Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO517.TXT

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Date: Mon,  7 Dec 92 05:03:56
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #517
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Space Digest                Mon,  7 Dec 92       Volume 15 : Issue 517

Today's Topics:
                   absolutely, positively overnight
                             anniversary
                          cancelled Apollos
       Detonavion vs Deflagration (was Re: Shuttle replacement)
              Japanese Solar Mission_Yokoh:comparisons?
                        Lunar flight (3 msgs)
                           Orbit Question?
                     Pioneer and Voyager messages
                          Satellite orbits
                         Shuttle replacement
                       Spherical Space stations
             Voyager's "message"... What did it *say*?!?

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Date: Mon, 7 Dec 1992 03:24:47 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: absolutely, positively overnight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>In article <[e-mail]> [e-mail] writes:
>>>can't get a non-stop flight from John Wayne to Antarctica, so why would
>>>anyone expect to get a non-stop flight from John Wayne to orbit?
>>
>>Depends. Some earlier speculation on using DC-1 for sub-orbital hops which
>>would bring new meaning to the word "absolutely, positively overnight."
>
>Reportedly, if DC-1 can be built and suitably certified, Federal Express
>is most definitely interested.
>--
And if the airlines are interested, what about 30 minute transcontinental or
trans-oceanic flights.  :-)

Simon

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

Date: 7 Dec 92 08:36:09 GMT
From: Henry Spencer <[e-mail]>
Subject: anniversary
Newsgroups: sci.space

Lest we forget...  Twenty years ago today -- to be precise, at 0033 EST --
the last ship left for the Moon.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 7 Dec 92 08:02:26 GMT
From: Henry Spencer <[e-mail]>
Subject: cancelled Apollos
Newsgroups: sci.space.shuttle,sci.space

>> Do you mean that the Apollo 18 mission was targeted for Hadley, not 15? ...
>
>I don't remember the targeting assignments, but the crucial fact here is
>that there were two flavors of Apollo missions involved...

More Apollo archeology...

Site selection had settled down by early 1970, with minor ongoing
revision.  The cancellation of Apollo 20 had more or less coincided
with a decision that a landing in Tycho crater was too difficult, and
that had been the primary target for Apollo 20, so that one was easy
(although regrettable because Tycho was of great geological interest).
There was also some reshuffling of missions then, because the Marius
Hills mission required instrument development that might not be done in
time for its Apollo 16 slot, and also the site was reachable within the
mission rules only in summer.  So the list then was

    13    Fra Mauro
    14    Littrow
    15    Censorinus
    16    Copernicus
    17    Descartes
    18    Marius Hills
    19    Hadley

Apollo 13 was meant to visit Fra Mauro, because the Fra Mauro Formation
was thought to consist of material excavated by the impact that formed
Mare Imbrium -- a major event in lunar history, dating of which was
important, and also one that probably excavated material from deep down.
The Apollo site-selection board decided, in the wake of the Apollo 13
failure, that Fra Mauro was still first priority, so Apollo 14 went
there instead of Littrow.  They also recommended moving 15 to a site
near Davy crater, assuming Apollo 14 could get adequate photos.

Not only did the 14 photos not come through in time, but by then, it
was clear that more missions were going to die.  After lengthy discussion
and review of a number of sites, Littrow, Descartes, Hadley, and the
Marius Hills were deemed to be both feasible (both Copernicus and
Censorinus were now off the list due to excessively rough terrain)
and scientifically significant.

For Apollo 15, it was thought desirable to have a high probability of
major advances in lunar science, adequate photography without waiting
for Apollo 14 results, mission feasibility without deep analysis, and
a site suitable for either an H or J mission so that it could be flown
regardless of which type 15 was (at the time it was still an H, but
if missions were to be cancelled, cancelling the last H mission was
an obvious possibility).  This last was particularly significant
because it meant picking a site that didn't need the J's lunar rover
but would benefit if it were available.  Hadley got high marks for
providing access to several different geological features even without
a rover, being on various disciplines' high-priority lists, and putting
an ALSEP package at a high-latitude site (highly desirable to give
three-dimensional coverage for the seismometers and retroreflectors,
since most other sites were near the equator).

When two more Apollos, including the last H mission, were canned,
Hadley and Marius Hills fought it out for Apollo 15.  Hadley won by
a nose:  the two sites were very evenly matched until David Scott,
picked to command the mission, said he preferred landing at Hadley.
The board picked Hadley for 15, pencilled in Descartes for 16, and
left 17 open with several possibilities being debated.

Site selection for 16 ended up debating Descartes vs. Alphonsus.
Both looked like good places for highlands material and volcanic
material.  Descartes got the nod mostly because it was thought
preferable to have the 14 and 15 results fully in hand before
committing to a landing at Alphonsus; Alphonsus was left as a
candidate for 17.  In the end, it turned out that the Descartes site
was not volcanic at all, which caused a lot of re-evaluation of the
site-selection photogeology, because it had sure looked like it.
Confusion about the Moon's geological history was getting worse,
not better, with more Apollo results.

Site selection for 17 looked like it might produce a full-scale war,
so it got started early, well before 16 flew.  However, in the end
it wasn't that bad, because the fact that it was the last chance for
many years produced strong consensus on objectives:  pre-Imbrium
highlands as far from Mare Imbrium as possible, "young" volcanic
rocks, coverage from orbit of areas not previously seen up close,
and best coverage for some new geophysics instruments.  Three sites
made the short list:  Taurus-Littrow, Gassendi, and (a distant third)
Alphonsus.  T-L got top marks on most everything with the bonus of
a reasonable walking mission if the rover failed.  T-L had one
problem:  in worst-case conditions, Apollo's nominal-landing-area
ellipse would not fit the suitable terrain.  Gassendi also had
operational problems, though, since a slightly off-target landing
might make major objectives entirely unreachable.  The trajectory
people were encouraged to reconsider the T-L calculations based on
15's precision landing; the results cleared T-L and it was picked.

Most of the above is from NASA SP-4214, "Where No Man Has Gone Before",
which is the NASA History volume covering Apollo lunar exploration
proper (as opposed to hardware development).

>I don't remember exactly which CSMs got used for Skylab.

116 (the fifth J CSM) flew the first crew, 117 the second, and 118
the third.  111 (the last H) was Apollo-Soyuz.  119 (the last[?] J)
was allocated as Skylab rescue if necessary, then shifted to Apollo-
Soyuz backup.  Where 115 went I'm not sure.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Mon, 7 Dec 1992 08:10:53 GMT
From: Henry Spencer <[e-mail]>
Subject: Detonavion vs Deflagration (was Re: Shuttle replacement)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Simon E. Booth) writes:
>I don't know if this is  correct, but an article that came out in a local
>paper on 29 January 1986 that said that the Challenger ET exploded with a
>force of 1.7-2 megatons...

This would be difficult, since there isn't anything like that much fuel
on board.  (LH2/LOX is more powerful than TNT, but not by that much.)
I think somebody confused megatons with kilotons.  Worst-case explosions
for both Saturn V and shuttle are in the 1-2 kiloton range.

However, the Challenger ET did not explode.  At all.  It suffered major
structural failures and spilled its contents, which burned rather quickly.
No explosion.  The orbiter was destroyed by being thrown violently out of
control at Mach 3, which caused massive structural failure.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: 7 Dec 92 03:34:48 GMT
From: Ed Schmahl <[e-mail]>
Subject: Japanese Solar Mission_Yokoh:comparisons?
Newsgroups: sci.astro,sci.space,sci.physics

   The Yohkoh satellite is a very well implemented solar satellite
with a lot of improvements over Solar Max.  The SXT (soft X-ray
telescope) can map the X-ray Sun with 5 arcsec resolution in less
than a minute, and can zero-in to a smaller field for higher time
resolution of flare events.  It also has an X-ray spectrometer with
higher energy sensitivity One of its most powerful
instruments, however, is the HXT (Hard X-ray telescope), which can image
solar flares at energies up to 50 keV, with spatial resolution as good
as 8 arcsec.
    The satellite has been in orbit for a little over a year now,
and its results are revolutionizing our understanding of solar flares
and coronal mass-ejection events.


Ed Schmahl
Astronomy Dept.
University of Maryland

--
Edward J. Schmahl        |  Internet: [e-mail]  (128.8.251.56)
Lab for Astr & Solar Phys|  Gateway:  [e-mail]
Goddard Space Flt. Ctr.  |  SPAN:     CHAMP::SCHMAHL  (128.183.10.108)
Greenbelt, MD 20771      |  Voice:    [phone]

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

Date: Mon, 7 Dec 1992 06:03:31 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: lunar flight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:
>
>-From: [e-mail] (Henry Spencer)
>-Subject: Re: Lunar flight
>-Date: 6 Dec 92 01:49:57 GMT
>-Organization: U of Toronto Zoology
>
>-Except that Clinton & Co have already came out as opposed to any resumption
>-of manned space exploration, or any preliminary steps towards it, no matter
>-how cheap.
>
>Wrong.
>
I second that.  I truly hope our space program can survive the Clinton
administration.  Based on info I read during the campaign VP-elect Gore
is very pro technology.  While I didn't vote for Clinton/Gore, I won't
write off our space program yet.       Simon

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

Date: Mon, 7 Dec 1992 05:45:22 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: Lunar flight
Newsgroups: sci.space

On the subject of lunar flight, would a DC-type spacecraft be capable of
a lunar landing mission?  Theoretically, extra supplies could be carried
in place of cargo, but I'm not sure whether or not the normal crew
accomodations would be suitable for a flight lasting more than a few
days, plus time on the lunar surface.

I haven't seen any info on the DC-series outside of the net, so I do apologize
if my "theories" are inaccurate.  I'm not a scietist, just a space enthusiasti.
:-)
Simon

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

Date: Mon, 7 Dec 1992 08:14:10 GMT
From: Henry Spencer <[e-mail]>
Subject: Lunar flight
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Simon E. Booth) writes:
>On the subject of lunar flight, would a DC-type spacecraft be capable of
>a lunar landing mission?  Theoretically, extra supplies could be carried
>in place of cargo, but I'm not sure whether or not the normal crew
>accomodations would be suitable for a flight lasting more than a few
>days, plus time on the lunar surface.

Life support and such would probably need some souping up.  Propulsion
is up to the job, if refuelled in Earth orbit.  Landing and takeoff might
need some work, possibly including revised landing gear.  Earth reentry
would need careful design.

In short:  possible in principle, work needed on details.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Mon, 7 Dec 1992 06:13:58 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: Orbit Question?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>In article <[e-mail]> [e-mail] writes:
>>I have a question concerning geosyncrenous (please excuse my spelling, my
>>dictionary was  printed before space exploration got started) orbits. It is
>>my understanding that a body in geosyncronous orbit remains over the same
>>point on the earth and has the same rotational period as the Earth. My
>>question is what happens to a body that is in geosyncronous orbit at either
>>the north or south pole. Does it remain stationary above the pole?
>>If you can help me with this question please mail me.
>>Thanks.
>>
>>[e-mail]
>
>
>Geo sync orbits only exist at 0 latitude.  you could put a relay
>at 90 degrees, but youd need a huge amount of fuel to hover there.
>
>To do ppolar communications,  either LEO relays sats are used
>or you can create highly inclined highly elliptical orbits that
>leave the bird hovering for a few hours at perigee, a modest tracking
>antenna can then follow the bird.  if you have several in the constellation, you can have continous coverage.
>
This is what the Soviets did with many of their communications satelites to
hover their northern regions.  I read that the orbits were highly inclined,
300 by 25,000 miles or something like that.

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

Date: 7 Dec 92 04:48:29 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: Pioneer and Voyager messages
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>  For folks interested in trying to deciper the Pioneer plaques and the
>Voyager records, check your library or used book store for "Murmurs of
>Earth" by Carl Sagan et al.  Essentially it's a first-hand account of the
>designing of these messages, plus the bureaucratic hassles they went through
>to get them onto the spacecraft.   **Ad Astra Per Bureaucracia**
>
>  On a related note, Dave Barry once pointed out in a column (since reprinted
>in his book "Bad Habits") that the most likely lifeform to ever find these
>messages would be the interstellar equivalent of some back-country highway
>patrol officers.  He envisions one of them saying: "Looks like what we have
>here is a hydrogen-sniffin' perverted species who force their women to run
>around nekkid and probably say 'billions' a lot.  Whadda say we go wipe 'em
>out and then ooze over to the diner for some lunch?"
>
I read somewhere that if anyone finds the Pioneer and Voyager probes, they will
probably be interstellar travelers from earth at some point in the distant
future.  But would they still be able to understand the languages on the disks?

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

Date: 7 Dec 92 19:05:31 GMT
From: Jarno Linden <[e-mail]>
Subject: Satellite orbits
Newsgroups: sci.space

Ok, I know the format of the 2 line orbital element sets which are regularly
posted in sci.space.news.
What I now need are some formulae to translate these figures into a long/lat
coordinate or an (x,y,z) coordinate for a satellite at time t.
Preferbly something I can stick into some code.

Note: I am NOT asking for complete program listings, I don't want my E-Mail
costs to go through the roof (and as yet no FTP access).

|#|=AmigaShell==========================================================|#|#|
|1> echo >NIL: [e-mail]  _ //     This message has       | |
|1> echo >NIL: IFNA 3:772/90 Jarno Linden \X/ temporarily seized to exist |_|
|_________________________________________________________________________|/|

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

Date: Mon, 7 Dec 1992 05:25:29 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>> How many people does it take to operate the liquid hydrogen and liquid
>> oxygen plant? You've got to have one everywhere DC takes off.
>
>Well, no.  Liquid oxygen and hydrogen can be delivered by truck or
>rail car.  Haven't you ever driven behind a liquid hydrogen tanker
>truck on the interstate?  And LOX is delivered by tanker to hospitals,
>universities and industry all the time.
>
>You may want a holding tank, but that's much less complex than
>a separation plant.
>
How much of a problem would boil-off be during transportation and storage of
cryogenic fuels??

Simon

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

Date: 6 Dec 92 06:35:03 GMT
From: James Thomas Green <[e-mail]>
Subject: Spherical Space stations
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>
>
>Wouldn't spheres have the (dis)advantage of no tidally preferred direction?
>Meaning, depending on your preference, that it could rotate to any orientation
>preferred, or that station-keeping would be more difficult?
>

This could be fixed by using one or two teathered counterweights (which
could be useful payloads themselves).  One could be "upward" and the
other oriented "downward".  The gravity gradient would pull them tight
and give the craft a certain orientation relative to the Earth.

This concept was proven on one of the Gemini Flights when the G was
teatherer to an Agena it had met in orbit.  To a lesser extent
this was also shown on the recently failed (and hopefully soon to be
reflown) Shuttle teather experiment.


/~~~(-: James T. Green :-)~~~~(-: [e-mail] :-)~~~\
|                                                               |
|    Slogans of two generations:  1972:  Question Authority!    |
|                                 1992:  Why Ask Why?           |

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

Date: Mon, 7 Dec 1992 05:08:30 GMT
From: vincent seifert <[e-mail]>
Subject: Voyager's "message"... What did it *say*?!?
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Simon E. Booth) writes:
>>Pardon the odd question, but is there a recording of the "Voyager Record"
>>available?
>
>It's just recently come out on CD, although it's expensive ($80 or so).
>
>>I've always been interested in exactly what was recorded on it.
>
>In that case, you probably want the book "Murmurs of Earth" rather than
>the CD.

Warner New Media #14022, "Murmurs of Earth: the Voyager Interstellar Record",
contains the Sagan "Murmurs of Earth" book and a
two-CD set of the Voyager record; one CD has a data track on it containing
the images, displayable with a 286-or-better SVGA PC clone or a Mac II or
LC.  Both CDs have the how-to-play-this diagrams from the outside
of the Voyager record package on them, which is cute.  :)

List price is $79.95, but I got mine for $49.99 at Egghead.  The CDs themselves
have another number on them, WNM 14021, so you may be able to get them
separately.

I like mine.  If you watched "Cosmos", some of the music may be familiar.

Vince Seifert   Equipment Tech III   [e-mail]
CSUS hired me to fix their computers, not to air their policies.
--
Vince Seifert   Equipment Tech III   [e-mail]
CSUS hired me to fix their computers, not to air their policies.

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

End of Space Digest Volume 15 : Issue 517
------------------------------