BZ, ENGLAND |
| Internet/Arpanet/Earn/Bitnet atae@spva.ph.ic.ac.uk or ata@c.mssl.ucl.ac.uk |
| Span SPVA::atae or MSSLC:atae |
| UUCP/Usenet atae%spva.ph.ic@nsfnet-relay.ac.uk |
------------------------------
Date: Tue, 2 Mar 1993 22:02:01 GMT
From: "Carlos G. Niederstrasser" <phoenix.Princeton.EDU!carlosn@CRABAPPLE.SRV.CS.CMU.EDU>
Subject: Mars Observer Orbital Elements
Newsgroups: sci.space
In article <2MAR199300411325@kelvin.jpl.nasa.gov>
baalke@kelvin.Jpl.Nasa.Gov (Ron Baalke) writes:
>
> MARS OBSERVER ORBITAL ELEMENTS
> March 1, 1993
>
>
> INTERPLANETARY CRUISE
>
> Semi-major axis 197163351.177 km
> Eccentricity 0.23885397 deg
> Inclination 1.294 deg
> Argument of periapsis -173.656 deg
> Ascending node -177.619 deg
> Mean anomaly of epoch 110.042 deg
>
> Epoch of elements: March 18, 1993 18:53:38.38 Ephemeris Time
> Coordinate system: Sun-centered, Earth Mean Orbit and Equinox
> of Epoch J2000
>
> _________________________________________________________________
>
>
> CAPTURE ORBIT
>
> Semi-major axis 42923.941 km
> Eccentricity 0.907977 deg
> Inclination 89.000 deg
> Argument of periapsis 112.990 deg
> Ascending node -106.453 deg
> Mean anomaly of epoch -180.000 deg
>
> Epoch of elements: August 26, 1993 10:10:52.78 Ephemeris Time
> Coordinate system: Mars-centered, Mars Mean Equator and IAU
> Vector of Epoch
>
> _________________________________________________________________
>
>
> MAPPING ORBIT
>
> Semi-major axis 3766.159 km
> Eccentricity 0.004049 deg
> Inclination 92.869 deg
> Argument of periapsis -90.0 deg
> Ascending node 261.590 deg
> Mean anomaly of epoch 0.000 deg
>
> Epoch of elements: December 6, 1993 00:00:00.00 Ephemeris Time
> Coordinate system: Mars-centered, Mars Mean Equator and IAU
> Vector of Epoch
What are the inclinations given above with respect to?
---
---------------------------------------------------------------------
| Carlos G. Niederstrasser | It is difficult to say what |
| Princeton Planetary Society | is impossible; for the dream of |
| | yesterday, is the hope of today |
| | and the reality of tomorrow |
| carlosn@phoenix.princeton.edu |---------------------------------|
| space@phoenix.princeton.edu | Ad Astra per Ardua Nostra |
---------------------------------------------------------------------
------------------------------
Date: Wed, 3 Mar 1993 15:55:03 GMT
From: Mary Shafer <shafer@rigel.dfrf.nasa.gov>
Subject: NASP (was Re: Canadian SS
Newsgroups: sci.space
On 2 Mar 93 08:44:00 GMT, roland.dobbins@the-matrix.com (Roland Dobbins) said:
CO>> Aerospace Daily also reports that NASA research on advanced
CO>> subsonic and supersonic transport aircraft would get a big
CO>> increase under Clinton's budget plan, with $550 million more
CO>> programmed in fiscal years 1994-97, and another
CO>> $267 million scheduled for FY '98.
CO>
CO>What about NASP???
R> Errr . . . that _is_ NASP.
No, that's HSCT--High Speed Civil Transport.
Notice that Aerospace Daily refers to _transport_ aircraft.
NASP, which is a single-stage-to-orbit airbreathing horizonal-takeoff
vehicle, is not a transport aircraft. It's probably dead. Physics
has apparently finally reared its ugly head and driven a stake through
the heart of the program. About time....
--
Mary Shafer DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
shafer@rigel.dfrf.nasa.gov Of course I don't speak for NASA
"A MiG at your six is better than no MiG at all." Unknown US fighter pilot
------------------------------
Date: Wed, 3 Mar 1993 14:15:54 GMT
From: "Frederick A. Ringwald" <Frederick.A.Ringwald@dartmouth.edu>
Subject: Space Scientist
Newsgroups: sci.space,sci.research.careers
In article <davidlai.731055215@unixg.ubc.ca>
davidlai@unixg.ubc.ca (David Lai) writes:
> I'm interested in becoming a space scientist, like those who work for
> NASA. I want to know what qualifications I need. Do those scientists who
> work for NASA are all Ph.D.s? Is there any recommendations for what
> degrees to get? Thanks!
An absolute commitment, a tremendous amount of hard work of high
quality, a great deal of talent, and a generous portion of luck are
what are required these days, in addition to a Ph.D. A Ph.D. is no
guarantee of getting a job as a space scientist, since the space field
is in a very depressed state. I should know, since I got my Ph.D.
recently. My thesis is a veritable tree-killer at 287 pages; not a
record, but pleasing in that every time I look at it again, new science
pops out. TOMORROW I am emigrating to England for a research fellowship
in astrophysics. This was after a 9-month job search of excruciating
proportions, involving sending 45 applications and making 15 short
lists, often at prestigious places such as Harvard, Oxford, STScI, and
Chicago, so the problem was probably not me, since every last one of
these jobs had over 100 people applying for them. Two offers were made,
and I felt very lucky for them!
A Ph.D. is NOT of a guarantee of employment in most physical sciences
these days, even obviously and immediately practical ones such as solid
state physics. Things are bad all over. You might have heard that there
is a "shortage" of scientists, but you can stop believing these rumors
right now: many of them can be traced to a badly-mistaken NSF report,
written before the end of the Cold War and the current economic
slowdown, which didn't do a very careful analysis of the job market,
anyway.
Then again, if you really, REALLY want to become a space scientist, go
ahead and get your Ph.D. After all, Jesse Greenstein managed to get a
job in astronomy during the depression of the '30s. Just be sure, very
sure, to dedicate yourself to becoming really, REALLY good at whatever
it is you do. There might be jobs, for only for exceptionally talented
people. There is certainly no market for mediocre people, and there
will not be, any time in the foreseeable future.
Some fields are better than others, although it's not easy to say much
about this that's sensible. Specializing early has its advantages. It's
certainly the way to get ahead in academia. (That and PUBLISHING.)
Specializing allows you to learn more about your particular topic, and
become better at it - but it's too bad if interest in your topic cools
off, which can happen rapidly and unpredictably. Having a broad
background has its advantages, but there is little demand for a
jack-of-all-trades-and-a-master-of-none. Then again, it is a good idea
to acquire genuinely useful and marketable skills, such as programming,
numerical analysis, and instrumentation skills. Just don't let them be
distractions from whatever your 'thing' is. The current job market is
such that getting a Ph.D. degree should be viewed as an end in
itself, as it traditionally has been in the humanities. You should want
that Ph.D. primarily because it gives you the chance to immerse
yourself in a whole bunch of really neat knowledge for several years.
Disdain for high wages is helpful, too, and if you don't come in on
Saturday, don't bother coming in on Sunday. If the only reason you want
a Ph.D. is as a means to an end, such as a secure, permanent job
exclusively doing research in space science at over $40k/year right out
of grad school (probably more in industry, but they're hurting, too),
you might be disappointed.
And be warned. This evening I had dinner with an exceptionally talented
and imaginative theorist, who's doing his Ph.D. thesis on using wavelet
analysis to analyze the large scale structure of the Universe. He's
having serious problems getting a job, having sent out over 20
applications without a nibble. So, he'll have to stay in grad school an
extra year, so he can keep looking. He's 32 already, and has two young
daughters, so his wife is not too pleased about this and its financial
implications. (She's just submitted her Ph.D. thesis in Spanish.
Solving the two-body problem is not easy, but neither of them have
gotten anything!) Good thing he has his own research grant (under the
NASA Graduate Student Research Program, thanks very much, folks),
otherwise I don't know what he'd do. I don't know what he's going to do
next year, if he doesn't find a job. I suggested he start looking at
industry jobs where he could use what he knows about wavelet analysis,
since it's all the rage in machine vision and pattern recognition. He
could get a cosmology paper or two out on the side, which would make
his company look good, but of course it wouldn't be what they'd be
paying him for. What's most discouraging is not that he's one of the
most intelligent people I know, and a nice guy, too, all too rare in
this field. It's that he's doing the first application of a hot
technique to a hot topic, and getting interesting results. In other
words, that generous portion of LUCK is more important than one might
care to admit.
Of course, if this little rant of mine is enough to dampen your
interest in becoming a space scientist, then forget it. You have to be
rabid to do this. I think it's downright irresponsible that some senior
scientists in comfortable positions are still actively encouraging
young people to go into science. More than enough will do so of their
own accord. It just isn't right to make promises and filch away
someone's youth and give nothing in return. Then again, if you
knowingly and willingly don't mind losing your youth for the very real
possibility of nothing in return, then fine: you should be given the
best education and the best opportunities available, and who knows,
maybe something will come of it. Maybe.
But you don't really get nothing. During those long, lean years of grad
school, at least, you will be doing space science, and that makes you a
space scientist. And of course it is absolutely essential to keep
dreaming those dreams!
(My first task at my new job will be to write proposals for telescope
time for next semester, the deadlines for which are coming up at the
end of the month. I should soon hear whether or not my satellite
proposals for this year have been accepted; the forms for HST time are
intense! People complain that proposal writing is time-consuming - and
it is - but I enjoy dreaming on paper, especially with the bonus that
sometimes they come true...)
Fred Ringwald
as of tomorrow:
Department of Physics
Keele University
Keele, Staffordshire, ST5 5BG
England
Internet: FAR%STARLINK.PHYSICS.KEELE.AC.UK@nss.cs.ucl.ac.uk
It'll certainly be interesting being an American astronomer in England.
I hope I won't have too much trouble with the language. Speaking of
dreams, I simply must go into London for the BIS lectures. I'll post
what I find, as I've not yet seen anything in sci.space from the
world's oldest existing space group.
------------------------------
Date: 3 Mar 93 16:09:25 GMT
From: kjenks@gothamcity.jsc.nasa.gov
Subject: Space Scientist
Newsgroups: sci.space
David Lai (davidlai@unixg.ubc.ca) wrote:
: I'm interested in becoming a space scientist, like those who work for
: NASA. I want to know what qualifications I need. Do those scientists who
: work for NASA are all Ph.D.s? Is there any recommendations for what degrees
: to get? Thanks!
We have many different kinds of people whom you might call "space
scientists." The minimum qualification is a BS in any SCIENCE. ANY
science. A Ph.D. is very helpful in impressing prospective employers
and learning hard part of any scientific endeavor: getting funding.
But it is by no means mandatory for being a "space scientist." And
I've found that it can intimidate some managers to consider hiring
people more educated than themselves. (Sad, isn't it?)
NASA hires mostly US Citizens. Your e-mail address, David, indicates
that you live in Canada. This may be a small impediment to your
getting hired. You'll also have to worry about Resident Alien
status.
Getting hired by NASA itself isn't always easy. You might stand a
better chance hiring on with a support contractor, like Lockheed, which
supports space science applications at one of the NASA Field Centers.
(Lockheed/Houston's switchboard number is (713) 333-5411.) After you
have some experience working with NASA, it's easier to get a job
working FOR NASA.
Currently, there's a hiring freeze on for new Civil Servants at
JSC. But those come and go. Good luck.
-- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office
kjenks@gothamcity.jsc.nasa.gov (713) 483-4368
"Nothing in the world can take the place of persistence.
Talent will not; nothing is more common than unsuccessful men
with talent. Genius will not; unrewarded genius is almost a
proverb. Education will not; the world is full of educated
derilicts. Persistence and determination alone are omnipotent.
The slogan 'Press On' has solved and always will solve the
problems of the human race." -- Calvin Coolidge
------------------------------
Date: 3 Mar 93 18:37:53 GMT
From: Tim Thompson <tjt@Jpl.Nasa.Gov>
Subject: Space Scientist
Newsgroups: sci.space
In response to David Lai's Space Science request, allow me to add my $.02 worth.
My experience is that almost all of the scientists who persue "independent" research,
or run projects, or supervise research, etc., have a Ph.D. Most of those are in
the physical sciences, since that's most of what NASA does, but there are exceptions.
There are also a few "old timers" without Ph.D.'s who run programs or projects, but
I'm sure that would not happen now. If you want a lead role, and the oportunity to
seek out your own grants and research, you must have a Ph.D.
I do not have a Ph.D., I have an M.S. in physics. Although this keeps me out
of the things I have described, it also keeps me out of the attendant problems.
Grants don't just happen, you have to aggressively go after them, and that's work.
I do scientific data analysis, computer programming, and computer system/network
managing. The Ph.D.'s can't get along without me, and I can't get along without
them. I live off their grants.
My opinion is that everyone should go as far as they can, and find the place
that suits there desires and talents. You might find yourself doing something
much different way down the road (I started out as a student of history and languages).
---
ALL OPINIONS EXPRESSED ARE MINE AND NOT JPL's, NOT NASA's.
------------------------------------------------------------
Timothy J. Thompson, Earth and Space Sciences Division, JPL.
Assistant Administrator, Division Science Computing Network.
Secretary, Los Angeles Astronomical Society.
Member, BOD, Mount Wilson Observatory Association.
INTERnet/BITnet: tjt@scn1.jpl.nasa.gov
NSI/DECnet: jplsc8::tim
SCREAMnet: YO!! TIM!!
GPSnet: 118:10:22.85 W by 34:11:58.27 N
------------------------------
Date: Wed, 3 Mar 1993 15:58:13 GMT
From: "Kieran A. Carroll" <kcarroll@zoo.toronto.edu>
Subject: Space Station LaFave (SSL :-)
Newsgroups: sci.space
In article <1993Mar2.203400.13715@aio.jsc.nasa.gov> Dr. Norman J. LaFave <lafave@ial4.jsc.nasa.gov> writes:
>Well, I can discuss a design that some colleagues and I worked on
>and presented during the last redesign. We believe it to be a superior
>design, but we have doubts about whether it will be accepted for the
>upcoming redesign. However, we are hoping that aspects of the
>design will be considered.
>
>Features:
>
>* Alternative modular structures (NO TRUSS):
> ...both of these designs are free of the troublesome flexibility inherent
> in the truss ...
>
This is a curious misapprehension---the truss is there to
separate the solar arrays, to avoid problems like shadowing
of payloads that want to see space, and plume impingement.
Since the solar arrays are large, the separation distance
also needs to be large. The truss itself is designed to
*minimize* flexible effects; the benefit of using a truss
rather than (say) a bunch of modules strung together (a la Mir)
is that a truss can have a much larger bending stiffness for
a given amount of structural mass. For example, most of
the hundred lowest-frequency structural vibration modes of the
current baseline SSF design are solar-array modes, that involve
little bending or twisting of the truss.
Of course, your next suggested design feature does away
with the solar arrays, eliminating one of the main reasons
for wanting the space station to be physically large...
>
>* Primary power source---NOT solar arrays!
>
> RTG pallet---known technology...not subject to shadowing problems...
> eliminates primary plume impingement problems....eliminates largest
> flexibility problems, both control and structural....proven
> safety.
>
RTGs are a reletively mass-inefficient way to generate power,
I seem to remember. They also have limited lifetimes, so they'd
probably have to be replaced every few years. Of course, they'd
eliminate the need for batteries, which also need frequent
replacing, and which also are very massive, so on the basis
of total up-mass they might be a net win. Their main problem
is the issue of safety, both real and perceived. Remembering
Skylab, *many* people would undoubtedly be nervous about having
a large amount (probably several tonnes) of plutonium flying
overhead every day. Come to think of it, *I* would probably
be nervous about this, and I'm a fairly pro-nuclear person.
> Secondary source: Thermal gradient power generation---This is an idea
> we are toying with. The idea is simple.
> Use the huge temperature gradients
> that can be generated between sunlit and shadowed plates to generate
> power. This is much like the concept which was studied to generate power
> using the thermal gradient between the ocean's surface and the ocean
> depths.
>
What's the difference between this concept and the Solar Dynamic
power generation system that was eliminated during the last design
scrub? The latter concept simply used mirrors to heat up a working
fluid, which was passed through (I think) a Stirling (Sterling?) engine
to produce mechanical power, which was then put through an alternator
to produce electrical power; the working fluid was then cooled using
radiators looking at deep space. Of course, you could do the same thing
using thermocouples, but the power conversion efficiency would be much
lower, I think.
BTW, this post isn't meant to be negative, but merely critical
(in the constructive sense---when a new design concept is proposed,
try to define its constraints, so that you can get a handle on
whether its possible for them all to be satisfied at once). It
sure is fun to re-visit the conceptual design stage for space station;
that's the stage when the sky is the limit, before the the inevitable
messy trade-offs force a beautifully simple concept to be bent out
of shape. Reminds me of the good old days of '82 thru '86...
--
Kieran A. Carroll @ U of Toronto Aerospace Institute
uunet!attcan!utzoo!kcarroll kcarroll@zoo.toronto.edu
------------------------------
From: Dean Adams <dnadams@nyx.cs.du.edu>
Subject: Spy Sats (Was: Are La
Newsgroups: sci.space
Sender: netnews admin account <usenet@mnemosyne.cs.du.edu>
Organization: University of Denver, Dept. of Math & Comp. Sci.
References: <14294.409.uupcb@the-matrix.com>
Date: Wed, 3 Mar 93 14:02:47 GMT
Lines: 22
Source-Info: Sender is really news@CRABAPPLE.SRV.CS.CMU.EDU
Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU
roland.dobbins@the-matrix.com (Roland Dobbins) keeps writing:
>Date: 2 Mar 93 08:44:00 GMT
>DA>involved. KH-11 orbits are not all that much higher than the shutt
>DA>would make an intercept pretty tight, and besides the optics are ob
>KH-11 is neither the latest nor the greatest "real-time" platform up there.
roland.dobbins@the-matrix.com (Roland Dobbins) keeps writing:
>Date: 2 Mar 93 08:44:00 GMT
>>>KH-11 is neither the latest nor the greatest "real-time" platform
>DA>The ADVANCED KH-11 is... we currently have 2-3 of them up.
>DA>OR, are you talking about Lacrosse or Aurora?
>Yes, among others . . .
>Although those two are primarily ELINT/SIGINT.
NO, they aren't... and WHY do you keep reposting these same messages
over again every day? How many replies do you want? This is about
the forth or fifth time I have seen it. What is the problem??
------------------------------
Date: 1 Mar 93 22:43:16 GMT
From: Jim Cook <jcook@epoch.com>
Subject: Why Apollo didn't continue?
Newsgroups: sci.space
In article 3qK@zoo.toronto.edu, henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <C33K2E.2yn@news.cso.uiuc.edu> car57812@uxa.cso.uiuc.edu (Charles Adam Rummel) writes:
>>They used the left-over Saturn parts to make Skylab, but was that because
>>they had run out of LEM/CSM and rovers or had too many Saturns, or...???
>
>All the Apollo and Saturn V hardware for Apollos 18-20 was on hand; the
>cancellations were for financial reasons, not lack of hardware. Going
>past Apollo 20 would have required re-starting the Saturn V production
>line. Somewhere around Apollo 22, I think, the spacecraft production lines
>would likewise have required restarting.
>
I have also seen quotes in two places (I'll find the references
if you want) that said they were also beginning to worry about "losing one."
This may be "sour grapes" or something similar, but the opinions were not
qualified as such.
Jim
---
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C. James Cook Epoch Systems, Inc.
508-836-4711x385 8 Technology Drive
JCook@Epoch.com Westboro, MA 01581
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End of Space Digest Volume 16 : Issue 270
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