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Subject: SPACE Digest V10 #259

SPACE Digest                                     Volume 10 : Issue 259

Today's Topics:
         NASA Headline News for 11/17/89 (Forwarded)
               Re: Voyager's last photo
         Some corrections on LV family trees
           Hollow cathodes as electron collectors.
            Re: Electronic Journal article
             Looking for F. Flores-Amaya
               Re: Population pressure
               Re: Mars space elevator
----------------------------------------------------------------------

Date: 17 Nov 89 20:58:35 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 11/17/89 (Forwarded)

[Cross-posted to sci.astro because of an item of interest. -PEY]

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Friday, Nov. 17, 1989                        Audio:  202/755-1788
-----------------------------------------------------------------

This is NASA Headline News for Friday, November 17th......

NASA Administrator Truly and other agency officials are briefing
Vice President Quayle and members of the National Space Council
this morning on NASA's recent study of requirements for a new
moon/Mars initiative.

Meanwhile, the Washington Post reports that Vice President Quayle
wants the space council to study a proposal which calls for
putting in orbit a "stand-alone" space station consisting of
seven modules to be inflated in orbit with walls reinforced by
kevlar.  The "inflatables" concept has been proposed by a team of
scientists from the Lawrence Livermore Laboratory.  The
scientists claim their concept will speed up, and reduce the
costs of putting humans on Mars.

At Kennedy Space Center, shuttle managers yesterday decided to
replace one of the electronics assemblies on the space shuttle
Discovery, after it failed to pass inspections.  The right IEA
will be replaced with a unit from the STS-32 booster stack.
Officials said the work is not expected to delay the launch,
which is now targeted for no earlier than Wednesday, November
22nd.

At Vandenberg Air Force Base, the launch of the Cosmic Background
Explorer satellite...aboard a Delta launch vehicle...remains on
schedule for tomorrow morning.  A 30-minute launch window opens
at 9:24 A.M., Eastern time.  The weather for launch day appears
favorable at this time, with scattered clouds at 20,000 feet and
visibility of 7-miles or greater.  NASA Select television will
provide live coverage of the launch.

And...a team of astronomers say they have discovered the biggest
structure ever found in the universe--a "great wall" of galaxies
that is at least 500 million light years long, and 200 million
light years wide.  One light year is equal to about 6-trillion
miles.  The astronomers say the "Great Wall," which can not be
seen with the naked eye, is about 300 million light years from
Earth...and may be found to be double its currently known size.
Before discovery of the new massive sheet of galaxies, the
largest light-emitting structures in the universe were thought to
be galaxy superclusters, some of which measure about 50 million
light years across.


                         *********





-----------------------------------------------------------------
Here's the broadcast schedule for public affairs events on NASA
Select television.  All times are Eastern.

Saturday, Nov. 18.....

     8:30 A.M.        Coverage of the launch of the Cosmic
                      Background Explorer satellite from
                      Vandenberg Air Force Base.  The 30-
                      minute launch period begins at 9:24 A.M.

Monday, Nov. 20.......

     1:00 P.M.        The NASA radio programs will be
                      transmitted.  (audio only)

Wednesday, Nov. 22....

     5:30 P.M.        Coverage of the STS-33 launch from
                      Kennedy Space Center.  The four-hour
                      launch period begins at 6:30 P.M.

All events and times are subject to change without notice.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch (LPC), NASA
Headquarters, Washington, D.C.

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

Date: 9 Nov 89 20:06:24 GMT
From: hpfcso!hpfcdj![e-mail]  (Bob Myers)
Subject: Re: Voyager's last photo

>Could you explain why asteroid belts don't need to be dodged.
>I've often wondered.

The relatively low density of the asteroids in question.  Yes, there are a
lot of rocks out there, but there's a WHOLE lot of space around 'em! :-)


Bob Myers            | "Writing is not necessarily something to be ashamed of -
myers%hpfcla@hplabs. |  but do it in private, and wash your hands afterwards."
hp.com               |                   - Lazarus Long/Robert A. Heinlein

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

Date: 17 Nov 89 17:11:18 GMT
From: shlump.nac.dec.com![e-mail]  (Gary Hughes - VMS Development)
Subject: Some corrections on LV family trees

The book by Baker referred to in a previous reply is a good place to start. The
book by Gatland is not bad either. If you want details of early LVs, you might
try looking for 'Spacecraft and Boosters' also by Gatland. This was intended
to be an annual publication, but the first edition (1962 I think) detailed all
of the LVs used that year. The second, and last, edition added only the LVs
that were new for that year.

Some corrections...

Jupiter C (aka Jupiter Composite Reentry Test Vehicle) was based on a modified,
stretched Redstone buring Hydyne/LOX. Two solid propellant upper stages were
added for Jupiter C. Explorer I was launched by a Juno I which was a Jupiter C
with a fourth solid propellant stage. The Redstones used for Mercury were also
the enhanced version, with no upper stages (unless you count the Mercury
posigrades...)

Wresat was launched on a Sparta which was an unmodified Redstone stage with two
solid propellant upper stages replacing the warhead. This variant still had the
Redstone guidance section, and was intended for reentry tests flown from
Woomera, South Australia (Project Dazzle). There was a spare Sparta left over
and it was cheaper to give it to the Australians and leave the ground equipment
than it was to ship it back. The Redstone shed is still there, btw, or at least
it was when I visiteda few years ago.

Juno II was a Jupiter IRBM with the same upper stage assembly as Juno I. Juno
III was to have been similar but using larger solid propellant motors. It was
cancelled as it did not offer sufficient improvement in performance over Juno
II. Juno IV was to have been the Jupter with a single, fairly large upper
stage. It was discovered very early that this would lead to structural problems
in the Jupiter and was also cancelled. Juno V was the original name of the
Saturn I first stage (S-I).

The first Thor based LV was the Thor Able. The Able upper stages were the upper
stages from Vanguard, essentially an Aerobee topped by an ABL X-248. Several
minor variants were flown to test Atlas reentry vehicles and later some lunar
probes. Able Star followed and was the first space-restartable upper stage.
Agena A came out of the original recsat program (White Cloud?) and had been
under development prior to Explorer I. Several variants of Agena (B, D)
followed, adding increased capability and restart. Prior to shuttle, over 50%
of US satellites were built on or launched by Agena (the darling of the
military space program). The Agena motor was originally developed for the B-58
Hustler bomber (for a brief time, Thor Agena was called Thor Hustler).

Thor Able with different guidance became Thor Delta, the first NASA-managed LV.
It was eventually simply called Delta. In 180-some launches there have been
over 50 different Delta variants.

Thor has also been flown with various solid upper stages including Altair and
the various Burner variants.

Atlas has also flown with various upper stages. There were four Atlas Able
flights very early on. Others include Agena, the Burners, and the SGS series
(SGS-II is a two stage affair using Star 48s in both stages, sort of a two
stage PAM-D with attitude control). A special variant, now known as Atlas G,
was developed for use with Centaur. Apart from being longer and lacking the
tapered forward section, it relied entirely on the Centaur stage for guidance
and control. The current Atlas-I is an Atlas-G/Centaur D-1A with a larger
payload fairing. The Atlas-II family add various upgrades.

The Titan II used for Gemini was unmodified. In fact GT-2 was a production
model ICBM rather than one built specifically for NASA. The USAF had grand
schemes for its own followon Gemini program (Blue Gemini) and planned to keep
the Titan production line open. The various Titan 3 and later models have
employed upgraded stages though.

Enough rambling for now. If you have specific questions or want details on the
old 'Spacecraft and Boosters' book, reply or send mail and I'll dig out what I
can.

gary

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Date: 17 Nov 89 19:15:52 GMT
From: nems!dtoa1![e-mail]  (McAllister)
Subject: Hollow cathodes as electron collectors.

I am a student writing a paper on hollow cathodes as plasma contactors.
I understand how they work as electron emitting cathodes, but I am not
quite sure how they work as electron collectin (ion emitting) anodes..

Is a passive collector required in addition to the hollow cathode with
the cathode just providing a means of extending the projected area to
the plasma.

Since I am not an expert in the field I would appreciate any simple
explanations of this phenomenon.

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

Date: Fri, 17 Nov 89 19:43:30 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Electronic Journal article


>                         THE ELECTRONIC JOURNAL OF
>                 THE ASTRONOMICAL SOCIETY OF THE ATLANTIC
>                    Volume 1, Number 4 - November 1989
>...
>                      DOES EXTRATERRESTRIAL LIFE EXIST?
>                              by Angie Feazel
>...
>    ...  Doctors Francis Crick and Leslie
>    Orgel are firm believers in the theory that extraterrestrials, either
>    deliberately or inadvertently, "planted" some form of microorganism
>    and "we evolved from that" (35).  Though we have no way of proving this
>    theory wrong, we think that the harsh conditions in outer space would
>    kill any organism sent to populate Earth.  As Robert Rood and James
>    Trefil point out, if a spore were to be ejected from a planet, the
>    gravity of the nearest and largest celestial object would attract
>    it.  In our solar system, that would be the Sun (108).  The spore
>    would have to navigate the depths of interstellar space and find a
>    suitable planet on which to evolve.  The chances of this happening by
>    pure coincidence is virtually zero.

There wouldn't be much risk of the spores falling into the system's star.
As several people have pointed out, anything sufficiently small, starting
out at earth orbit, will eventually be driven out into interstellar space
by light pressure. (As size decreases, the surface to volume ratio increases.)
The main problem with the model is to find some way for the spores to get
*into* another star system. One possible mechanism is for them to be captured
by a comet out where the light pressure is low, then carried into the inner
part of the star system. From this point, they could be ejected by the
evaporating comet and possibly be captured by a planet, or the entire
comet could crash into a planet. Recent computer simulations have indicated
that it is theoretically possible for a comet to "soft-land" into an ocean,
with part of the material not getting hot enough to destroy organic life.

Also note that it is not necessarily a requirement that the spores arrive
in a fully viable form. Since the "developed on Earth" models call for
a period of time in which complex molecules floated around free, these
molecules could just as well have come from somewhere else. Life-created
compounds are often far more durable than life itself. I believe original
proteins and possibly even DNA sequences have been found in dinosaur bones.
                                 John Roberts
                                 [e-mail]

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

Date: 10 Nov 89 16:37:17 GMT
From: hpfcso!hpfcmgw![e-mail]  (Dave Koons)
Subject: Looking for F. Flores-Amaya


Looking for Felipe Flores-Amaya. Please return email.

------------------------------------------------------
"One of these days..."               Dave Koons

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

Date: 17 Nov 89 22:25:04 GMT
From: milton!maven![e-mail]  (Games Wizard)
Subject: Re: Population pressure

In article <[e-mail]>, [e-mail] (Steve Rehrauer) writes:
>  >Realistically, I think that governments would not solve the
>  >population problem by going into space as there are other ways of
>  >population control that are (at this time) cheaper, easier and more
>  >acceptable by most people.
>
> Realistically, short of genocide or sharply repressive actions, I don't
> think there's much any government can do to directly curb population
> growth.  The best "cure" for high population growth seems to be an
> affluent and well-educated general population, which is hardly cheap
> or easy to attain.  And if non-military, off-world habitats ever become
> a reality, I'd expect them to be accessible only to the most affluent,
> and not the "excess" population.  At least in the early years, at any
> rate; and even afterwards I'd expect there to be a vested interest in
> maintaining the status quo.  (I didn't say I desire that scenario, but
> it seems most likely, IMO.)


Seems to me that we have forgotten the Austrailia syndrome.
(Also used in"The Moon is a Harsh Mistress" Heinlein.  But there is
a new twist...  Instead of criminals per se, we could send everyone
who has AIDS ( or has been exposed ) to the moon, and let them struggle
it out up there, then when they have all died, we can go and see how
much work they have done for us...

I wonder how many political leaders would be in favor of this if it were
a real world option today?  We can bet that the Christics would be opposed :
Just think what would happen if thier transport blew up, and spread that AIDS
infected body parts vapor all over the country.

The other problem is that Penal colonies seem to have a historical
habit of doing better than intended.

Well, just pointing out that "rich and affluent" is not the only scenario
in town...

-------------------------------------------------------------------------------
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            (206) 935 - 4384
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My boss dosn't know what I do.

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Date: 17 Nov 89 14:42:24 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: Mars space elevator

In article <[e-mail]> [e-mail] (Steve Masticola) writes:

>] Um... wouldn't it be a lot simpler to move Phobos?
>
>The only place where Phobos wouldn't still be a problem is in
>synchronous orbit, or above. ...

>Of course, if you've got a technology that can move small moons around
>when they're inconvenient, who needs space elevators?

There is another place Phobos is not a problem: crashed onto the surface
of Mars.   We could brake Phobos by playing out a tether towards
Mars.  The tether would have a *large* sail, which would be dragged
through the martian atmosphere at supersonic speed.  Phobos would
gradually spiral down towards the planet.

Another possibility is to, over time, transport Phobos's material down
a tether, and release it into Mars-intersecting trajectories.  This
boosts the remainder of the moon away from the planet.  The other way
would also work -- release material from an outward-directed tether so
that it escapes into solar orbit.  The remainder of the moon spirals
down towards Mars.

I'd worry most about dust and debris from Phobos hitting the elevator.

    Paul F. Dietz
    [e-mail]

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End of SPACE Digest V10 #259
*******************