Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_2/V16NO251.TXT

Internet Message Format | 1993-07-13 | 22KB

Date: Tue,  2 Mar 93 05:23:25
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #251
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue,  2 Mar 93       Volume 16 : Issue 251

Today's Topics:
                 Blimp/Rover Ideas.. Mars and beyond!
                      Bullets in Space (2 msgs)
               Can Cassini Titan Probe float? (2 msgs)
                Galileo Earth-Moon Animation (2 msgs)
                  New name for Fred (Fed?): Results
       New name for Fred (Fed?): Results, SS Courage (F-Troop).
                          Refueling in orbit
    Reliable Source says Freedom Dead, Freedom II to be developed
                   Russian Space Mirror Deployment
                        Stupid Centaur Tricks
              What we need to do (was: SSF Resupply...0

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

Date: 28 Feb 93 18:59:12 GMT
From: [e-mail]
Subject: Blimp/Rover Ideas.. Mars and beyond!
Newsgroups: sci.space

Idea for a rover combined with a balloon/blimp.

Maybe have the blimp travel around and have either a direct feed tether to the
rover? or some form of radio control of the rover or rovers.. Use the blimp as
a command post for a multi-rover probe of Mars and maybe elsewheres..

For a gas giant, have the blimp act as a mother ship and some small "blimps" as
daughter ships/rovers...


Michael Adams
NSMCA@ACAD@.ALASKA.EDU
I'm not high, just jacked

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

From: Frank Crary <[e-mail]>
Subject: Bullets in Space
Newsgroups: sci.space

Nntp-Posting-Host: ucsu.colorado.edu
Organization: University of Colorado, Boulder
References: <[e-mail]>
Date: Sun, 28 Feb 1993 17:16:10 GMT
Lines: 24
Source-Info:  Sender is really [e-mail]
Source-Info:  Sender is really [e-mail]

In article <[e-mail]> [e-mail] (Brandon France) writes:
>What would happen if an astronaut was in a geostationary orbit and fired
>a rifle directly toward the earth?  What path would the bullet take?
>Would the bullet actually hit the earth or would it assume some orbit?

Since you said geostationary orbit, I'd have to know what sort of
a rifle: Geostationary orbital velocity is roughly 2500 m/s. Since
rifle muzzel velocities range from ~300m/s up to 1200 m/s, there is
a wide range of possibilities. I don't think any would hit the
Earth, unless the rifleman were more subtle: If he fired 90 degrees
off from the Earth (i.e. directly west) the all the rifle's power
would go into reducing the bullet's orbital velocity. That would
get the bullet as close as possible to the Earth, but I'm still not
sure if it would hit...

(By the way, the rifleman wouldn't fly backwards under the recoil, as
is often thought: The linear momentum transfer is quite small and
the shooter's final velocity would be under 1 m/s (3.6 km/hr). The
angular momentum, however, is very significant: If he fired the rifle
from the shoulder, he'd wind up spinning at something like 50 rpm...)

                                                   Frank Crary
                                                   CU Boulder

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

Date: Sun, 28 Feb 1993 17:28:47 GMT
From: Frank Crary <[e-mail]>
Subject: Bullets in Space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (George Hastings) writes:
>    You would have succeeded in putting the bullet (and
>yourself) into elliptical rather than circular orbit.
>    Question back to you: if the bullet in its new orbit
>spends part of its time travelling faster than the original
>geo-synchronous speed and part of the time travelling slower
>than geo-synchronous speed, is its new orbital period still 24
>hours?

An object's orbital period depends only on the semi-major axis of
it's orbit, and the semi-major axis in turn depends only on
the object's energy. Since the shot increased the bullet's energy
(because of the direction in which it was fired), the bullet's
semi-major axis will be reduced and therefore it's orbital period
will be shorter. There is some specific angle, (theta =
2* arcsin(Vbullet/2*Vorbit). If the shooter fires this many degrees
west of the Earth, the bullet's energy will be unchanged, and
it will have a period of 24 hours still. Of course, that means the
bullet will come back and hit the shooter exactly 24 hours later
(assuming he hasn't moved...)

                                                 Frank Crary
                                                 CU Boulder

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

Date: 28 Feb 1993 18:15 UT
From: Ron Baalke <[e-mail]>
Subject: Can Cassini Titan Probe float?
Newsgroups: sci.space

[e-mail] (Jeff Bytof) writes:

>Will the basic design of the Cassini Titan Probe allow it to
>float if it lands on a liquid medium?

I believe so.  It will also have instruments to determine if the surface
it lands on is solid or liquid.

>How long will Cassini be in contact with the Titan Probe after
>it enters the atmosphere?

About 2.5 to 3.5 hours.

>Cassini goes on to Saturn orbit, correct?

The probe will be dropped off at Titan after orbit insertion during the
first orbit.  There is a contingency plan to use the second orbit if the
first orbit opportunity is missed for some reason.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | If you don't stand for
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/  |_|/       |_____|/                     | for anything.

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

Date: Sun, 28 Feb 1993 18:58:48 GMT
From: Josh Hopkins <[e-mail]>
Subject: Can Cassini Titan Probe float?
Newsgroups: sci.space

[e-mail] (Ron Baalke) writes:

>>Cassini goes on to Saturn orbit, correct?

>The probe will be dropped off at Titan after orbit insertion during the
>first orbit.  There is a contingency plan to use the second orbit if the
>first orbit opportunity is missed for some reason.

Why are they releasing Huygens after orbit insertion?  Gallileo releases its
probe beforehand, if I recall correctly, so that the rocket motor doesn't have
to decelerate the probe mass.  Is Titan entry harder so that they require a
lower velocity?  If so, why?

--
Josh Hopkins                                          [e-mail]

    You only live once.  But if you live it right, once is enough.
            In memoria, WDH

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

Date: 28 Feb 1993 18:20 UT
From: Ron Baalke <[e-mail]>
Subject: Galileo Earth-Moon Animation
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, [e-mail] (David Knapp) writes...
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>>The animation was formed from 46 images taken by Galileo
>>spaecraft shortly after its Earth flyby on December 16, 1992, and is in a
>>compressed PICT format to be used with the NIH Image software on the Macintosh.
>>Efforts to convert the animation to other formats is currently in progress.
>
>Can someone with the proper resources put this into mpeg or gl format for
>the rest of the computer world?
>
Conversion to other formats is already underway.  Also, someone notified me
that they were able to run the animation under Quicktime.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | If you don't stand for
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | something, you'll fall
|_____|/  |_|/       |_____|/                     | for anything.

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

Date: Sun, 28 Feb 1993 18:10:24 GMT
From: Leigh Palmer <[e-mail]>
Subject: Galileo Earth-Moon Animation
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> David Knapp,
[e-mail] writes:
>Can someone with the proper resources put this into mpeg or gl format for
>the rest of the computer world?

What could you possibly mean? We *are* The Rest Of The Computer World.

(Intercalate 144-point smiley here.)

Leigh

(I downloaded it, but I've not run it yet.)

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

Date: Sun, 28 Feb 1993 12:55:55 GMT
From: Paul Carter <[e-mail]>
Subject: New name for Fred (Fed?): Results
Newsgroups: sci.space

In an previous post, I wrote:
 :First there was Space Station Freedom, then cutbacks led to Fred.
 :What name should be given to the newly announced redesign of the redesign ?
 :Ideas for some candidates:
 :MacFred   - Son of Fred
 :Fre       - allows for three more redesigns: "Fr", "F" and ""
 :Freddie   - there was some Horror movie character by this name
 :FCFG      - Freedom come, Freedom go ( sung to the tune of the song of the
 :            same title ).
 :Fort Tune - Sounds similar to Freedom, but costs more.
 :Freeom    - Freedom without a truss.
 :
 :Post your ideas to me, I'll collate them and put up a summary
 :of candidates. If there's enough interest, a vote can be organised.
 :My mail address: [e-mail]

*******Here's the responses so far********

How about "Leeway"? Its not full freedom, but its a start.
        - Brian S. Thorn ([e-mail])


Name it after a congressman/senator and your funding will grow rather
than be cut.
Name it after Martin Luther King and wait for taxfree donations to roll in
        - Jerry Laplante ([e-mail])


we joked about how Freedom became Fred cuz it was too short after defunding
to paint the whole name on... the next joke was that it became ''Ed'' next..
my joke to him last week was that it became ''Mir'' =D
        - Cheryl Douglas & Eric Schneider ([e-mail])


How about 'FED' to reflect the group whose interests are served by it?
        - Tom McWilliams (Tommy Mac) ([e-mail])


Luv 'em - keep 'em coming ...
Regards,

--
     P A U L        P A U L         P A U L       P A U L         P A U L
     C A R T E R   C A R T E R    C A R T E R    C A R T E R      C A R T E R
      3d signature 3d signature  3d signature      3d signature    3d signature
Focus lines:            |             |

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

Date: Sun, 28 Feb 1993 18:41:14 GMT
From: [e-mail]
Subject: New name for Fred (Fed?): Results, SS Courage (F-Troop).
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Paul Carter) writes:
> In an previous post, I wrote:
>  :First there was Space Station Freedom, then cutbacks led to Fred.
>  :What name should be given to the newly announced redesign of the redesign ?
>  :Ideas for some candidates:
>  :MacFred   - Son of Fred
>  :Fre       - allows for three more redesigns: "Fr", "F" and ""
>  :Freddie   - there was some Horror movie character by this name
>  :FCFG      - Freedom come, Freedom go ( sung to the tune of the song of the
>  :            same title ).
>  :Fort Tune - Sounds similar to Freedom, but costs more.
>  :Freeom    - Freedom without a truss.
>  :
>  :Post your ideas to me, I'll collate them and put up a summary
>  :of candidates. If there's enough interest, a vote can be organised.
>  :My mail address: [e-mail]
>
> *******Here's the responses so far********
>
> How about "Leeway"? Its not full freedom, but its a start.
>         - Brian S. Thorn ([e-mail])
>
>
> Name it after a congressman/senator and your funding will grow rather
> than be cut.
> Name it after Martin Luther King and wait for taxfree donations to roll in
>         - Jerry Laplante ([e-mail])
>
>
> we joked about how Freedom became Fred cuz it was too short after defunding
> to paint the whole name on... the next joke was that it became ''Ed'' next..
> my joke to him last week was that it became ''Mir'' =D
>         - Cheryl Douglas & Eric Schneider ([e-mail])
>
>
> How about 'FED' to reflect the group whose interests are served by it?
>         - Tom McWilliams (Tommy Mac) ([e-mail])
>
>
> Luv 'em - keep 'em coming ...
> Regards,
>
> --
>      P A U L        P A U L         P A U L       P A U L         P A U L
>      C A R T E R   C A R T E R    C A R T E R    C A R T E R      C A R T E R
>       3d signature 3d signature  3d signature      3d signature    3d signature
> Focus lines:            |             |

How about Space Station Courage, from Fort Courage from TV's F-Troop..

Michael Adams
NSMCA@ACAD@.ALASKA.EDU
I'm not high, just jacked

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

Date: Sun, 28 Feb 1993 19:58:21 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Refueling in orbit
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>Allen, have you been getting enough sleep lately?  Go back and read my article
>very slowly and very carefully, pronouncing each word.  You are drawing
>conclusions that have absolutely nothing to do with what I wrote.

Have YOU been getting enough sleep? Your treating the teather like it was
critical to the effort and that it couldn't be done if teathers fail.

As I said in the paragraph you deleted this is not the case. If teathers
work, great. If not, then a small solid kick motor will do the same thing
very inexpensively.

  Allen


--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------107 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 28 Feb 93 21:32:58 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Reliable Source says Freedom Dead, Freedom II to be developed
Newsgroups: sci.space

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

>Well Allen if you read Space News this week you will see that it is the
>redesign that has gotten them in a lot of trouble.  I can see this as
>the inevitiable result of Congress trying to design a space station
>instead of the engineers.

I don't think you read all of Space News Dennis. Check out the story
on page 3. It seems that Morehouse at Reston had been sending memos to
NASA senior management claiming that WP 2 was out of control and was
being poorly managed. These memos where written a full 10 months before
the story broke.

NASA has plenty of warning that trouble was brewing but decided not
to do anything. Maybe if NASA has listened to Morehead instead of
trying to sweep it under the rug WP 2 wouldn't be a billion $$ over
budget.


Can't blame this on Congress.

>>Um... the Russians refuel in orbit with zero eva or even astronaut time
>>spent. It is done with an automatic system.

>How about giving some details on this worderful system.

There have been several postings on this since. I assume you saw them.
Let me know if you didn't.

If you did, why can't we do the same and save lots of $$?

>Since you have
>a resource such as the Shuttle that has the carry back capability that it
>has, it seems to me that the replaceable units are a good idea.

If one ignores the cost, perhaps. But ignoring costs is one reason we
are in this mess in the first place.

>It obviously takes less time to implement, which will save a dime or two
>of operations costs.

The US system will take hours of astronaut time at huge expense to
replace thrusters. In addition, you are lifting twice the mass in a
vehicle which costs three times as much as the alternatives.

There is no way you can justify ANY cost savings with the current method.
NASA would be hard pressed to come up with a more expensive one if it
tried.

>>Bottom line Dennis is the things you think save EVA time actually cost
>>more.

>How about some comparative numbers on this Allen instead of a blanket
>statement with no facts? I will gladly agree with you IF you can do this.

Fine. Let's look at the cost of replacing thrusters the way it will be
done VS automatic refueling:


                      Manual                Automatic
1. Launch costs:       $500M (shuttle)        $75M  (2 deltas or an Atlas)
2. Astronaut time:       $1M (guess)            0   (its automatic)
      TOTAL:           $501M                  $75M

Now figure about 45 replacement flights and we have a cost of $22.545B
for the current method VS $3,375B for automatic. Note that this assumes
commercial putchase of all components and services. It does not include
any price break for the 45 launchers we will buy (which will offer a lot
more savings).

>It seems to me just common sense that by using the Canadaarm you could
>chage out the module without ANY EVA time.  That is my understanding of
>how it will work. Any correction to this?

Still requires several hours of hugely expensive Astronaut time.

>As the Space News article shows, congresses direction is responsible for
>a quick fix redesign that is now 1 billion dollars over budget.

The story I saw said NASA ignored repeated warnigns from the Reston office
and allowed the problem to grow into a $1B overrun.

Can you justify NASA's inaction when they knew WP 2 was out of control?

     Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------107 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 28 Feb 93 18:52:50 GMT
From: SETH WATKINS <[e-mail]>
Subject: Russian Space Mirror Deployment
Newsgroups: sci.space

A New York Times article on Friday, February 5, 1993 mentioned that the Russian
space mirror was deployed through the use of an electric motor which spun a drum,
and employed centrifugal force to unfurl the space mirror like a Japanese fan.
Does anyone have details on this deployment method, and on the specifics of the
Russian deployment system?

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

Date: Sun, 28 Feb 1993 16:19:44 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Stupid Centaur Tricks
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Phil G. Fraering) writes:
>[e-mail] (Dave Michelson) writes:
>
>>Centaur continues to evolve.  AW&ST recently carried an item about General
>>Dynamics looking for funding to develop a single engine version of the
>>Centaur to increase both payload (marginally) and reliability.  I guess
>>price would also decrease slightly as well since it's easier to test and
>>verify one engine than two.
>
>
>I don't understand why it's more reliable to have a single engine than
>two engines with a gimballing system that would allow it to function
>on one engine.
>
>I guess they're just into newspeak (half the engines, half the chance
>of failures!).

Indeed. An engineering maxim is the fewer parts you have, the fewer
can fail. In the last two Centaur failures, it's been a failure of
one of the two engines to ignite. Neither mission could succeed with
one engine out, not enough thrust. Fewer parts generally translate
into cheaper production costs too.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 28 Feb 93 21:44:07 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: What we need to do (was: SSF Resupply...0
Newsgroups: sci.space

In article <1mpa9h$[e-mail]> [e-mail] (George William Herbert) writes:

  >Allen is wrong because he treats NASA as if it were a small business
  >operating in a free market, and it isn't. It is not at all clear to
  >me that it should be either.

>That's a flaw of Allen's posts, agreed.  He's pointing out idealized
>technical solutions in what currently is a massively muddled technical,
>political, social, economic, and media problem.  There is nothing wrong
>with doing this: a reasonable goal for a space program might be to
>change its external environment so that it can operate more reasonably
>at the technical level that it should be most concerned with.

Exactly. The problems with space are not technical but political and
social. The ideas are out there and they will work. Not only that,
they will work for far less cost. We don't even need more money; all we
need do is spend the money we do spend better.

>Deciding to do so is a necessary prerequisite for implimenting
>teh "quick technical fixes" that come up so often here, and is rarely
>discussed because it's so massive a problem that it often can't be
>solved except by top-down fiat, rare in this age.

Yet there will never be significant progress until we to address those
problems.

And we can make those changes. We have in the past enacted legislation
forcing NASA to spend money better. We can do more.

  Allen


--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------107 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

End of Space Digest Volume 16 : Issue 251
------------------------------