Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_2/V11_286.TXT

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Subject: SPACE Digest V11 #286

SPACE Digest                                     Volume 11 : Issue 286

Today's Topics:
               Re: Interstellar travel
         Re: Apollo 13, STS-1, Vostok 1 anniversaries
           Re: Questions about the Voyagers
       NASA Headline News for 04/18/90 [Afternoon] (Forwarded)
          Re: Pegasus launch from Valkyrie  (or ...
           Materials (Was: Re: Energy consumption)
           Re: space news from March 12 AW&ST etc.
              Re: Fermi Paradox
----------------------------------------------------------------------

Date: 18 Apr 90 18:33:13 GMT
From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Interstellar travel

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
>I don't have references, but studies on Interstellar travel have looked
>at the possibility of using a dust or gas cloud put in front of you while you
>are coasting to cut down on the amount of gas or dust likely to collide
>with you.

Maintaining such a cloud during the long cruise phase is costly in mass.
Project Daedalus just used armor on the front for cruise, but did in fact
use a smoke cloud for the actual encounter with the target solar system.
Solar systems are very dusty places at 15% of the speed of light...
--
With features like this,      |     Henry Spencer at U of Toronto Zoology
who needs bugs?               | uunet!attcan!utzoo!henry [e-mail]

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

Date: 18 Apr 90 17:37:16 GMT
From: hplabsb![e-mail]  (David Smith)
Subject: Re: Apollo 13, STS-1, Vostok 1 anniversaries

In article <[e-mail]> [e-mail] (David Hallidy) writes:
>the Service Module exploded, causing them to have to limp around the
>Moon and back to Earth, using the Oxygen on board the Lunar Lander
>and an ingenious fabrication of some sort using Lithium Hydroxide, which
>was on board, to give them the Oxygen they needed for the return.

The lithium hydroxide was for removing carbon dioxide from the air.
The lunar module did not have enough cartridges for the time it would take
to get back, and naturally ;-) the cartridges for command and lunar modules
were incompatible.  So they adapted the CM cartridges to the LM with duct
tape.
--
    David R. Smith, HP Labs    | "It is said that St. Patrick drove the
    [e-mail]    | snakes out of Ireland.  They were last seen
    [phone]        | selling junk bonds."  -- Johnny Carson

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

Date: 18 Apr 90 20:53:37 GMT
From: usc!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!sp20.csrd.uiuc.edu![e-mail]  (James R. B. Davies)
Subject: Re: Questions about the Voyagers


In article <[e-mail]>, [e-mail] (Henry
Spencer) writes:
|> In article <[e-mail]>
[e-mail] (David Solana) writes:
|>
|> >    * Why didn't they visit Pluto? ...
|>
|> Because it was nowhere near their flight paths, which were fixed by the
|> use of gravity-assist maneuvers from planets further in.
|>

One of the Voyager mission planners gave a talk here recently.  He said
that Voyager 1 could have gone on to Pluto after Saturn (and some of the
ground crew wanted it to, including the speaker), but to do so would
have meant omitting the close fly-by of Saturn's moon Titan.

To go on to Pluto from Saturn, a gravity assist from Saturn would have
been possible.  Titan was on the wrong side, so they couldn't do both.

At the time Titan was considered to be a good candidate for the
most interesting body in the solar system (other than Earth, of course)
since it was known to have an atmosphere, wasn't a gas giant, etc.
In fact, it turned out to be relatively bland and featureless.
Another factor in the decision was that the trip to Pluto would
have been quite long, and the Voyager might not have lasted that long.

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

Date: 18 Apr 90 21:32:41 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 04/18/90 [Afternoon] (Forwarded)

-----------------------------------------------------------------
Wednesday, April 18, 1990             Audio Service: 202/755-1788
-----------------------------------------------------------------
This is a 1:00 p.m. update of NASA Headline News for Wednesday,
April 18....

Space shuttle managers have announced the target date for the
launch of the STS-31 space shuttle mission has been advanced one
day to Tuesday, April 24.  The launch opportunity period on the
24th will begin at 8:31 a.m., EDT.

                        *              *
Controllers at Jet Propulsion Laboratory report all subsystems
are operating satisfactorily aboard the Venus-bound Magellan
spacecraft.  It's traveling at a velocity of over 35-thousand
miles per hour relative to the planet and now is just 34 million
miles away.  An attitude reference test was successfully
completed last week, star calibrations have gone well and two
Deep Space Network checks have been successful.

                        *              *

Meanwhile, the Galileo spacecraft is operating extremely well.
The first four-day portion of a complicated trajectory maneuver
was completed last week.  The second part of the maneuver is
scheduled for mid-May.  Several more corrections will be made
before the spacecraft's gravity assist flyby of Earth in early
December.
                        *              *

Scientists are puzzled with some data from the Cosmic Background
Explorer Satellite launched last November, but also pleased with
a visual byproduct.  Wire service reports say scientists meeting
in Washington, D.C., are confounded by data which indicate an
unexpectedly smooth and uniform expansion of the universe and no
indication of other cataclysmic events that had been theorized.
Michael Hauser, of NASA's Goddard Space Flight Center says, "The
quandry is deepening".  A color image of the galactic center of
the Milky Way was released yesterday free of cosmic dust that has
obscured our galaxy's center previously.

                        *              *

President Bush was criticized yesterday by some western European
delegates to a White House conference on global warming for not
taking a stronger stand on the issue.  The President has called
for more data before taking drastic control efforts which could
have serious effects on the world economy.








_________________________________________________________________
Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are EDT.

Thursday, April 19.....

    11:30 a.m.     NASA Update will be transmitted.


Friday, April 20....

    10:30 a.m.     STS-35 astronaut news conference from
                   Johnson Space Center.


Sunday, April 22.....

     1:00 p.m.     STS-31  crew arrival at KSC


Monday,  April 23.....

     9:00 a.m.     STS-31 Countdown Status Report

    10:00 a.m.     APU/telescope Status Report

    11:00 a.m.     Prelaunch News Conference


Tuesday, April 24......

      4:00 a.m.    STS-31 mission launch coverage begins.

NOTE:  During the STS-31 mission television highlights will be
transmitted on Satcom F1R, transponder #13 at 12 midnight, EDT,
for the benefits of TV stations and educational institutions in
Alaska and Hawaii.

All events and times are subject to change without notice.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
EDT.
-----------------------------------------------------------------
A service of the Internal Communications Branch, NASA Hq.

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

Date: 18 Apr 90 18:54:44 GMT
From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Pegasus launch from Valkyrie  (or ...

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>How about the concord?

Concorde, please.  Not impossible, but Concorde is not built for dropping
things, and it would take quite a bit of work to fit it for the job and
test things out properly.  (Proper separation of a dropped object at
supersonic speed is not to be taken for granted -- fighter designers work
fairly hard on this and test it at great length.)

A more fundamental problem is that it's an expensive bird to operate --
the current ones make money (yes, they do, they were subsidized once but
not any more) only by having very high fares -- and none of the existing
ones is for sale.
--
With features like this,      |     Henry Spencer at U of Toronto Zoology
who needs bugs?               | uunet!attcan!utzoo!henry [e-mail]

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

Date: 18 Apr 90 06:50:15 GMT
From: agate!earthquake.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Materials (Was: Re: Energy consumption)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>That's not what he said.  In any case, many newer space vehicles probably
>*will* use old alloys.  Hermes will be mostly aluminum, for example, not
>titanium like the shuttle.  The fact is, tried and true alloys are quite
>adequate for spaceflight unless you are pushing the state of the art for
>its own sake, e.g. NASP.

Umm, Henry, did'ja look before this posting? :-) [sorry]
The shuttle is good ole Aluminum alloys, much of it garden variety 2024 and
7075 ...
Which is not to detract from the general tone of your posting, which was that
the shuttle pushed technology all over.  It did, in almost all ways, and in
retrospect building it out of titanium would have been a great idea because
it would have ended up a lot lighter with a corresponding higher payload, all
for a fraction of the total development cost...an example of bad early design
economics failure.


*******************************************************************************
George William Herbert              JOAT For Hire: Anything, Anywhere: My Price
   UCB Naval Architecture undergrad: Engineering with a Bouyant Attitude :-)
-------------------------------------------------------------------------------
"Who?" the man managed.                    Whip me, Beat Me, Make me learn C...
"The Rastafarian Navy," Case said,         ++++++++++ [e-mail]  OR
"...and all we want is a jack into your    ========== [e-mail] OR
custodial system." -neuromancer            """""""" [e-mail]

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

Date: 18 Apr 90 17:05:34 GMT
From: zaphod.mps.ohio-state.edu!rpi!brutus.cs.uiuc.edu!samsung!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: space news from March 12 AW&ST etc.

In article <[e-mail]> [e-mail] (maurice.r.baker) writes:
>> Soviets say that the first Buran orbiter probably will not fly again,
>
>Does anyone know how many orbiters there are in the USSR shuttle "fleet"?
>Is this really saying that there is a new orbiter design under construction
>now...

There is at least one more under construction.  Reports vary on the eventual
total size of the fleet, probably because they aren't sure yet.
--
With features like this,      |     Henry Spencer at U of Toronto Zoology
who needs bugs?               | uunet!attcan!utzoo!henry [e-mail]

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

Date: 18 Apr 90 18:58:05 GMT
From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Fermi Paradox

In article <[e-mail]> [e-mail] (Mike Butts) writes:
>On the subject of relative time, go read "Dragon's Egg" by Dr. Robert Forward.
>Intelligent life evolves on the surface of a neutron star, based on nuclear
>chemistry, not that lazy, slow, electron-shell stuff we use.  They live about
>10^6 times faster than we do.  It's a great read, and backed up quantitatively
>in the appendix.  In this context it's an instructive example on how alien
>other life forms might be...

Actually, Forward himself admits that his neutronic life wouldn't work.
The "plants" that are the base of the food chain supposedly run on the
temperature difference between the crust and the sky, and he says that
thermodynamically this doesn't work well enough to fuel neutronic life.
I agree that it's a good book and relevant too.
--
With features like this,      |     Henry Spencer at U of Toronto Zoology
who needs bugs?               | uunet!attcan!utzoo!henry [e-mail]

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

End of SPACE Digest V11 #286
*******************