Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_9/v16no894.txt

Text File | 1993-07-20 | 34KB | 783 lines

Space Digest                Tue, 20 Jul 93       Volume 16 : Issue 894

Today's Topics:
                CTAS, GPS, and Collision alert ideas..
                       DC-X thermal protection
      Electronic Journal of the ASA (EJASA) - July 1993 [Part 2]
              GPS in space (was Re: DC-1 & BDB) (2 msgs)
                   Hubble, Why the hurry? (3 msgs)
                         MOON CABLE (2 msgs)
                     Saturn stage names (2 msgs)
                           SETI information
        WATW Orbit (was Re: GPS in space (was Re: DC-1 & BDB)
                   Why are meteor showers seasonal?

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

Date: Mon, 19 Jul 1993 13:37:48 GMT
From: "David L. Jones" <[e-mail]>
Subject: CTAS, GPS, and Collision alert ideas..
Newsgroups: sci.space

[e-mail] wrote:
> I have not been on ina  bit, but have an idea, that migth already have been
> thought off. Maybe as a primary system or secondary backup or helper system..
>
> Wht not have satellites that combined with a transponder on a airlinerr, can
> keep track of airliners no matter where they are, combined with a system of
> this, you can program it so that when two aurliners are to close (mile or so
> out), the system can send a "collision alert" message to the airliners..
>

Critical delays in getting and responding to info like this limit the
distance between planes to 5 miles already ( and that for planes travelling
in roughly the same direction.  Head-on the planes converge at one-mile
every 3 seconds or so).  Your speed-of-light delay in the system may be as
much as one quarter second for a GEO satellite.

In any case this situation arises only near airports, where it is much more
easily and cheaply handled by ground radar.

--
| [e-mail] -----Dave Jones Northern Telecom Rochester NY|
|...Home of the week-old newsfeed.  Better never than late!.........|
|-------(actually its improving...)---------------------------------|
| Vote for rec.sports.australian-rules-frisbee ---------------------|
|-------------------------------------------------------------------|

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

Date: Mon, 19 Jul 1993 19:27:55 GMT
From: Henry Spencer <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>Is this the remnant of the silly USAF requirement
>>that the STS be able to  fly  1,800 miles cross range.
>
>It's not a silly requirement if you want to fly polar missions and can't
>land just anywhere. Also, I don't know DC's crossrange but it is in the
>same ballpark as Shuttle.

It *is* a silly requirement, for an SSTO.  Making a landing after a
single polar orbit is no big deal, assuming you aren't stupid enough to
launch from the West Coast (in which case there are no suitable landing
areas, just a lot of ocean).  Life does get more difficult if pieces
fall off your craft on the way up, as with the shuttle, since you need
somewhere to drop them.  But an SSTO doesn't have that problem.

McDD evidently decided that it was worth going to some lengths to achieve
a lot of cross-range.  It wasn't in the specs; GD's SSTO proposal was a
classic Bono-type design with very little cross-range.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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

Date: Mon, 19 Jul 1993 18:15:10 GMT
From: Larry Klaes <[e-mail]>
Subject: Electronic Journal of the ASA (EJASA) - July 1993 [Part 2]
Newsgroups: sci.astro,sci.space,sci.misc,sci.geo.geology,alt.sci.planetary

    whether spiral arms were really physical or merely statistical.  As
    he took questions from the audience, another professor mentioned that
    he had also done something like this, but had included parameters to
    simulate interstellar dust and gas.  The speaker had simplified his by
    not doing so.  After the discussion they arranged to speak together
    about this.

        Once the education sessions were complete I headed for the
    Pavilion tent.  This is where all the exhibits were located.  There
    were companies promoting their services or equipment.  Want an
    automated small aperture telescope?  No problem.  Need observation
    data from NASA?  They have got you covered.  Hubble Space Telescope
    (HST) information?  Lots.  Want to join the AAS?  You bet!

        I found technical book companies offering how to use fractals in
    astronomy.  Several observatories had displays promoting their current
    research projects.  Kitt Peak had a display on their latest telescope
    construction.  The submillimeter array had brochures available for
    interested attendees.  The replacement for the Kuiper Airborne
    Observatory (KAO) had a cutaway diagram to view.  All of these were
    to be found around the perimeter and down the middle of the tent.

        As I wandered amidst all this I found research projects being done
    by astronomers.  Several of the undergraduate astronomy students from
    ASU had their names on some projects, including some of our SAC members.
    At least one of my old astronomy professors, Dr. Per Aannestad, was
    manning his display to discuss his project with others on atmospheres
    around white dwarf stars to explain the strange lines observed in
    their spectra.  These spectra apparently did not fit into the current
    theories, but they were successful at eliminating this possibility
    to explain it away.

        I also ran into a fellow from New York who had developed a way
    for students to get a real feel for parallax.  Using CCD cameras in
    different locations across the country, say New York and Kansas,
    simultaneous observations of a planetoid would be arranged for
    students.  They would process their results and mail the images to
    each other.  By noting the different stellar positions in the back-
    ground and measuring the planetoid's displacement, the parallax and
    its distance from Earth could be determined.  His goal is to make
    the results available in real time in the near future.

        He also proposed that students could use polar-orbiting satellites
    to accomplish the parallax test.  By using CCD cameras on 35mm lenses,
    they could take several minute exposures and observe the same satellites
    from several kilometers apart.  The trails would appear to pass over
    different stars and a distance could be determined.

        As we discussed these projects he noticed my badge and mentioned
    that he had heard of our club.  He asked if we put out a database of
    viewable objects.  I confirmed this and we then proceeded to discuss
    our project in detail.  He was impressed by our efforts and suggested
    that we keep up the good work.  So it looks like we are notorious,
    fellow SAC members.

        All in all I (Paul) had a good time.  If I had a chance to do this
    again, I would work fewer hours so I could attend random presentations
    in differing sessions.  This meeting is not for the novice.  In some
    cases, the details of what was covered were beyond my understanding,
    but it exposed me to new directions for further astronomical learning.

        Related EJASA Article -

        "The 179th Meeting of the American Astronomical Society (AAS):
         A Volunteer's View", by Ingrid Siegert-Tanghe - April 1992

        About the Authors -

        Paul Dickson has been a member of SAC since 1988 and has been the
    Editor of SAC's SACNews for more than three years.  Paul is currently
    a student at Arizona State University and works for Bull HN, Inc.
    Paul has contributed a number of articles from SAC to the EJASA.
    His net address may be found at the beginning of this article.

        Mike Willmoth has been a member of the Saguaro Astronomy Club
    (SAC) since 1978.  Currently, Mike is with the Arizona Department of
    Transportation as a systems engineer, helps put on science fiction
    conventions to advance the public's education about the future of
    space travel, and is creating a video history of SAC's meetings so
    that others may benefit from its educational offerings.


      THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC

                          July 1993 - Vol. 4, No. 12

                           Copyright (c) 1993 - ASA

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

Date: 19 Jul 1993 21:02:38 GMT
From: Doug Mohney <[e-mail]>
Subject: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

In article <226tm0$[e-mail]>, [e-mail] (Pat) writes:

>Depends on who you talk to.  The russians and japanese have talked about
>70 plus inclination orbits.

Sure. They are. WE aren't.  It's taken NASA quite a leap to even consider 51.6.

>>So?  You aren't going to be launching hardware til 1998 at the earliest under
>>anyone's estimates, with the most stuff launched between 1998-2002. Back to the
>>drawing board pat.
>I don't think an Ariane 4 could meet launch requirements for construction
>flights.

Ariane 4 could be used for grocery flights.

>  And Ariane 5 is not yet in anything approaching operational
>status.   If you are proposing using Ariane 5 for construction flights
>it would be far cheaper to subsidize  energiya certification.

How figure?  Political stability is much better within ESA than ex-Russia.

>so what you must be saying is that ariane  could be used to help support
>logistics needs for SSF.  Possibly,  if they develope an auto docking
>system and if they can meet the materials flow requirements.

They could just as easily write a check to the Russians for auto-docking or
develop their own.  Not that tough.


>>Political considerations (translation:  The Chinese are rude to their own
>>people) make me doubt that we'll be buying or encouraging the Chinese to sign
>>up in the short term.
>
>The chinese government may change its ways,

May?  Boy, that's really assuring, Pat.  Why don't you try to encourage the
U.S. goverment to spend taxpayer dollars for the butchers of Bejing and see
just how much fallout occurs?

>  AND  they do have
>Most Favored Nation Trading status.  They aren't that much
>on the outs,

Oh really?  Why are there 50 boatloads of refugees trying to make it to our
shores? (Hm, because they don't like the cold of Canada? :)

> besides,  the Japanese may contract with CHina
>for a Logistics run or two.  they have no problem with what the
>chinese government is up to.

The Japanese just changed governments.  Nobody knows what they're going to do
anywhere...

>The performance hit is  tough on the shuttle,  but  it's not that bad
>on our ELV fleet.

Nobody at NASA is working numbers for the shuttle past 51.6. Sorry, them
there's the facts.

>51  and 65 are not bad orbits,  and the japanese can hit them,
>they just take a performance hit.

Forgive me, but I have little sympathy for the Japanese :)

>Besides the H-2 is nowhere near  flight ready  so we don't exactly have
>to take a big risk  if they can't optimally reach it.  Who knows when
>they'll actually be operational.

Pat, are you playing Cuomo?  First you want the Japanese, now you don't really
care if they show up so who cares when they're operational? C'mon, even Bill
clinton doesn't change his mind about breakfast cereals that quickly...

>Well,  I guess the contract requirements  should include purchase of
>3-4 years supplies of Soyuz's  up front.

You guess?  I doubt Congress will ever fund buying that many capsules up front.

>And in case you didn't notice,  NASA has  not only a 14 Billion dollar
>budget,

Yah, so?

>  but a 2.1 Billion dollar SSF construction budget.  If they can't
>re-program this money around to reduce risk,  they shouldn't
>be handling any of it.

Pat, so what piece of hardwares do you put off buying THIS year in order to
have your stockpile of Soyuzes?  Let's do some math:

    2 Soyuz capsules * 2 = 4 capsules/year * $10 mil/capsule = $40 mil/year

Now, you want to go out and triple that on a one time basis.  Say $120 mil.
So who do you screw, what projects do you set back for the $80 mil needed
"up front"?

>Also, if you haven't noticed, the russians have gone through now 2
>revolutions essentially  (Perestroika, Yeltsinisms)  THey are still
>meeting contract obligations  to the europeans for Natural Gas and Oil.

No, actually, they've gone through one near-coup, with Yeltsin coming out on
top.  The possiblity exists of a nationalistic coup.  It's why the Ukrainians
want to hold on to nuclear weapons on their soil... just in case.

As for oil and gas contracts... certainly they're pumping, but ask the
bureaucrat in Moscow or the warlord,errr Boss in Siberia as to who should own
and control the oil... you'd get two very different answers...

>>>The rpimary onjective of SSF is to enrich a bunch of contractors.
>>Pat, if that's the case, than you should lobby to kill it outright, rather than
>>engaging in the mental masterbation of putting SSF at different orbits.
>You go fight the corporate lobbyists.  I have better things to do
>with my day.

Fine Pat. You're part of the problem (apathy) than a part of the solution :)

>I recognize that SSF will be funded through FInal construction.
>I am just discussing realistic options about where it may fly.

No, you're playing what-if games and seeing what sticks.  Tsk.

>I am sure the contractors would prefer that it never fly.  that
>way they don't have to explain any failures.

That's a crappy assumption based upon your regurgitation of Sherzer's hatred to
nearly all things NASA.

>>Sure, but then the nickle-and-dimers will shut down Shuttle because, after all,
>>it's Just Too Expensive and where does that leave us?  Dependent on the
>>Russians and hoping that they stay our friends.
>
>Well, If the STS is dropped due to Cost,  (An idea i have no serious
>problme with)  I would hope  that some work would be done at
>Using our ELV fleet  for station logistics.

Pat, once you play the cost game, you lose because the Russians are currently
the cheapest on the block.  Or are we going to make the same mistakes with
closing down Apollo before we started Shuttle?

>As you posted,  NASA is contracting for studies at Using Soyus on
>Titan and Delta ( or was it Atlas and Delta)...

No launch vehicles were specifically spec'd, only companies looking at
feasibilities using their current products.

>Besides,  by the time SSF  gets flying,  DC-1  may well be operational.

SSF has more guaranteed money right now than DC-anything.

Maybe you'd better revisit your IFs again, humm?

>It is only your supposition that we would have one years supply of
>ACRVs.  If NASA is that bad at managing,  what makes you
>think they'll even deliver a station.

Gosh Pat, I think they're bound by fiscal constraints and a set of political
pressures which will force them into potentially compromising positions.

It isn't that NASA is "that bad" but that that A) There isn't the money
magically available for reprogramming which you'd like to think and B) Nobody
every accused a bureaucrazy of doing the "right" thing.

>I myself doubt  that they will ever deliver a station,  but
>for the purposes of selecting an orbital  inclination,   one
>must assume there will be a station.

"Pat, for the purposes of picking an arguement, will assume something exists
which he doesn't believe in."

OK, thank you pat.

>>Government does not operate like a corporation.  The National Interest
>>sometimes requires that goverment take a more expensive route to preserve
>>capabilities which may be of vital interest to the nation.

>You mean like the Saturn V?  or Domestic Oil production?
>or synthetic fuels?  or Energy COnservation?

Pat, stop drooling.  The key phrase is "sometimes."  The National Petrolium
Reserve worked as it should have.

>>Because the RUSSIANS have some questions as to their reliability for suppliers.
>>And it is a certain fact that Russian prices will go up somewhat.  How much?
>>Who knows?
>All the more reason to snap up a big supply of Soyuz capsules now,
>while the price is cheap.

Sure, get Congress, who has already set a magical cap on SSF spending per year,
to allocate another $80-120 million to buy up Soyuz capsules like so much
laundry soap.

Fat chance.



     January 1993 - John Scully embraces Bill Clinton.
     July 1993    - Apple Computer lays off 2500 workers, posts $188
            million dollar loss.

  -- >                  [e-mail]                        < --

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

Date: 19 Jul 1993 22:12:54 GMT
From: George William Herbert <[e-mail]>
Subject: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Ariane 4 could be used for grocery flights.

...but it would be a mistake to do so.  Arianne 4 missions these days are
running annoyingly close to $90m/launch, with the equivalent payload Atlas
only $45 million to $50 million, the Chinese launchers in the 6-7 ton to LEO
class at about $18-25 million, and the Soyuz at down around $10 million if
you buy now.

The Chinese and Russian options may not be stable in the long run, but
the Atlas is about 50% cheaper.  It's reliability is low right now, but
I have confidence that the Centaur problems will be overcome and it will
be back to 85%+ reliability shortly.

-george william herbert
Retro Aerospace

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

Date: 19 Jul 93 21:17:40 GMT
From: Peter Monta <[e-mail]>
Subject: Hubble, Why the hurry?
Newsgroups: sci.astro,sci.space

[e-mail] (Bob Myers) writes:

> What were the original expectations for the service life of these
> gyros?  Has their design been modified for improved reliability?

Boston Globe had a recent article on the repair mission; the number
that caught my eye was the 15-year (!) gyro design lifetime.

So, naive question, but why aren't laser-interferometric gyros used?
With good diode lasers available, plasma-tube lifetime/fragility
would be moot.

Peter Monta   [e-mail]
MIT Advanced Television Research Program

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

Date: Mon, 19 Jul 1993 21:49:19 GMT
From: Henry Spencer <[e-mail]>
Subject: Hubble, Why the hurry?
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Peter Monta) writes:
>So, naive question, but why aren't laser-interferometric gyros used?
>With good diode lasers available, plasma-tube lifetime/fragility
>would be moot.

I believe diode lasers don't produce a sufficiently clean output to be
used in orthodox laser gyros yet.  And laser gyros qualified for combat
aircraft don't need much improvement in durability to be good enough
(in that department) for spaceflight.

However, to address the general point:  remember that Hubble is a 1970s
design, and one that hit some cost crunches which limited development of
new subsystems.  I'm told that the Hubble gyros weren't particularly
advanced even by the standards of the time; there are better mechanical
gyros, never mind laser types.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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

Date: Mon, 19 Jul 1993 22:54:54 GMT
From: [e-mail]
Subject: Hubble, Why the hurry?
Newsgroups: sci.astro,sci.space

In article <[e-mail]>, [e-mail] (Peter Monta) writes:
> [e-mail] (Bob Myers) writes:
>
>> What were the original expectations for the service life of these
>> gyros?  Has their design been modified for improved reliability?
>
> Boston Globe had a recent article on the repair mission; the number
> that caught my eye was the 15-year (!) gyro design lifetime.
>
> So, naive question, but why aren't laser-interferometric gyros used?
> With good diode lasers available, plasma-tube lifetime/fragility
> would be moot.
>

But have they been space tested?  Where they around in the mid 70s
when HST was being designed?  I don't think so.


____________________________________________________________________________
Robert C Dempsey                                      [phone]
STScI-PODPS                                           3700 San Martin Dr.
                                                      Baltimore, MD 21218

      o   \ o /  _ o         __|    \ /     |__        o _  \ o /   o
     /|\    |     /\   ___\o   \o    |    o/    o/__   /\     |    /|\
     / \   / \   | \  /)  |    ( \  /o\  / )    |  (\  / |   / \   / \
____________________________________________________________________________

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

Date: Mon, 19 Jul 1993 19:19:26 GMT
From: Henry Spencer <[e-mail]>
Subject: MOON CABLE
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steven R. Garman) writes:
>The trouble with building a moon cable is simple.  There is no known
>material which could support its ownweight over that distance.  For
>example, how much steel cable could you lower from a mystical floating
>platform before the weight of the cable broke the cable.  The answer is ...
>not nearly enough to dangle a cable from space.  Even the strongest
>materials which can be theorized could only support about a fifty mile long
>cable...

Sorry, not true.  The moon cable *is* a dumb idea, but you're grossly
underestimating what can be done with cables.  In particular, a cable
between Earth's surface and Clarke orbit (40000km) is well within the
theoretical strength of materials, and is not that far from materials
that can be demonstrated in the lab today.

There are two key facts you've overlooked.  The first is that steel is
not a good material for this; it's really pretty weak.  Commercially-
available carbon fiber already has ultimate strength in excess of one
million psi, and the comparison is still more striking if you figure
in its much lower density.  (One million psi means a cable about the
thickness of your torso that could lift an aircraft carrier.)  (With no
safety margin, mind you... best watch from a good safe distance. :-))
Even Kevlar is far better than steel for this.

The second is that the cable doesn't have to be of uniform cross-section.
Tapering the cable, to make it stronger at the top and lighter at the
bottom, is crucial to making such schemes work.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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

Date: Mon, 19 Jul 1993 19:39:36 GMT
From: Henry Spencer <[e-mail]>
Subject: MOON CABLE
Newsgroups: sci.space

In article <22eeh8$[e-mail]> [e-mail] (Lab Master) writes:
>The main "expense" in putting something in orbit is energy, right?

Well, no -- the biggest cost is the incredible amounts of manpower that
go into the organizations that currently do spaceflight.  Second is the
loss of or wear-and-tear on hardware.  Energy is a distant third.

>Wouldn't running something up a skyhook take just as much energy as
>launching it with a rocket?  If so, what's the big advantage of a skyhook?

The energy put into the payload is the same.  But you don't waste any
energy on expended rocket stages or heat and turbulence in exhaust gas.
The savings are considerable.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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

Date: 19 JUL 93 15:31:12
From: Gary Hughes - VMS Development <[e-mail]>
Subject: Saturn stage names
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Dave Michelson) writes...
>In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>
>>If you think this is bad, consider that "Saturn C-3" could refer to any
>>of three or four totally different launchers, depending on the date.
>>There were *lots* of paper designs for Saturns, all the way from the
>>one-stage Saturn I (which did in fact fly) to the Saturn C-8 (with
>>eight F-1s in the first stage, practically a Nova, which didn't).
>
>Consider also that the Saturn I was originally called the Juno V.  It was
>supposed to use either four E-1 engines or one F-1 engine but neither were
>available (was the E-1 ever brought to production?) so von Braun decided
>to cluster eight upgraded Jupiter S3-D engines which were renamed H-1...

The Juno V name originally applied to what became the Saturn S-I stage. The
Juno name was dropped before upper stages were defined.

The E-1 never went to production (I don't think it got off the drawing board).
I don't recall ever seeing anything to suggest the F-1 was a serious contender
for the S-I stage. Von Braun's team wanted to use 4 E-1s, but Rocketdyne
countered with the suggestion of using 8 H-1s. The H-1 had been an inhouse
project to redesign the S-3D/MA3/MB-3 series of engines based on operational
experience. The major changes were moving the turbopump to below the gimbal
block and to simplify the ignition sequence.

gary

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

Date: Mon, 19 Jul 1993 21:56:54 GMT
From: Dave Michelson <[e-mail]>
Subject: Saturn stage names
Newsgroups: sci.space

In article <[e-mail]> [e-mail]
(Gary Hughes - VMS Development) writes:
>>
>>Consider also that the Saturn I was originally called the Juno V.  It was
>>supposed to use either four E-1 engines or one F-1 engine but neither were
>>available (was the E-1 ever brought to production?) so von Braun decided
>>to cluster eight upgraded Jupiter S3-D engines which were renamed H-1...
>
>The Juno V name originally applied to what became the Saturn S-I stage. The
>Juno name was dropped before upper stages were defined.

The name change occurred when the development program was formally approved
in August 1958.

>The E-1 never went to production (I don't think it got off the drawing board).
>I don't recall ever seeing anything to suggest the F-1 was a serious contender
>for the S-I stage.

Well, the issue was raised by both Frank Winter and Willy Ley in their
respective histories.  The E-1 and F-1 were both at comparable stages
of development but wouldn't be ready for quite a while...  At the same
time, there were apparently *many* rocket engineers who strongly
adhered to the belief in "one big engine", as an eyewitness to these
events recently confirmed.  von Braun "made himself the spokesman" for the
opposing group that promoted clustering of smaller, more reliable engines if
they were available off the shelf rather than wait around for new engines to be
developed.  The use of clusters of Redstone (and a Jupiter) tankage further
reflects the "do it quick with what is on hand" philosophy.

>Von Braun's team wanted to use 4 E-1s, but Rocketdyne
>countered with the suggestion of using 8 H-1s. The H-1 had been an inhouse
>project to redesign the S-3D/MA3/MB-3 series of engines based on operational
>experience. The major changes were moving the turbopump to below the gimbal
>block and to simplify the ignition sequence.

The H-1 was also more compact than the S-3 which offered some advantages in
construction of the engine supports, according to Ley.

--
Dave Michelson  --  [e-mail]  --  University of British Columbia

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

Date: Mon, 19 Jul 1993 18:27:15 GMT
From: Russ Renaud <[e-mail]>
Subject: SETI information
Newsgroups: sci.space

I'm rather new to this newsgroup, so I'm not sure if this topic has
been discussed.

Where on the Internet could one get some information
re: the SETI project?  I'm looking for some basic info,
as well as perhaps some technical details, such as what is
the smallest discernible signal that the SETI radio telescope
are capable of detecting?  How are they processing the
myriad of signals they must be receiving.

I saw in a past posting of SPACENEWS that some 160-odd signals have
been detected that warrant further investigation.  What form
do these signals take?

Any info would be appreciated.

[e-mail]

--

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

Date: 19 Jul 1993 18:59:03 GMT
From: Greg Moore <[e-mail]>
Subject: WATW Orbit (was Re: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

In article <229kmb$[e-mail]> [e-mail] (Pat) writes:
>In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
>
>Reasons for a High Inclination Orbit :
>
>1)  Cheap Soviet flights available.
>
>2)  Improved Earth Observation Missions.
>
>3)  Improved Logistics Flow missions.
>
    How is this different from 1?  And I could argue differently.
By keeping it at a 28.5 degree orbit, we maximize the amount of payload
on any one launch that we can deliever to the station.  We KNOW we will
always have some sort of lift capability.  We don't know what the
Russians will be doing in 5 years.

>4)  Improved space science/engineering base.  (  hihg inclination,
>is a far more rigorous environment then low inclination.
>
    Huh?  Please explain more.

>5)  Apparently ACRV return is simplified( This is what i was told,
>    I can't see an intuitive reason why this is).
>
    More land to land on.

>
>
>>
>>But Make vs Buy isn't a good paradigm if there is any sort of
>>technology development involved in the alternatives.  You have to
>>count into the balance what sort of 'profit' we get from doing it
>>ourselves and what kind of potential 'loss' there is if we don't do it
>>
>
>Make vs Buy is  properly cognizant of the benefits of
>Technology developement.   Nevertheless,  Every company does
>Make this  decision in it's business operations.
>
>IBM  Buys  Micro-processors.  DEC buys 4M DRAMS.
>
    No, actually IBM makes its own CPU's.  For example, the
486 they bought a license from Intel.  Now they've improved upon
it and sell it on their own motherboards (look for the forth-coming
Blue LIghtning 486DX3 chip).

    This may be what we want to do with the Soyuz capsule.  Buy
the design, optimize it for what we want, and build it in the US.
And still buy some from the Russians, if we need some.

>Certainly there are intangible benefits from  spooling up to
>do things,  but if that bleeds off developemnt  money from
>more vital activities,  that is equally a problem.
>
>Good Business people  make these analyses.
>
>
>>>COnsidering we put 1/3rd of our GNP  into relying on certain very unstable
>>>arab countries to sell us Oil,  I don't see what the problem is.
>>
>>You have an alternative?
>
>
>More energy Conservation,  Higher energy taxes,  developemnt of
>low energy consumption Infra-structure.   It's  bizarre, that it
>is  cash wise cheaper for me  to drive  to Chicago  then to
>take the train  ( The absolute lowest energy cost solution.
>
>Why is it, cheaper for me to drive to work in DC (Home to the best
>public transit system in AMerica)  then to take metro.
>
>
>pat
>
>--
>
>God put me on this Earth to accomplish certain things.  Right now,
>I am so far behind, I will never die.

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

Date: Mon, 19 Jul 1993 19:35:35 GMT
From: Henry Spencer <[e-mail]>
Subject: Why are meteor showers seasonal?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bruce Hoult) writes:
>> Around 0100 GMT on Aug 12 -- evening of the 11th in North America --
>> will be a good time to be in a dark area and watching the sky.
>
>Drat.  That's the middle of the afternoon.  What should it be like six
>hours later, or eight hours earlier?

It's anyone's guess.  That time is just the highest-probability peak time
based on the experience of the last couple of years.  But these things are
notoriously unpredictable, and surprises are not at all unlikely.  It's
even possible that nothing much will happen, although if the Perseids are
going to storm at all, it ought to be this year -- it's the best encounter
in centuries, and the last time it was even close to this good, they did
produce a storm.

The 0100 time isn't great for North American observers, either.  The sky
won't really be dark even on the East Coast.  But the timing is so hard to
predict that it's worth taking a look when you can.  Even the previous
and following nights are possibilities.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology
want results, greed works much better.  |  [e-mail]  utzoo!henry

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End of Space Digest Volume 16 : Issue 894
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