Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_1/V16NO134.TXT

Internet Message Format | 1993-07-13 | 35KB

Date: Mon,  8 Feb 93 07:32:58
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #134
To: Space Digest Readers
Precedence: bulk


Space Digest                Mon,  8 Feb 93       Volume 16 : Issue 134

Today's Topics:
          An 'agitator' replies (was: Clinton's Promises...)
                         Challenger accident
                              Clementine
                      Cooling re-entry vehicles.
                             exotic fuels
         extreme responses to Challenger transcript (2 msgs)
                    Extreme response to transcript
                     FREE-ENERGY and other posts
                           Galileo update?
                         Handling Antimatter
                    Henry Spencer and other stamps
      Let's be more specific (was: Stupid Shut Cost arguements)
                              Mir Mirror
                     Payload Hit For Polar Orbit
                    Planetary Ephemeris Routines?
                           Solar sail Nits
                           Soyuz as an ACRV
                  Toutatis Captured by Radar Images
                         Units and Star Trek

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

Date: Thu, 4 Feb 1993 16:51:55 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: An 'agitator' replies (was: Clinton's Promises...)
Newsgroups: sci.space

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In <[e-mail]> [e-mail] (Doug Mohney) writes:

>However, there ain't no bucks yet for students, rabbis, priests, entertainers,
>blah-blah-blbah :)

Gosh, no wonder Eastern Airlines went out of business! :-)

American, United, Northwest Orient, etc. are *still* making money
carrying students, rabbis, preists, and other non-Buck Rogers types.


>Or are you meaning to tell me John Denver would sound better singing in orbit?

I don't know.  We'll find out.


>>When was the last time you saw someone on the Shuttle
>>doing work that actually required a scientist?

>Nope. Mr. PhD goes back to his company, writes up a nice paper about his
>experiment. Sooner or later, one of the papers comes up with a money-making
>process which needs zero G.

I guess I missed all the money-making processes that have come out
of NASA.  I also missed all those NASA mission specialists writing
papers.  They spend their time in space prepping satellites or
performing other people's experiments -- jobs that would be done
by technicians with a bachelor's or associate's degree on Earth.
NASA hires PhDs for these jobs because a) they get so many applicants,
they have to cut down the numbers somehow, and b) it fits the superhero
image of the astronaut NASA has constructed.


>You send up the handi-people AFTER you establish real ways to make money in
>orbit. But someone of note needs to establish the processes. And fix the
>experiments. If it were that easy, we'd send up trained monkeys.

"Trained monkey" is principle investigator's slang for astronaut!

How many Nobel Prize winners have you seen going into space on
the Shuttle?  How many brilliant young grad students, with new
insights into their field?  How many lunatic inventors on the
fringe of science with a crazy idea that just might work?



>>The best way to assure funding for SSTO launchers is to
>>stop NASA from stomping all over programs that might
>>compete with the Shuttle.

>That's a nice thought. But it does little to address the thrust of my point:
>Soyuz/Atlas is going to suck time, energy, and cash away from SSTO development.

No, Shuttle is going to suck time, energy, and cash away from
SSTO, and any other cookie jars NASA can manage to raid. (And
if it can't raid them, it will try to smash them.)


>You miss the point. We do not want to be subcontractors with the Russians.

Tough luck.  The world doesn't work that way anymore, kid.  Economic
nationalism is a dead end.  Future businesses will have to seek the
best-qualifed partners worldwide, if they want to stay in business.


>And perhaps you'd like to review MITI investments into advanced
>technologies? The Japanese aren't afraid to use government to invest
>in key technologies. Or maybe you've been asleep on the discussion of
>"industrial policy"?

Nope.  I've been awake while you and Mr. Clinton were sleeping.  MITI
and national industrial policy have been complete failures.  The
fifth-generation computer project is just one example.  The successes
Japan has had came depite MITI, not because of us.  Like the automobile
manufacturing, which MITI wanted to abolish because it was a "sunset
industry" and could never compete with Detroit.

The American frontier wasn't opened by a National Industrial Policy.

No frontier was ever opened by government bureaucrats.  And space
won't be, either.  It will be opened by the same kind of people
who have opened every frontier -- businessmen and soldiers, accompanied
by doctors, lawyers, scientists, engineers, technicians, workers,
teachers, artists, writers, and their children.


>>>Or, if you believe the press reports, BOUGHT a new Mir, for that matter.
>>They did.

>Oh really? Do tell. So when did they launch it and put their flag on it?

Does Macy's tell Gimbel's?


>>>As the saying goes, money talks, bullsh*t walks.
>>When Merrill Lynch talks, people listen.

>That's cute. So what's your point? Merrill Lynch isn't putting money into
>space.

Oh?  You think they keep people called "space analysts" on their staff
because of national industrial policy?

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

Date: Thu, 04 Feb 93 18:02:33 EST
From: Tom <[e-mail]>
Subject: Challenger accident

One of my thoughts:
>"Damned shame that it had to happen to the first civilian"

Mary Schafer points out:
>Just in the interests of accuracy, Christa McAuliffe was not "the
>first civilian".  [further elaboration]

Oh.  Thanks for setting me straight.  It was still one of my thoughts,
though; just happened to be wrong :-)

-Tommy Mac
------------------------------===========================================
Tom McWilliams; Average dude | The Freedom of our minds is what binds us
[e-mail]       | as a Nation; a People.  But the National
[phone] -or- 336-9591 | government tries to bind us, not free us.
------------------------------===========================================

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

Date: Thu, 4 Feb 1993 17:33:26 GMT
From: Henry Spencer <[e-mail]>
Subject: Clementine
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>What is the status of Clementine at this time (post-Clinton election)? I have
>heard rumors that all work has stopped since Nov. 3 on the lunar mission.
>
>I have also heard that Clementine is fully funded, and on track for a January,
>1994 launch to the Moon.

As of Making Orbit 93 (2.5 weeks ago), according to Jordin Kare (who is
working on the sensor side of Clementine while laser-propulsion funding
is nowhere to be had), funding is completely taken care of -- the mission
simply doesn't take that long or cost that much -- but schedule is a bit
of a worry.  If they miss the Jan 1994 launch, they can't use Geographos
for the asteroid part of the mission, and there is no other good asteroid
opportunity for a couple of years.

Other odds and ends about Clementine from my MO93 notes...

With launch in Jan 94, the nominal lunar mapping mission is two months,
(some time is eaten up in maneuvering and orbit adjustment), they boost
out of lunar orbit in May and pass by Geographos in August, just after
it's closest to Earth.

Launch is on a refurbished Titan II with a solid kick motor.  They'll
stay in the highly-elliptical transfer orbit for one or two revs, so
they can do orbit corrections cheaply at apogee.  (Spin-stabilized
solid stages are not very precise.)

The sensors are basically assorted optics, giving a 12-color map in
visible and near IR.  There's also a laser altimeter which will give
us a good lunar topographic map.  The orbit will be elliptical, with
500km altitude at the lowest point and 900km at the lunar poles.
Surface resolution at 500km, using the highest-resolution bands,
will be 125m.  Narrow strips will be imaged at rather higher resolution,
20m, but there won't be a continuous map at that resolution.

Although Clementine will greatly improve topographic and geochemical
knowledge of the lunar poles, none of the instruments can do a real
frozen-volatiles search.  For that you need neutron or gamma-ray
spectroscopy, and this is an optics mission.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Thu, 4 Feb 1993 17:25:03 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Cooling re-entry vehicles.
Newsgroups: sci.space

In <[e-mail]> [e-mail] writes:

>If you coat your vehicle's skin with water on-orbit and cause it to
>freeze, you have instant heat shielding.  You may have to be careful
>about the shape it takes on, but water tends to cling to surfaces by
>adhesion.

Gary Hudson is proposing a similar system for his Skyrocket
and Frequent Flyer (at least the leading edges) except that
he has the ice inside the metal skin.


>Given enough experimentation, you could probably make ice sculptures of
>lifting bodies (gliders) which would survive entry somewhat intact.

Unfortunately, pure ice is kind of brittle.  If chunks start
coming off during reentry, you're history.  During World War II,
the US Navy considered a scheme to build battleships out of ice.
They proposed lacing the ice with sawdust to increase its strength.

Also, gliders imply some kind of aerodynamic control surfaces.
How would you make them out of ice?  Wouldn't a ballistic capsule
be more appropriate?


>You could freeze your payload (film canisters, animals, people) in the
>center of the ice.

Brrr!

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

Date: Thu, 4 Feb 1993 18:23:20 GMT
From: Henry Spencer <[e-mail]>
Subject: exotic fuels
Newsgroups: sci.space

In article <[e-mail]> Graydon <[e-mail]> writes:
>Anyone doing anything on mon-atomic hydrogen as an escape fuel?

If there seemed to be any prospect of stabilizing atomic hydrogen in a
reasonable way, people would most assuredly be doing something about it.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 4 Feb 1993 17:07:47 GMT
From: Dillon Pyron <[e-mail]>
Subject: extreme responses to Challenger transcript
Newsgroups: sci.space,sci.astro,alt.privacy,comp.org.eff.talk

In article <[e-mail]>, [e-mail] (Tesuji) writes:
>As I look at the article, I would agree that it
>seems more likely than not to be concocted.
>(more from linguistic reasons than technical,
>although "2000 MPH" seems absurd to me, too.)
>
>But I think the issue here is an emotional one,
>not a technical one -- that is, even if the
>article were totally fabricated, that does
>not mean it necessarily is completely *false*.

If I suggested that you were a sadistic pediphile, is that not competely false
because it was totally fabricated?

>
>That is, could it have portrayed a possible outcome?

Which is not what you presented it as.  You present it as THE TRUTH, not just a
truth.
>
>If so, then in making decisions about redundancy,
>safety, escape strategies, NASA management style,
>this kind of "fiction" may make a wholer picture to
>balance parameters, financial *and* human cost.
>
>Sort of like televising executions, which most
>agree would be gruesome, some believe that it
>may lead to a fairer appraisal of constitutional
>safeguards.  It is sad that this is emotionally
>trying to the families and to the readers of the
>newsgroups.  I believe that on the balance, though,
>it leads to useful discussion.

You're still comparing lies to known facts.  This is like saying that watching
some actor get "killed" will reduce the murder rate!
>
>
>It has been amusing to see the extreme responses to the posting of the
>Challenger transcript; the burghers with their torches are storming the
>castle again.
>
>It is a wonder to me to see these outlandishly outrageous responses to things
>such as viral attacks: people suggest castration or execution to the perpetrators.
>When Len Rose was caught with a hacked copy of AT&Ts login.c, people suggested
>banning him from employment for life or other punishments that aren't
>even meted out for murderers in US society.
>
>It is especially ironic to see the cretins from Bell Labs heading up the
>peasants ready to torch me for my posting.  Bell Labs -- who help make
>widespread electronic communication possible.  It reminds me of the XEROX PARC
>corporate solicitation from employees for "security slogans";  I thought
>the best entry was the one by a friend of mine "If you want security,
>don't get a Xerox machine!".  It didn't win though.
>
>My posting was not libelous, obscene, or otherwise criminal.  Error and bad taste
>are protected freedoms in this country.  If you don't like my or any other
>postings, hit N.

Guess what.  It is criminal.  The "transcript" you published was originally
published in one of those grocery counter rags (_The Star_??).  Copyright
infringement.  And not libelous only because you can not libel (or slander) the
dead.  Error and bad taste are protected.  God knows I've exhibited both.  But
outright lies are another matter.
>
>-------------------------------------------------------------------------
>To find out more about the anon service, send mail to [e-mail].
>Due to the double-blind system, any replies to this message will be anonymized,
>and an anonymous id will be allocated automatically. You have been warned.
>Please report any problems, inappropriate use etc. to [e-mail].
>
And to hide behind anonymity makes it so much worse.  Be proud of what you do
or shove it up your ass.
--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
[phone] (when I'm here)     |
[phone] (when I'm home)     |"I wish I was dead" said Moxie.
[e-mail]          |"May your every wish come true" replied Spam
PADI DM-54909                     |      _Bored of the Rings_

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

Date: Thu, 4 Feb 1993 17:15:43 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: extreme responses to Challenger transcript
Newsgroups: sci.space,sci.astro,alt.privacy,comp.org.eff.talk

In <[e-mail]> [e-mail] (Tesuji) writes:

>X-Anon-To:sci.space,sci.astro,alt.privacy,comp.org.eff.talk

>As I look at the article, I would agree that it
>seems more likely than not to be concocted.

To put it mildly.  This is rather like saying that stories of Elvis
being seen on Pluto are "more likely than not to be concocted".

>But I think the issue here is an emotional one,
>not a technical one -- that is, even if the
>article were totally fabricated, that does
>not mean it necessarily is completely *false*.

>That is, could it have portrayed a possible outcome?

Yes, "possible" in the sense that it's "possible" that Challenger was
destroyed by an avenging angel who came down and ripped a hole in its
side.  Likely?  Not even close.

>It has been amusing to see the extreme responses to the posting of the
>Challenger transcript; the burghers with their torches are storming the
>castle again.

Odd.  I don't see anything extreme about someone being called an idiot
for doing something idiotic.  You are an idiot.  See?  Not extreme at
all.

>My posting was not libelous, obscene, or otherwise criminal.  Error and bad taste
>are protected freedoms in this country.  If you don't like my or any other
>postings, hit N.

If you don't have the principles to stand by what you post (as other
than an anonymous loudmouth), hit 'the road'.  And if you really need
'attention' this bad, hit 'the couch' -- perhaps the good doctor can
help you.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: Thu, 04 Feb 93 18:25:15 EST
From: Tom <[e-mail]>
Subject: Extreme response to transcript

Tesuji sez;
>>It has been amusing to see the extreme responses to the posting of the
>>Challenger transcript; the burghers with their torches are storming the
>>castle again.

Tarl Neustaedter replies;
>Had you simply posted that fabricated transcript, you would have been
>flamed for posting something inappropriate and frankly libelious (yes,
>you accuse NASA of a coverup. That's libelious). And it would have ended.

Just a nit:  I don't think libel against public figures (politicians)
or gov. agencies is possible (a legal non-issue) because people gripe
and gripe and gripe about them all the time.  So, the logic seems to
be, we don't want to tie up the courts, and you can't really damamge
them, since everyone should know that the gripes are just gripes, so
libel against them is a futile charge.  Similar to inability to sue
gov. agencies.

Besides, NASA may have covered something up, and libel only deals with
falsehoods.

>The extreme reactions come from the fact that you don't have the BALLS
>to even post it under your own name, you feel you have to hide behind
>an anonymous posting service.

Hmm.  I would have guessed that the reactions are due to the emotional
weight of the situation.  I do think it's disturbing that Tesuji,
whoever s/he/it is, found those primarily emotional responses 'amusing'.

If I had the 'play-with-people' attitude that Tsuji appears to have,
I'd hide too.

-Tommy Mac
------------------------------===========================================
Tom McWilliams; Average dude | The Freedom of our minds is what binds us
[e-mail]       | as a Nation; a People.  But the National
[phone] -or- 336-9591 | government tries to bind us, not free us.
------------------------------===========================================

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

Date: Thu, 04 Feb 93 18:13:59 EST
From: Tom <[e-mail]>
Subject: FREE-ENERGY and other posts

>                           FREE-ENERGY TECHNOLOGY
>                      by Robert E. McElwaine, Physicist

[lots of stuff that you've already seen or ignored several times]

Maybe if we gave this kind of stuff a FAQ, we wouldn't keep seeing it
over and over.  Y'know, like "SPACE FAQ 145:  Really outlandish stuff that
the authors insist is absolutely true."  I've heard that a lot
of scientific journals do the same sort of thing with submissions of
dubious value, just so the people will accept that, yes, their voice
has been heard.

-Tommy Mac
------------------------------===========================================
Tom McWilliams; Average dude | The Freedom of our minds is what binds us
[e-mail]       | as a Nation; a People.  But the National
[phone] -or- 336-9591 | government tries to bind us, not free us.
------------------------------===========================================

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

Date: Thu, 4 Feb 1993 17:06:47 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Galileo update?
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Bruce Bowen) writes:

>From article <[e-mail]>, by [e-mail] (Ron Baalke):
>> The recent hammerings have not opened the antenna.  The first hammering
>> attempt turned the ballscrew an additional full rotation, but it has
>> not budged since.  Despite 13,000+ hammerings at different frequencies
>> and at various antenna temperatures, the ribs are still stuck.

> Is it possible to reverse the motor and retract the antenna?  Maybe reversing it
>will relieve whatever is holding it closed and then allow it to open.

I believe the relay which would have allowed applying power to the
motor to reverse it was used for something else.  One of those
consequences of limited weight and space budgets and making a change
to something at the last minute, I expect.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: Thu, 4 Feb 1993 18:27:41 GMT
From: Henry Spencer <[e-mail]>
Subject: Handling Antimatter
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Hugh Emberson) writes:
>... I'm no expert, but I think there would be little or no
>radiation release from a Nerva-style nuclear thermal rocket...

Unfortunately, not so.  If you run fluid through a reactor core, the fluid
ends up with small amounts of things like fission products in it.  This is
especially true if you're running the fluid through at high speed in a
reactor which is constrained to be very lightweight.

>Nervas were tested, does anyone have any figures for the amount of
>radiation (or radioactive materials) released into the environment?

I don't have numbers... but I do know that those tests would not be
considered acceptable today.  The people working on nuclear-thermal
propulsion are assuming that they will need, at the very least, good
exhaust scrubbers for their testbed setup.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 04 Feb 93 19:05:42 EST
From: Tom <[e-mail]>
Subject: Henry Spencer and other stamps

>>|> | > |>Does anyone know why Henry Spencer has not posted recently?
>>|> | > Perhaps he is on vacation - with Elvis?
>>|> He's *ba-a-a-a-ck-k-k...*
>>|> :) And we're all glad!
>>who's back ?
>>Elvis ?
>Is there a Henry Spencer stamp yet?  Which Henry picture did they use?  ;-)

No, but I just went down to the post office to get some stamps, and, being
tired of ducks, asked what they had.

I got this cool set of 'Space Fantasy' stamps.  The look pretty good.
What little writing is on them looks like the machine-readable stuff
on the bottom of a check, and they are very colorful.  Rockets, Jet-packs,
Jetson-style housing, ringed planets, and such.  I highly reccommend
using stamps for sending letters, BTW.

But Henry Spencer wasn't anywhere on them! :-)

-Tommy Mac
------------------------------===========================================
Tom McWilliams; Average dude | The Freedom of our minds is what binds us
[e-mail]       | as a Nation; a People.  But the National
[phone] -or- 336-9591 | government tries to bind us, not free us.
------------------------------===========================================

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

Date: Thu, 4 Feb 1993 17:43:58 GMT
From: Henry Spencer <[e-mail]>
Subject: Let's be more specific (was: Stupid Shut Cost arguements)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>I heard they used oak. Dry wood char is a fairly good insulator in an
>oxygen poor environment... 20% excess oxygen is something
>else, and that's what you've got during re-entry, a hot high speed flow
>of oxygen rich gas. If you can protect the wood from direct oxygen
>exposure, you may have something.

The Chinese use treated oak, not plain wood.  Not sure what chemicals
they use for treatment.  (I'd be tempted to try some sort of carbonate,
which would release CO2 on thermal breakdown.)

>I think even balsa wood is heavier
>than the Shuttle tiles, however.

Depends on what kind of specs you are trying to meet.  It's important to
realize that winged and (near-)ballistic reentry are two different regimes.
Winged reentry involves somewhat lower peak heat loads but much higher
total heat loads.  Neither ablation nor fluid-dump cooling is particularly
well-suited to winged reentry; you need a refractory outer surface that's
insulated from the interior.  For a semi-ballistic reentry, it's a lot
harder to do things that way, and much easier to use ablative or liquid-
cooled heatshields.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 4 Feb 93 16:39:46 GMT
From: "David M. Faubert" <[e-mail]>
Subject: Mir Mirror
Newsgroups: sci.space

Hi,

On the radio this morning I heard that the Russian mirror experiment could
be seen in the west from Vancouver, where I am. I went outside and, sure
enough, there was this extremelely bright light in the west. By extremely,
I mean around magnitude -5 I suppose. It was flickering slightly and it
was slightly yellow, which is what one would expect from a light outside
the atmosphere that low on the horizon.

Did anyone else see it? I would like to have some confirmation that the
thing I saw was the mirror and not something else like another UFO.



Dave

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

Date: Thu, 4 Feb 93 15:11:09 PST
From: "UTADNX::UTDSSA::GREER"@utspan.span.nasa.gov
Subject: Payload Hit For Polar Orbit

In Space Digest V16 #112,
Dave Michelson <[e-mail]> writes:

>In article <[e-mail]> [e-mail] writes:
>>
>>This myth keeps coming up & it's not correct.  You take only an order 15%
>>payload hit to launch to Mir's inclination from the Cape.

>On a related topic...

>Recently, there has been much talk about launching satellites into polar
>orbit from near the poles (Poker Flats, Alaska or Ft. Churchill, Manitoba)
>in order to maximize the payload to orbit.  I checked out my usual sources
>(Introduction to Space Dynamics and Fundamentals of Astrodynamics) but
>couldn't find anything concerning the effect of launch site latitude
>and desired orbit inclination on the maximum payload...

>How big is the "payload hit" if one were to launch into polar orbit from
>the equator rather than from, say, the North Pole or perhaps the Arctic
>Circle?  I wouldn't have thought it was that big but some people give the
>impression that it is.

We have everything from rocketry to orbital mechanics in our library, but
I was still unable to find anything specifically addressing this question.
However, we can get a good estimate by examining the physics of it.

We know that kinetic energy varies with the square of the velocity.  Orbital
velocity at 300 km altitude is about 7700 meters/second, while the velocity of
the surface of the Earth at the equator is about 460 m/s.  So, roughly, we can
say that the required change in velocity for a rocket launched at the equator
of a rotating Earth is only 7240 m/s instead of 7700 m/s, which gives us an
energy bonus of almost 12% for equatorial launch.  The Earth's surface
velocity due to rotation varies with the cosine of the latitude, so at the
Cape, it is about 400 m/s.

Launching into a polar orbit from the Pole would require a delta-v of 7700 m/s,
but launching due North from the equator would put the vehicle into an 86.5
degree orbit, because of the 460 m/s eastward velocity boost.  Correcting for
this would only result in a .35% energy penalty over the due North case.

By this method, a retrograde equatorial orbit would have a 21% energy penalty
over one in the opposite direction.  It is important to note, however, that
the energy penalty is probably somewhat less than the payload penalty, since
the extra energy requires extra fuel, which adds mass which requires extra
fuel, and so on.  I'm no rocket scientist, so maybe someone else could fill
in the rest of this question.

>Dave Michelson                             University of British Columbia
>[e-mail]                                  Antenna Laboratory

_____________
Dale M. Greer, whose opinions are not to be confused with those of the
Center for Space Sciences, U.T. at Dallas, UTSPAN::UTADNX::UTDSSA::GREER
"Let machines multiply, doing the work of many,
                     But let the people have no use for them." - Lao Tzu

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

Date: Thu, 4 Feb 1993 18:00:18 GMT
From: Henry Spencer <[e-mail]>
Subject: Planetary Ephemeris Routines?
Newsgroups: sci.space,sci.astro,comp.lang.c

In article <[e-mail]> [e-mail] (Jonathan Young) writes:
>What I need are some routines which can calculate planet positions
>with accuracy more important than speed...

Have you checked Jan Meeus's book "Astronomical Algorithms"?  My copy
isn't handy, but this is exactly the sort of thing he goes into loving
detail about.  I believe the code is available on floppy.

(He does balk at providing a maximum-accuracy algorithm for the Moon,
though.  He gives a medium-accuracy one.  Predicting the Moon's position
really accurately is *hideously* complex.)
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 4 Feb 1993 17:09:29 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Solar sail Nits
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Tom) writes:


>>>Yep ... you simply turn it around and use it to capture the *outward* solar
>>>wind of your destination star to slow you down.

>>Solar sails do NOT use the solar wind.  They run on light pressure.

>Further nit:  If light has momentum and protons have a wavelength,
>how do you classify one as wind and not the other?  They are both
>"stuff emitted from the sun at supersonic velocities" after all.

>(Yes, I know the light gives greater momentum, and that the def. of
>solar wind is "Protons from the sun".  But it is a rather arbitrary
>def., isn't it?)

Can you say "rest mass"?

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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Date: Thu, 4 Feb 1993 17:49:59 GMT
From: Henry Spencer <[e-mail]>
Subject: Soyuz as an ACRV
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Under the terms of the Launch Services Purchase Act, NASA is prohibited
>from orbiting non-shuttle-specific payloads...

And who determines what is shuttle-specific?  (Hint:  four letters, starts
with "N". :-))

They can find some excuse.  They've had practice.  They were supposed to
kick all non-shuttle-specific commercial payloads off after Challenger,
but there was an amazing list of exceptions.  I still haven't figured
out how they managed to keep the Geostar birds on the shuttle manifest
(those were straight commercial comsats except for some details of the
electronics); I don't think I could have done it with a straight face.

After all, it's not as if the space station was particularly shuttle-
specific...
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Thu, 4 Feb 1993 18:12:03 GMT
From: Henry Spencer <[e-mail]>
Subject: Toutatis Captured by Radar Images
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> <[e-mail]> writes:
>Has anyone an idea to which class "Toutatis" belongs? Is it a S-type-
>asteroid like "Gaspra"? ...

Don't be too quick to declare Gaspra an S-type.  The latest word is that
its magnetic field is too strong for it to be anything but nickel-iron
inside, regardless of what the surface looks like.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 04 Feb 93 17:54:12 EST
From: Tom <[e-mail]>
Subject: Units and Star Trek

>>What is 'warp', anyway?

>Well, since Warp 1 is c, the speed of light, it should take a ship traveling
>to a planet 60 light years away 60 years. Pretty basic...

Gee, we don't cover super-luminal transformations in any classes here
at MSU, but I'm sure there's some effect...or were we talking about
how long it takes from the destination/departure point-of-view? :-)

-Tommy Mac
------------------------------===========================================
Tom McWilliams; Average dude | The Freedom of our minds is what binds us
[e-mail]       | as a Nation; a People.  But the National
[phone] -or- 336-9591 | government tries to bind us, not free us.
------------------------------===========================================

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End of Space Digest Volume 16 : Issue 134
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