Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_6/V16NO655.TXT

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Date: Wed,  2 Jun 93 05:04:11
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #655
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed,  2 Jun 93       Volume 16 : Issue 655

Today's Topics:
                Adaptive Optics (was Space Marketing)
     Can we use HST to look at possible Jupiter/comet collision?
    Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994
             Hey Sherz! (For real!) Cost of LEO (3 msgs)
                Liberal President murders spaceflight?
                      Magellan Update - 05/29/93
                      Magellan Update - 05/30/93
                      Magellan Update - 05/31/93
                              Moon Base
                   Moon vs. asteroids, Mars, comets
                            Sagan / TAPPS
                 Space Marketing would be wonderfull.
         Von Braun and Hg (was Re: About the mercury program)
    Voyager Discovers the First Direct Evidence of the Heliopause

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
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----------------------------------------------------------------------

Date: Tue, 1 Jun 1993 16:51:52 GMT
From: Frank Crary <[e-mail]>
Subject: Adaptive Optics (was Space Marketing)
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Dani Eder) writes:
>Last year I was involved with a NASA study on laser power beaming
>to orbiting spacecraft (I was working the spacecraft end).  As
>a result, I got to sit in on presentations on the current state
>of the art in wavefront control.  The coherence scale of the
>atmosphere is on the order of 6 cm on the ground.

>The whole mirror has to be driven at about 200Hz, since that is
>the characteristic time for the atmospheric distortions (it is
>a funtion of wind velocity in the atmosphere, and the turbulence
>it generates.

Which frequency was this at? If memory serves, both the time scale
and the coherence length are roughly proportional to wavelength
(actually, wavelength to the 1.2 sticks in my head, but I'm not
sure which it applies to...)

                                                  Frank Crary
                                                  CU Boulder

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

Date: 1 Jun 1993 12:52:33 -0400
From: Pat <[e-mail]>
Subject: Can we use HST to look at possible Jupiter/comet collision?
Newsgroups: sci.space

Gee, I don
't know about HST, but I think EUVE  runs a real time video
feed.  It won't be as precise as HST,  but it should give
something..

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

Date: Wed, 26 May 1993 17:24:15 GMT
From: Stupendous Man <[e-mail]>
Subject: Comet Shoemaker-Levy, Possible Collision With Jupiter in 1994
Newsgroups: sci.space

   Phil says, speaking of using HST to observe a collision between
Jupiter and Comet S-L,

>The photometer would be the most useful instrument in this case, I
>think...

   Gosh, Phil, I don't MEAN to rain on your parade, but the High-Speed
Photometer will be removed from HST and replaced by COSTAR (the
device with special mirrors to fix the spherical aberration for the
other instuments) in the repair mission in late 1993 or early 1994.
Sorry.

--
-----                                                    Michael Richmond
"This is the heart that broke my finger."    [e-mail]

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

Date: 1 Jun 1993 10:25:46 -0700
From: Ken Hayashida <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

[e-mail] writes:

>It is real funny for me to read the "experts" talking about the cost of
>satellite construction from those who have never laid their hands on one, or
>been responsible for the construction and operation of one.

>If you want to make statements like this back them up with numbers both the
>cost of reconstruction and the cost in lost revenues during the construction
>period.

>Dennis, University of Alabama in Huntsville

Amen...

Let us use acceptable scientific and technical writing skills when posting
these claims.  If you cannot cite an exact technical document (with
specific document numbers and page numbers), if you cannot give a
reference which is available to the general public, and if you can't
discuss the methods used to derive those numbers; then your numbers and
cost projections are meaningless.

In the near future, I hope to elaborate on this by posting detailed
responses to misinformation which was recently posted by several shuttle
critics regarding the engineering and record of the shuttle program.
Rest assured friends, that my data will all be cross referenced so you
can obtain the numbers on your own.  Rest assured folks, that my calculations
and methods will be laid out in full...so you can judge the method itself.

Let us all adopt this practice when making assertions about costs involved
with spaceflight.

[e-mail]

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

Date: Tue, 1 Jun 1993 17:58:13 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

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

>>>Don't include contingency satellitte return missions.  It would have
>>>been cheaper to build new ones  and pop them off.

>If you want to make statements like this back them up with numbers both the
>cost of reconstruction

Already done Dennis. A very conservative estimate would be that a typical
replacement to a typical satellite could be built and luanched for about
$225 M which is less than half the cost of a rescue mission.

Perhaps YOU would like to show us a case where it was cost effective?
In spite of your complaints, we haven't seen one.

>and the cost in lost revenues during the construction period.

Intelsat is the only place I know of where this applies. Yet it was
only performed after receiving huge taxpayer paid subsidies to do it.
They didn't think it was worth paying the total cost themselves.

   Allen
--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------15 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: Tue, 1 Jun 1993 18:01:56 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

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

>It is real funny for me to read the "experts" talking about the cost of...

Are you perhaps suggesting that YOU are an expert?

Note I'm not saying I am an expert on satellite design either. But I am
a good engineer with a lot of experience. From that I know when the numbers
don't add up and when the wool is being pulled over my eyes.

  Allen

--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------15 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: Thu, 27 May 1993 18:46:37 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Liberal President murders spaceflight?
Newsgroups: sci.space

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

>>
>>>Let's not forget,  Carter was a nuclear engineer,
>>>and seemed a whole lot more realistic  about what could be done
>>>as opposed to reagan  who had no idea  what the laws of physics were.
>>
>>>pat
>>
>>Funny. Maybe we ought to shoot all the nuclear engineers and
>>find more people ignorant of physics. Then we might get some
>>research into advanced propulsion done.
>>

>My response:

>Carter's "Nuclear Engineering" training consisted of the Navy's six
>month school: he had NO formal degree.

Uh, excuse me, Dennis, but do you know *anything* about the Navy's
nuclear power program?  First of all, Carter most certainly did have a
degree, and I would expect that it was in some engineering discipline,
science, or math.  The Navy doesn't make officers without one.
Second, just how many hours of 'nuclear engineering' do you think your
idea of a 'real' nuclear engineer should take?  Is it more than 1000
hours of in-class time?  That's what Carter had (40 hours/week for 6
months = 1040 hours).  A typical engineering degree is only about 2450
hours (spread over 4-5 years), and that's for *everything* --
including all the Math, English, Sociology, and all that
'non-engineering' stuff.  Carter had that *plus* another 40% just on
nuclear power.

>Carter calling himself a
>Nuclear Engineer is a travestry.

Really?  Then I guess most of the nuclear engineers in the country
must be, too.

>All Carter managed to do was let the
>US lose its stranglehold over enriched uranium, cancel the breeder
>(which never made it back) therby giving France the leadership role,
>and stiffle fusion research. We also got the uneconomical once through
>fule cycle from Carter.  It turns out that he is a better carpenter
>than engineer (or businessman).

I'd suggest you look up a report done in 1977 (by Ford (the company)
under the management of Mitre).  It's several hundred pages studying
the technical, safety, and economic aspects of nuclear power,
breeders, etc.  Your preceding paragraph is full of misconceptions
about the economic viability of breeder reactors at current market
prices for uranium, along with misconceptions about a lot of other
things.  Oh, and in case you didn't know it, both Britain and France
already had enrichment facilities long before Carter came into office.

If you'd like, I can look up the exact title of the report when I get
home.  It'd be nice if you had some facts when you make such sweeping
and positive statements.

--
"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: 1 Jun 1993 17:21 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 05/29/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                      MAGELLAN STATUS REPORT
                           May 29, 1993
                           3:00 PM PDT

1.  The Magellan Transition Experiment continues to successfully
maneuver the spacecraft toward the desired aerobraking corridor.  The
spacecraft has now made 31 atmospheric drag passes with the periapsis
below 150 km and all subsystems are reported to be nominal.

2.  Corridor Orbit Trim Maneuver (COTM) #3 was performed at 10:57 AM
PDT this morning and lowered the periapsis to 141.1 km.  The dynamic
pressure at this altitude is 0.23 N/M2.  The nominal range for the
desired aerobraking corridor is from 0.25 to 0.32 N/M2.

3.  The performance of the spacecraft during the atmospheric drag
passes as well as analysis of orbital changes now indicate an
atmosphere which is 17.5% above the "Single CO2" model.

4.  Currently the solar panels increase by 35 degrees C during the
drag pass, reaching a peak of 50 degrees C.  The aerobraking limit is
about 160 degrees.  The estimated temperature of the HGA is 85 degrees C.
(with a limit of about 180 deg.)

5.  The periapsis altitude will continue to drift downward over the
next week or more, and the first "1/2 up" COTM is expected about June
5-7th.  If the drift is slower that expected, a small (1/2n) "down"
COTM may be considered for early next week.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

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

Date: 1 Jun 1993 17:23 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 05/30/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                      MAGELLAN STATUS REPORT
                           May 30, 1993
                           2:30 PM PDT

1.  The Transition Experiment continues to successfully maneuver the
Magellan spacecraft toward the desired aerobraking corridor.  The
spacecraft has now made 39 atmospheric drag passes and the periapsis
is now at 141 km.   All subsystems are reported to be nominal.

2.  The main purpose of this aerobraking experiment is to lower the
apoapsis of Magellan's orbit under 700 km.  At the start of
aerobraking, apoapsis was at 8460 km.  As of today (May 30) it is at
8200 km and will cross the 8000 km distance on June 2nd.  The current
prediction is that we will achieve the 700 km apoapsis about August
4th, leaving a nine-day margin in the Transition Experiment.

3.  The performance of the spacecraft during the atmospheric drag
passes as well as analysis of orbital changes now indicate an
atmosphere which is 17.5 to 20% above the "Single CO2" VIRA (Venus
International Reference Atmosphere) model.

4.  The solar panels continue to increase by 35 degrees C during the
drag pass, reaching a peak of 58 to 60 degrees C.  The aerobraking limit
is about 160 degrees.  The estimated temperature of the HGA is 94 degrees
C. (with a limit of about 180 degrees)

5.  The periapsis altitude will continue to drift downward over the
next week or more, and the first "1/2 up" COTM (Corridor Orbit Trim Maneuver)
is expected about June 5-7th.  This will be followed by a series of 1/2 up
COTMs at intervals of 4 to 9 days as the general drift continues downward.

COTM = Corridor Orbit Trim Maneuver
VIRA = Venus International Reference Atmosphere

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

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

Date: 1 Jun 1993 18:27 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 05/31/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                        MAGELLAN STATUS REPORT
                             May 31, 1993

1.  The Transition Experiment continues successfully as the Magellan
spacecraft has completed its "walk-in" phase to the desired
aerobraking corridor.  The spacecraft has now made 46 atmospheric drag
passes and the periapsis is now under 141 km.  All subsystems are
reported to be nominal.

2.  The performance of the spacecraft during the atmospheric drag
passes as well as navigation data now indicate an atmosphere which is
17 to 30% above the "Single CO2" VIRA model.

3.  The solar panels continue to increase by 35-40 degrees C during
the drag pass, reaching a peak of 62 degrees C.  The aerobraking limit is
about 160 degrees.  The panel experience higher temperatures during
other portions of the orbit while facing the sun.

4.  The periapsis altitude will continue to drift downward at about
0.2 km per day over the next week or more, and the first "1/2 up" COTM
is now planned for early June 4th.  This will be followed by a series
of 1/2 up COTMs at intervals of 4 to 9 days as the general drift
continues downward.

COTM = Corridor Orbit Trim Maneuver
VIRA = Venus International Reference Atmosphere
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

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

Date: Tue, 1 Jun 1993 17:27:33 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Moon Base
Newsgroups: sci.space

[e-mail] (Nick Janow) writes:

>[e-mail] (Gary Coffman) writes:

>> I do think that asteroid and comet processing can be developed for similar
>> expenditures as a lunar base. I also agree that it'd take at least a
>> decade, probably longer, to do that development.

>We have different opinions on that.  Several other people in this group share
>my opinions, and I haven't seen anyone supporting yours.  Have you any
>references for studies that show asteroid mining to be priced low enough to
>be worth considering?

Okay, I'll at least say that I support Gary's position. Especially based
on the stuff I saw at the ET resources conference last March...

I don't really have time to get into technical details right now, it's
hard enough keeping up with my schedule as the net's incarnation of evil.

I just realized, as long as we're taking a vote...

>snip!<

>The probes are cheap; the price of actual processing of the materials is
>completely unknown.  What sort of near-Earth objects could feasibly be moved
>to LEO with existing technology?  If a nice nickel-iron or volatile-rich
>chunk could be moved to LEO for the same cost as delivering an Al-O
>processing system to Luna, then the asteroid mining route looks reasonable.

They're not talking about moving the whole thing back, but just what
is needed...
....
>investment.  The asteroid project could provide more benefits for later
>private projects in the long term, but that must be balanced with initial
>cost and risk.  Considering all the non-economic factors, the moon could be a
>better choice at this point in time. It might not be, but it shouldn't be
>immediately ruled out by one factor that favours asteroidal mining.

Yah, but you're saying the Moon may be better if more people mistakedly
believe it's better. When the work of Tony Zuppero and everyone else like
him reaches critical mass, this may change.

>What's the dollar return on investment for the SSC?  That's a matter of
>national prestige, investment in knowledge, and porkbarrelling.  Was Desert
>Storm purely for economic and security reasons, or did prestige and internal
>political factors play a significant role?  Was Apollo a result of security
>(Cold War) reasons, or for prestige and internal politics?  An American
>president could sell a lunar base project idea to the public if he thought it
>would divert attention from other issues, keep the military contractor
>economy going, etc.

_NONE_ of that has any bearing on whether or not the Moon or Asteroid/Comet
is a _good idea_. _And_ a lot of the stuff you're talking about for the
lunar base is equally relevant to the comet mining stuff, since a _lot_
of the research seems to be coming out of the Department of Energy.

>> "We lose money on each sale, but we make it up in volume." Sorry, I don't
>> buy that.

I think Gary said that; I hope I have the attribution right.

I just had to include it because it's a favorite example of mine.

>Oh, sorry.  I thought we were discussing government-funded projects, which
>aren't required to show a positive balance each quarter.  :)

No, but when they finally hit bankruptcy the payback's tough.

>It's also nice to know that asteroid mining will definitely show black ink
>right from the start.

No, but it may be better prepared to survive in case of political/economic
problems than the lunar approach. Or it may not. I think the jury's still
out.

>> Getting rid of that dive into, and climb out of, a gravity well is a big
>> cost win. The delta-v has to be delivered quickly, and that means high
>> power engines and lots of reaction mass. In space transport, the delta-v
>> can be built up slowly using much cheaper low power/low reaction mass
>> propulsion. Staying away from gravity wells is a big cost win.

Gary, a lot of the proposal's I've seen involve gravity wells, and moving
the stuff to leo...

>I agree completely.  I'm just not convinced that the technology to deliver
>pure H2, O2, metals, and silicates to LEO from asteroids would be cheaper or
>politically feasible at this time.

Many people share those doubts about lunar materials. I think the people
who were labelling me as an infantile space case a week back had doubts about
EVERYTHING.

>> But few will bother to stop at Luna, climbing in and out of that well is
>> too expensive for a visit to a slag heap of light metals and silicates.

>It won't be too expensive if the light metals, silicates and volatiles (O2,
>S) are easier/cheaper to extract and process, and energy and reaction mass is
>cheap (as well as transport via efficient mass driver).

Maybe. But a lot of this stuff requires large amounts of volatiles in the
form of H2/CH4 etc...

Apparently the other Nick is right about the need for that stuff in a lot
of the lunar industrial processes.

>--

>[e-mail]
--

+-----------------------+---------------------------------------+
|Phil Fraering          | "...drag them, kicking and screaming, |
|[e-mail] | into the Century of the Fruitbat."    |
+-----------------------+-Terry Pratchett, _Reaper Man_---------+

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

Date: Tue, 1 Jun 1993 19:00:42 GMT
From: [e-mail]
Subject: Moon vs. asteroids, Mars, comets
Newsgroups: sci.space

Richard A. Schumacher ([e-mail]) wrote:
: Perhaps an illustration would help: if there were an
: asteroid of solid platinum in LEO right now, it would
: not pay (by a factor of 2 or so) to bring any of it back
: using the shuttle.
: (Assumptions: max shuttle landing payload weight = 20,000 lbs.
: Pt at $700 per oz. Shuttle flight costs >= US$350,000,000.)

Of course, that same argument applies to launching a bird to Clarke
orbit, too.  You can't use a Shuttle because it's too expensive to get
the whole Shuttle up to GEO.

But that's just plain silly.  If there actually were a chunk of solid
Pt in LEO, it would make more sense to launch a teleoperated device
which would rendezvous with it, attach to it, then de-orbit the whole
thing to a nice, safe site where terrestrial crews could dig it up
(from the big hole it would make upon landing) and process it in the
"usual" way.  No Shuttle involvement at all, except maybe in having a
crew there to put the de-orbit rocket on your Pt chunk.  (We don't have
any experience in using a teleoperated device to grapple a rock in
space; we might need a crew there to fix things.)

The Shuttle is not built for on-orbit material processing on the scale
of a 1000-tonne rock.  NASA would not allow a rock of unknown material
and structural properties to be put into the payload bay for the trip
downhill.  But this isn't the reason we built the Shuttle in the first
place.  The Shuttle provides limited access to space for people and
materials, and it has taught us a lot about how to build the next
generation of reusable spacecraft.  (And it's taught us more about how
how NOT to build the next generation, but we seem to have trouble
learning from mistakes made on previous Programs.)

Richard's example is useful because it gives you a feel for the scale
of economics involved, but it misses a major point: it is probably not
economically viable to use a general-purpose R&D spacecraft for a
special-purpose commercial endeavor.  This should surprise nobody.
Until space technology develops further, special-purpose spacecraft
are required for special-purpose applications.

-- Ken Jenks, NASA/JSC/DE44, Mission Operations, Space Station Systems
      [e-mail]  [phone]

     "The Operations Support Officer develops and implements an
      operational support structure that maximizes the availability of
      on-orbit hardware within allocated resources to sustain the
      operational capability of the Space Station Freedom (SSF)
      throughout its lifetime.  The OSO also supports monitoring and
      commanding of the mechanical systems, planning and integrating to
      resolve mechanical, structural and assembly issues, and operation
      and troubleshooting of mechanical software applications."
    -- Space Station Freedom Operational Support Officer
       Responsibilities and Functional Overview

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

Date: Tue, 1 Jun 1993 17:12:52 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Sagan / TAPPS
Newsgroups: sci.space

In <[e-mail]> [e-mail] ("F.Baube[tm]") writes:

>From: fred j mccall 575-3539 <[e-mail]>
>>
>> [e-mail] ("F.Baube[tm]") writes:
>> >
>> >Well, don't forget that there were psychopathic
>> >statements from the Pentagon brass like
>> >"In the event of nuclear war, just lay a door over
>> >a hole in the ground and shovel some dirt over it."
>> >I believe this was said in testimony to Congress.
>>
>> Well, this makes more sense than going outside to watch!  Actually,
>> dirt is a fiarly good shielding material, so if you don't happen to
>> have a bomb shelter handy, this is probably the best advice you're
>> going to get.

>Agreed !  But ..

>I for one got the distinct impression at the time that
>Dr Strangelove was alive and living at FEMA, plotting
>post-holocaust fun with Ollie.

>Give Sagan a little credit for injecting into the discus-
>sion a bit of rational thought about the ultimate effects
>of such a war.  Something more complex and long-term than
>planning how to collect taxes and corral dissidents.

If I thought that Carl Sagan had used any 'rational thought', I would
give him credit for it.  However, what he did was pervert science to
support his political agenda.  'Credit' isn't the word I would use for
what is earned by that.

--
"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: Tue, 1 Jun 1993 16:43:03 GMT
From: Frank Crary <[e-mail]>
Subject: Space Marketing would be wonderfull.
Newsgroups: sci.environment,misc.consumers,sci.astro,talk.environment,talk.politics.space,sci.space

In article <[e-mail]> [e-mail] (bill nelson) writes:
>: logically cool one at that.  Initially, I think space advertising will
>: appeal to a lot of people simply due to its novelty.  Maybe it will
>: proliferate, but I think it will go the way of Burma-Shave signs and
>: highway billboards.  Who really reads billboards anyways?

>Unfortunately, the only place highway billboards have gone away is where
>they have been legislated out of existance...

Then the only place they have gone away is in Utah: Allowing highway
billboards is a condition for receving federal highway funds. Utah
refused to allow tabaccoo ads on non-interstate highways, and doesn't
get non-interstate highway funds as a result...

                                                       Frank Crary
                                                       CU Boulder

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

Date: Tue, 1 Jun 1993 17:27:26 GMT
From: "joseph.l.nastasi" <[e-mail]>
Subject: Von Braun and Hg (was Re: About the mercury program)
Newsgroups: sci.space

I stated:

> >Van Braun had very little to do with Mercury.  For a very good review

Dennis commented:

> Dr. Von Braun did not have too much to do with the capsule except to make
> sure that the interface between the capsule and the Mercury Redstone was
> compatible. However, to say that he had little to do with the Mercury program
> is simply wrong. As we all know the Redstone is little more than an upgraded
> V2, from the engines to the guidance control.
>
> To say that Von Braun had little to do with Mercury is like saying that
> Henry Ford had little to do with the Model T.

I don't really buy the Von Braun/Ford comparison, but I was not down-
playing VB's role in the SPACE program.  However, the movie over-
played his role in the MERCURY program by leaps and bounds!  Redstone
may have been flying before Atlas, but Mercury wasn't going into orbit
without Atlas, which *was* the primary objective.  And forgotten here is
the Little Joe project, which helped qualify the escape system, among
other things.  My favorite space project, of course!  :-)

I was really focusing on the Mercury spacecraft and THe Right Stuff's
overkill on Von Braun.  Besides the movie made him look like a f**kin'
idiot!  I hated that aspect of the movie.  Things like manual control
were designed in very early in the program, with the astronauts adding
valuable input to the design.  Oh yes, I also got a kick of the "wild-
eyed" German scientist that pushes the two buttons to launch the vehicle.
I think that, even then, the ignition sequence was automated from the last
few seconds of the count.  Anyone remember?

Anyway, Von Braun's cool on my list...

>
> Dennis, University of Alabama in Huntsville
>

Joe Nastasi

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

Date: 28 May 93 17:42:06 GMT
From: Marty Ryba <[e-mail]>
Subject: Voyager Discovers the First Direct Evidence of the Heliopause
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, [e-mail] (Steve Allen) writes:
|> Whenever electromagnetic waves propagate through a medium where there
|> are free charges (read plasma) there is a cutoff frequency below which
|> those waves simply cannot propagate.  They are absorbed.
|> In cgs units this is
|>                   4 pi n_0 e**2
|>         omega_p**2 = --------------
|>                     m
|> where omega_p is the plasma freqency, n_0 is the density of charge,
|> e and m are the charge and mass on each particle, respectively.
|>
|> The density of electrons in earth's ionosphere typically sets a cutoff
|> frequency of about 1MHz.  The density of electrons in the solar wind
|> near earth is less, allowing a lower cutoff for satellites outside
|> earth's environs, but not so low as to see 3kHz.

    Steve is right...in fact the plasma frequency of typical interstellar
gas is in the 1-4 kHz region--the 2-3 kHz signal from the heliopause is the
plasma frequency of the gas there.  The reason the signal can be seen by
Voyager is that the (hot) solar wind is actually *less* dense than that
by the time it gets out to 50 AU.  A heliopause shock of density 0.05
electrons/cm^3 will give a plasma frequency of 2 kHz.

--
Dr. Marty Ryba                     | Generation X:
MIT Lincoln Laboratory             |        Too young to be cynical,
[e-mail]                    |        too old to be optimistic.
Of course nothing I say here is official policy!!!!

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From: Pat <[e-mail]>
Newsgroups: sci.space
Subject: Re: non-solar planets
Date: 1 Jun 1993 12:50:36 -0400
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In article <[e-mail]> [e-mail] (Henry Spencer) writes:
|I wrote:
|>The only extra-solar planets whose existence is beyond dispute are one
|>or two around pulsars...  They're also, last
|>I heard, somewhat puzzling -- the supernova that produces the pulsar
|>should blow them away.
|
|Update:  I'm told, in private mail, that the theorists are sweating a
|bit but have produced one or two plausible ways for pulsars to have
|planets.


How about these two ideas?

Extra-stellar planetary capture?   Wandering planetoid  comes in,  loses
energy to gas shock cloud  and is captured...

or

I heard there is some theoretical evidence to indicate Jovian class
planets  have  Carbon cores  either  Diamond or Fullerenes.
Could this kind of core, survive a supernova?

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End of Space Digest Volume 16 : Issue 655
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