Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no119.txt

Internet Message Format | 1993-07-13 | 17KB

Date: Mon, 17 Aug 92 04:59:57
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #119
To: Space Digest Readers
Precedence: bulk


Space Digest                Mon, 17 Aug 92       Volume 15 : Issue 119

Today's Topics:
                    ACRV/Soyuz P # of Passengers
                 Axisymmetric Navier Stokes Equations
                  Deep-sea Diving on Europa (2 msgs)
                Energiya's role in Space Station assem
          Energya and Freedom and Soyuz ACRV and... (2 msgs)
                               Parsecs?
                  PERSEID STORM OVER EASTERN EUROPE!
                        Private space ventures
                        Tether and Space Junk
                          What about Saturn?
                             What is DCX

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 16 Aug 92 21:58:50 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: ACRV/Soyuz P # of Passengers
Newsgroups: sci.space

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

>    I would think that 62 Atlases with no orders is a pretty
>strong argument for companies taking risk for potential payoff.
>Even more significant was the hundreds of millions invested in
>R&D on the vehicle when the Commercial Atlas startup occurred.

GD and McDonnell Douglas have, between them, invested over a billion $$
of their own money in commercial launchers. they did it because there
was a market and a reasonable chance of getting a decent return. Raising
the money isn't a problem if the market is there.

If we are ever going to go, we need to help make a market, not waste
money on expensive systems like Shuttle.

   Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------250 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 16 Aug 92 21:23:24 GMT
From: Ronald Fedkiw <[e-mail]>
Subject: Axisymmetric Navier Stokes Equations
Newsgroups: sci.space

I'm trying to do a calculation of the full compressible Navier Stokes
equations for flow past an axisymmetric blunt body.
So, I put the equations into axisymmetric form and multiply
through by 1/Jacobian = r = distance from centerline (of axisymmetry).
I need to do this to put the equations back into conservative form for
my method.
The obvious problem is that the equations are no longer valid along
the axis of symmetry (where r = 0). The Jacobian here is infinite.
I'm not quite sure what the implications of an infinite Jacobian are,
but from looking at my equations it becomes obvious that they cannot
be used to solve the flowfield at r=0.

I was wondering what sorts of methods ae in common practice to solve
for the flowfield near r=0.
The solution is important here since this is where the flow passes
through the strongest portion of the shockwave. (It's a normal shock
at r=0 and the heating is high, also this is the where the stagnation
streamline lies.)
So, I need a good method, this might be the most important part of the flow!

Any help is greatly appreciated.

(I've thought about bounding the domain of the grid away from r=0,
 by 1/2 of a grid cell, but what boundry condition would I use?)

Ron Fedkiw

--
Ron Fedkiw ([e-mail])

A plan is made by someone who is sitting and thinking ...
while others are doing.

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

Date: Sun, 16 Aug 1992 18:25:09 +0000
From: Stuart Birkett <[e-mail]>
Subject: Deep-sea Diving on Europa
Newsgroups: sci.space

   Marc Barrett writes.......


  > Many scientists and science fiction writers have speculated
  > about the possibility of life in the depths of the oceans on
  > Europa.

What are the oceans of Europa composed of?

Stuart......


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

Date: 17 Aug 92 03:10:01 GMT
From: Casey Carlton O'Hara <[e-mail]>
Subject: Deep-sea Diving on Europa
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Jeffrey Alan Foust) writes:
>In article <[e-mail]> [e-mail] (Casey Carlton O'Hara) writes:
>>
>>The formula for hydrostatic pressure (the pressure exerted by a fluid
>>due to the weight of the fluid above it) is something like:
>>    p(h) = p(a) + d*g*h
>>where p(h) is pressure at depth h, p(a) is atmospheric pressure, d is
>>depth below surface, and g is acceleration due to gravity.
>
>It looks like you've got some terms confused: you have both d and h
>representing depth below the surface, but no term for the density of the
>fluid.

Whoops. Sure enough, I screwed up in my variables.  There's no way to
type a rho out on this computer, so I decided to use "d" for density,
when I originally had it as depth.  Then I changed depth to "h" for
height, thus confusing the hell out of myself, and probably several others.

Sorry!



--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   __________/  bonz R godz!  ~~~~~~~~~~~~~~~~~
Casey O'Hara              (_|____|___\__________
[e-mail]             _|_|___________)
Disclaimer:  All opinions expressed here are yours.   ~~~~~~~~~~~~~~~~~~~~~~~~~

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

Date: 16 Aug 92 20:29:21 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Energiya's role in Space Station assem
Newsgroups: sci.space

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

>>>Name *one* major military procurement that
>>>proceeded on a fixed price basis with *no* adjustments.

>>The ATF prototype...

>None of these are *procurement* contracts. They are R&D proposals.

LACE, RME, and the associated launches where procurements. However,
if you want other examples, I know of several procurements of HARM
missiles which where delivered at less than the agreed upon price. In
addition, there is the Endeavour purchase as well as several launch
service contracts I know of.

>NASA currently can't sign a guarrantee that it will buy a fixed number
>of anything over a multi-year period because Congress only funds
>NASA year by year.

Nonsense. NASA has a number of agreements for luanchers which streach over
several years. The Air Force which faces even harder constitutional limits
on funding recently bought a ten year supply of Titan missiles.

In addition, we are desling with a station which does need resuply. The
market IS there if NASA will open it up.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------250 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 16 Aug 92 16:06:33 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Energya and Freedom and Soyuz ACRV and...
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>But we will have long duration Shuttles by the time of PMC. So the
>>Shuttle can be crew transport, resupply, material return, and ACRV
>
>In other words, we will simply cut Shuttle utilization in half
>thereby doubling the cost.

No. Launch costs are dominated by support personel costs. Since we
only require one Shuttle launch to serve the function that you
want to service with four separate launches, we save support costs.

Gary

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

Date: 16 Aug 92 20:38:05 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Energya and Freedom and Soyuz ACRV and...
Newsgroups: sci.space

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

>No. Launch costs are dominated by support personel costs. Since we
>only require one Shuttle launch to serve the function that you
>want to service with four separate launches, we save support costs.

The numbers simply don't bear that out. Shuttle fixed costs are enoumous
and for the past 11 years have been pretty independant of the number
of flights.  Therefore the reduced suuttle utilization required by
using Shuttle for ACRV WILL increase costs.

As to my needing more launches, So what? All launches are not equal and
mine cost a fraction of what yours cost. The bottom line is that shuttle
based approaches for station crew rotation and resuply costs about $5 billion
per year and expendable approaches costs about $1 billion per year. The
expendable approaches also offer greater flexability and fallbacks should
one component because grounded.

   Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------250 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 16 Aug 92 13:36:39 GMT
From: Brian Phillips <[e-mail]>
Subject: Parsecs?
Newsgroups: sci.space,sci.physics

In <[e-mail]> [e-mail] (Keith Allan Schneider) writes:

>[e-mail] (Ron Echeverri) writes:

>>In article [e-mail] (Keith Allan Schneider) writes:
>>>...at the distance of one parsec, one astronomical unit subtends an
>>>angle of one arc second.

>>Coincidence.  Remember, one AU is the distance from the Earth to the Sun...

>No, THAT, my friend, is the DEFINITION of a parsec...


   If you're differing on the definition of a word, why not just look the
thing up?

     "A unit of astronomical length based on the distance from earth at which
      stellar parallax is one second of arc and equal to 3.258 light years or
      1.918x10^13 miles.  [PAR(ALLAX) + SEC(OND)]."

      SOURCE:  The American Heritage Dictionary of the English Language,
               New College Edition.

  --Traal the BRAVE
--
   EMAIL (the good, the bad, or the flame) to:  [e-mail]
             "Realism is often misconstrued as pessimism." -- BPP
           "My mailer hates everybody, be sneaky." -- Mary Margaret
    "Take a walk through the looking glass and see the other side." -- BPP

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

Date: 16 Aug 92 21:27:31 GMT
From: [e-mail]
Subject: PERSEID STORM OVER EASTERN EUROPE!
Newsgroups: sci.astro,sci.space,rec.radio.shortwave

PERSEID STORM IN EASTERN EUROPE...

Data from Hungarian meteor observers and several radio amateurs in the USA
and Finland have revealed the strong possiblity that the expected strong
return of the Perseids in 1992 *did* take place. The observations in question
suggest 19-20 UT on Aug 11/12 as the time the outburst occurred. This is
several hours earlier than predicted since the predicition was based on
the assumption that the activity which took place over Japan in 1991 would
recur again at the same position in the Earth's orbit, namely at 138.86
(1950.0). As was pointed out by Marsden if the the shower recurred at
precisely the node of P/Swift-Tuttle the storm would occur several
hours before the 22-23 UT Aug 11/12 shortly after 19 UT, as seems to have
happened. This is **very** strong evidence to suggest that P/Swift-Tuttle is
very nearby and searches for the comet should certainly go into high gear.
This outburst occurred at 138.74 (1950.0) and if it recurs again within
a few tenths of degrees of this position then we can expect a nice meteor
shower in 1993 on Aug 12 at about 1-2 UT. This means North America might
catch some of the activity early in the evening and the moon will be only
4 days from new!!
Since many details are still missing it is *imperative* that observers either
radio or visual who have data in the interval 18-20 UT report it as soon as
possible so a complete picture of what happened can be constructed.
Further details can be found on IAUC 5586.

*****************************************************************************
Peter Brown   [e-mail]
North American Section - International Meteor Organization (IMO)
*****************************************************************************

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

Date: 16 Aug 92 18:41:08 GMT
From: Craig Powderkeg DeForest <[e-mail]>
Subject: Private space ventures
Newsgroups: sci.space

[e-mail] (dann cutter) writes:
   Could anybody out there please tell me the current status of the private
   space industry world wide. What comapnies exist... what they have done...
   thanks

The only semi-serious private space venture I know of, was Bob Truax's.  Truax
is the fellow who built Evil Knievel's steam rocket to jump the Snake River
canyon.

He used to be based in Saratoga, CA -- right here near Stanford.  Had a few
rocket engines, plans for a `volksrocket'.  Was selling suborbital rides
into space for $100,000 apiece -- but didn't get enough takers (I don't think
he actually collected his $10^5 from anyone) and couldn't afford to launch
the prototype.  I can't recall whether it ever got finished or not.

The idea was to have sea launch and recovery to make it cheap, and to adapt
existing parts rather than build custom ones to build the craft.   A few
years ago, the Air Force bought the prototype from him for a cool 3/4 of a
million dollars -- enough to buy a house in Palo Alto!

You can read a bit about Truax in `Great Mambo Chicken and the Transhuman
Condition' by Ed Regis, at a bookstore near you.

Are there any other people around who've come as close to success (defined
as a private launch) as even Truax did?

[It bugs me that there are people like H Ross Perot, who themselves
have enough cash to finance their own space programs, but that none, so
far, has underwritten one.]
--
Craig DeForest:  [e-mail]  *or*  [e-mail]

"So, if you guys make a living looking at the SUN, why do you spend so much
        time at the SYNCHROTRON, working UNDERGROUND at NIGHT?"

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

Date: 17 Aug 92 01:15:47 GMT
From: Robert Bunge <[e-mail]>
Subject: Tether and Space Junk
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (clifford bettis) writes:
>
>I have been waiting to see this issue discussed: in the event of
>serious difficult with the tethered satellite experiment, I understand
>that one option was to cut the tether. Wouldn't a 20 km cable in orbit
>be the environmental equivalent of a drift net for space craft and
>pose an unacceptable hazard?
>Cliff Bettis

A follow up to the above question is what happens when a 12 to 20 or
so mile-long tether starts to re-enter the Earth's atmosphere?  Aren't
the Russians planning on flying a tether experiment and cutting it at
the end of the experiment?  Would a long tether burn up?

Bob Bunge
[e-mail]

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

Date: 16 Aug 92 22:35:53 GMT
From: Gerald Cecil <[e-mail]>
Subject: What about Saturn?
Newsgroups: sci.space

>[e-mail] (Chase R. Laurendine) writes:
> ...  With all the interest in using Energiya's payload capacity for
> SSF and the fond memories of the Saturn V program, I am curious to know how
> the payload capacities of the two compare.

The heaviest lift variant of ``revitalized'' Saturn V that has been discussed
here would use STME's for the 2nd stage, to put ~140 metric tons into LEO.
Energiya can put up ~150 metric tons with 4 strap-ons and ~235 metric tons
with 6, but only into high inclination orbits.  Payloads to 28.5 degs are
10-15% of those quoted above.
--
Gerald Cecil 919-962-7169  Dept. Physics & Astronomy
U of North Carolina, Chapel Hill, NC 27599-3255 USA
-- Intelligence is believing only half of what you read; brilliance is
   knowing which half. ** Be terse: each line cost the Net $10 **

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

Date: Sun, 16 Aug 92 18:46:24 CDT
From: [e-mail] (Mike Evert)
Subject: What is DCX

This question is for Allen Scherzer:

What is DCX?  A previous acronyms posting tells me that is the Delta Clipper.
What is it designed to do and how far along is it to being operational?

I'm new to this news group so if DCX has been discussed before, please forgive
me.

Thanks,

Mike

--
+----------------------------------+---------------------------------------+
|  Mike Evert                      | "You are helplessly hypnotized.  You  |
|  Internet: [e-mail] |  will believe everything I tell you.  |
|    Delphi: [e-mail]   |  This quoted message does not exist." |
+----------------------------------+---------------------------------------+

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

End of Space Digest Volume 15 : Issue 119
------------------------------