Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_6/v16no635.txt

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Date: Fri, 28 May 93 11:08:05
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #635
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Space Digest                Fri, 28 May 93       Volume 16 : Issue 635

Today's Topics:
     August Meteor Shower May Threaten Earth Satellites (2 msgs)
             Boeing TSTO concept (sort-of long) (2 msgs)
                             Comet 1993e
              Detecting planets in other system (3 msgs)
                  Hey Sherz! (For real!) Cost of LEO
                          Moon Base (2 msgs)
                        NASA CD-ROM add/price
                      Planets around other stars
                          The crew is toast
           Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
    Voyager Discovers the First Direct Evidence of the Heliopause

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

Date: 26 May 93 19:02:00 GMT
From: Stan Ryckman <alden!sgr>
Subject: August Meteor Shower May Threaten Earth Satellites
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail] (Ron Baalke) writes:

[stuff deleted]

>Notes

>1.
[deleted]
>
>2. The observed activity of a meteor shower is measured in terms of
>'Zenithal Hourly Rate' (ZHR). The normal peak ZHR of the Perseids is
>around 100. The Leonid storm in November 1966 had a ZHR of 100,000
>for a period of 2040 minutes.
                 ^^^^^^^^^^^^
Uh, that's 34 days.  How long was it _really?_


Stan.
--
X-Obligatory-.sig
    Stan Ryckman   [e-mail]

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

Date: 26 May 93 19:30:39 GMT
From: Stan Ryckman <alden!sgr>
Subject: August Meteor Shower May Threaten Earth Satellites
Newsgroups: sci.space

In article <[e-mail]> I wrote:
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:

>>            The Leonid storm in November 1966 had a ZHR of 100,000
>>for a period of 2040 minutes.
>                 ^^^^^^^^^^^^
>Uh, that's 34 days.  How long was it _really?_

Sorry, I meant 34 hours.  This newsreader won't let me cancel things.
But I seem to remember it was much less than one day, so the question
stands.

Stan.
--
X-Obligatory-.sig
    Stan Ryckman   [e-mail]

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

Date: Wed, 26 May 1993 20:26:08 GMT
From: Fred Cordes <[e-mail]>
Subject: Boeing TSTO concept (sort-of long)
Newsgroups: sci.space

>>The B-58 wasn't capable of Mach 3 even in a dash, and neither the SR-71
>>nor the X-15 was made of aluminum.  (The SR-71 was mostly titanium, and
>>the X-15 used titanium for its *low-temperature* structure plus various
>>refractory metals for the hot stuff.)

I've been reading "Edge of Space" by Milt Thompson, about the X-15 program.
The book was published in 1992 by Smithsonian Press and details the
program from an insider pov. Mr. Thompson was one of the research pilots
and a NASA employee. He points out that Inconel, a nickel-steel alloy,
was used to construct the framework and outer skin of the 3 aircraft.

There are several accounts and photos that support the author's claim that
the X-15 was a "tough old bird". There is also a photo of the leading edge
of the ventral fin on the plane that made the Mach 6.7 speed run. There's
a large hole in the skin and lots of damage around it, indicating that
the X-15 was flown to its limits (beyond the target speeds) during the
tests.

I've been looking for some more popular press books about hypersonic
aircraft development since the X-15 era, and would welcome posts to the net
about the subject. There are certainly books about the shuttle, but not
much about it as a hypersonic aircraft. I find the AIAA technical papers
pretty intimidating and most public library books on the subject are X-15
related (a few) or shuttle books focusing giving very superficial technical
info.

Fred Cordes

--
 Fred Cordes                {uunet, ucsd, sun}!megatek!cordes
 619-455-5590 ext 2594                    [e-mail]
 Megatek Corporation  9645 Scranton Rd.  San Diego, Ca.  92121

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

Date: 26 May 1993 17:40:18 -0400
From: Pat <[e-mail]>
Subject: Boeing TSTO concept (sort-of long)
Newsgroups: sci.space

Mary shafer,  kindly sent me the papers from the 30'th?
anniversary of the X-15 flight.   Maybe she has a few,
these were serious historical reviews, from a day long conference.

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

Date: 26 May 93 14:02:33
From: Steinn Sigurdsson <[e-mail]>
Subject: Comet 1993e
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:

   Well, if P/C-S started out at 5km, it could make 100+ 1 km fragments,

Ack, that's P/S-L, I'm clearly stuck months behind the state of the
art...

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

Date: Wed, 26 May 1993 20:53:58 GMT
From: Robert Casey <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail] (Thomas Clarke) writes:
>In a recent issue of Science there is a discussion of a project
>to look for MACHOs (Massive Compact Halo Objects - things like
>planets, brown dwarfs, or even black holes in the galactic halo
>that might account for some of the missing mass).  The scheme for
>detecting MACHOs is to look for a micro-gravitational lensing event
>as the MACHO passes in front of a distant star.  To make the
>statistics workable they have put together a 64 million (!!!) pixel

>CCD which will be mounted on an otherwise little used 50-odd inch
>worn-out telescope.  The CCD will then stare at the large Magellenic
>Cloud (LMC) to look for microlensing events.  They expect a
>jupiter-sized object to enhance a stares brightness for a day or two,
>a week or two for dwarfs, and possibly months for a black hole.

I vaguely (yes, again, I got a vague memory!) remember seeing in Sky and
Telescope 6-12 months ago a brief news note saying a suspected micro
lens event was seen.  Suspect a Jupiter planet in a closer galaxy lensed
a star in a further galaxy.

But how do you prove/verify/test this?  Not really repeatable, at least
not the same objects again.

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

Date: Wed, 26 May 1993 21:56:00 GMT
From: Leigh Palmer <[e-mail]>
Subject: Detecting planets in other system
Newsgroups: sci.space,sci.astro

In article <[e-mail]> Thomas Clarke,
[e-mail] writes:
>In a recent issue of Science there is a discussion of a project
>to look for MACHOs (Massive Compact Halo Objects - things like
>planets, brown dwarfs, or even black holes in the galactic halo
>that might account for some of the missing mass).  The scheme for
>detecting MACHOs is to look for a micro-gravitational lensing event
>as the MACHO passes in front of a distant star.  To make the
>statistics workable they have put together a 64 million (!!!) pixel
>CCD which will be mounted on an otherwise little used 50-odd inch
>worn-out telescope.  The CCD will then stare at the large Magellenic
>Cloud (LMC) to look for microlensing events.  They expect a
>jupiter-sized object to enhance a stares brightness for a day or two,
>a week or two for dwarfs, and possibly months for a black hole.
>
>The point, of this is that maybe the same detector will inadvertantly
>succeed in detecting planets.  It would be ironic if the first
>detection of a Jupiter-sized planet were in the LMC!

It is even possible they may discover a variable star. Some of these
are known in our own Galaxy.

Such an LMC patrol presents an interesting problem, one which may be
solved for them by the time they get their experiment on the air. The
data processing problem will be huge! There will have to be many
output spigots for a variety of interesting data. For example,
Henrietta Leavitt's Cepheids ought to be monitored and many more
added to those already cataloged. (At lower amplitudes - Cepheids can
be quite subtle. Polaris, for example, is thought to be a Cepheid.)
If the data acquisition and analysis problems can be overcome then
this project should be a goldmine, at least from the point of view of
the observer who feels that weekly publication is a good thing.

If I had a machine like that I'd point it into the center of the Galaxy.

Leigh

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

Date: 26 May 1993 22:12:36 GMT
From: [e-mail]
Subject: Detecting planets in other system
Newsgroups: sci.space,sci.astro

The MACHO microlensing is an amibituous undertaking to detect small
statistical fluctuations in the brightnesses of background stars due
to a foreground population of gravitating objects.  The statistical
signature strongly depends upon the mass and distribution of the
foreground objects.  The background field is chosen to be the Large
Magellanic Cloud because that has the highest density of stars per
square arcminute.  The detector system works quite well and much of the
data acquisition flows through a 50 Mhz PC.  There are several technical
problems involving intrinsically variable stars, nightly seeing variations,
and optimal pixel sampling, but nonetheless, the experiment is working
and results are coming in.  I don't think anyone in the group is prepared
to make a positive statement regarding microlensing but in another 2 or
3 years there will be enough data to show it or rule it out - so in that
sense it is quite a good experiment.

In another sense, however, its even better because it represents the first
MOSAIC CCD system that actually works and furthermore shows that 64
million pixels per readout can still be handled effectively by existing
workstations.  Someday, we hope, several such cameras will be routinely
monitoring the sky at a variety of wavelengths.

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

Date: 26 May 93 21:56:00 GMT
From: Pat <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|In <1ttm8j$[e-mail]> [e-mail] (Pat) writes:
|
|>|[e-mail] (Pat) writes:
|>|>Ken seems fixated on this measure of performance.
|>|>I would suggest that we not look at mass returned,  but Useful
|>|>Cargo Returned.
|>|>In that Case we have,  1 LDEF,  4-5 SpaceLab flights,  and probably
|>|>appx 100 GAS Cans.
|>>>Not a lot for 12 years of missions.  The soviets probably have
|>>>returned as much using capsula  vehicles and with soyuz.
|
|
|>Nobody gunned down my thumb sketch.
|
>Well then, a small caliber bullet:  I don't know that I'd include the
>SpaceLab as 'cargo' -- it's just another matter of having to haul
>facilities up and down that would be better if we could simply leave
>the same facilities on orbit.

I included the SpaceLabs as returned mass because they were
intended to return in whole  and be re-fitted for additional
flights.   I could have been more detailed and merely counted as
mass the Spacelab  Locker units,  but I thought I'd give Ken
thhe benefit of the doubt.  I really could have subtracted most of
the weight of LDEF.  given LDEF has never flown again and never
will,  it's frame weight is essentially ir-relevant as a performance
measure.  I had heard though that the LDEF frame itself was extensively
studied, due to it's over long stay,  hence I decided to call all of
LDEF  useful mass returned.

If i wanted to be very narrow in my estimate i could have said
128? LDEF trays,  50 Some  SPaceLab  Racks,  and appx 100 GAS Cans.

No matter what, it's ascathing condemnation of the SHuttles mass return
capacity.

pat

    Actually, here is a real condemnation of SHuttle.  If shuttle
is so great,  why did the soviets Abandon BURAN?  Buran  is 99% like
shuttle in capacity,  except BIG PLUS, it has Liquid Boosters,
and a jet engine assist on landing.  Massive safety plus over STS.
Yet the Soviets abandoned BURAN totally, once they saw how operationally
inefficient it would be,  and with the observation of how STS is strangling
our space program.

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

Date: Wed, 26 May 1993 21:09:09 GMT
From: James Davis Nicoll <[e-mail]>
Subject: Moon Base
Newsgroups: sci.space

    I think Mr. Coffman may have forgotten one cost of long
transit times. *Someone* will have money tied up for the duration
of delivery. That money had better pay back at better than bank
interest rates would or the investors are potentially  losing
money. That is going to effect pricing. A naive calculation
indicates that if the bank rate is 5%, and the cargo takes
14 months to arrive (from the asteroid belt), then the banks
would have paid about $1.06 for every dollar tied up in the
cargo for that time. If someone else can deliver the same
product in less time, that aspect of costs will be less.

    Also, turning *off* the pipeline (In the event that
the market for the product crashes, for example) takes time.
If product x is arriving every week in the 14 month example,
that means there are 56 cargos of product x that *will* arrive,
after production stops. There's a certain inflexibility to
'Leinster-style' pipe-lines, which may worry investors.

                        James Nicoll



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

Date: 26 May 1993 17:44:30 -0400
From: Pat <[e-mail]>
Subject: Moon Base
Newsgroups: sci.space

Comments on long duration materials delivery from space.

Interest rates are routinely calculated for long lead time
capital equipment such as New aircraft.  those have up to a 10
year lead from design to delivery,  and people are making orders
based upon palns 5 years out.  I think it's do-able.

AS for price fluctuation,  then  you will see a futures market
in asteroid volatiles.   Look at wheat.  you have a  4-8 month
pipeline from the time crops are planned to delivery.

All parties involved sell/buy futures contracts to reduce risk.

Crop failure,  excess rain,  Hail, storms,  Bumper soviet harvests,

being a farmer can sometimes be like riding a roller coaster.

pat

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

Date: 26 May 1993 20:36:08 GMT
From: Andy Carol <[e-mail]>
Subject: NASA CD-ROM add/price
Newsgroups: sci.space

Does anyone have the price list and where to write for the NASA
CD-ROMs which are available?  I'm looking for the Voyager and
Viking CD-ROMs which I've heard about.

I also understand the Voyager CD-ROMs are compressed, does anyone
know what method was used?  Is it lossy or lossless?

I've already looked in the FAQ without luck.

--- Thanks!

Andrew Carol           [e-mail]

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

Date: Wed, 26 May 93 21:22:54 BSC
From: [e-mail] (Francisco da Fonseca Rodrigues)
Subject: Planets around other stars

    I read an article about the discovery of dust around Vega. Other
stars show dust around them: Beta Pictoris, Fomalhaut and Epsilon Eridani
are examples.

    In reference to Epsilon Eridani, a few years ago I read an article
in a local newspaper, saying that a canadian team of astronomers had used
interferometry to seek planets around near stars, and that 16 candidate
stars showed some signs. Epsilon Eridani and Gama Cephei were the more
promising stars. But after this, I heard no more about this research.

    I remember that an article was submitted to Astronomy Magazine,
and published. I think the year was 1987 or 1988. Does someone have any
information about other results or even confirmation of those observations?

    Other star I read that could have planets (or a brown dwarf) is 70
Ophiuchi, a binary star 17 light-years from Sol. But I also read that this
possibility was rulled out after new researches.

    If someone have other information about this, please send them.

    Thank you very much,

    Francisco.

-----------------------=====================================----the stars,----
|    ._,               | Francisco da Fonseca Rodrigues    |       o   o     |
|  ,_| |._/\           |                                   |     o         o |
|  |       |o/^^~-._   | COTUCA-Colegio Tecnico da UNICAMP |   o             |
|/-'    BRASIL      | ~|                                   |  o      o o     |
|\__/|_            /'  | Depto de Processamento de Dados   |  o    o  o  o   |
|      \__  Cps   | .  |                                   |   o  o  o    o  |
|        |   * __/'    | InterNet : [e-mail] |     o o      o  |
|        >   /'        | BitNet   : cotucamp@brcfetmg      |             o   |
|      /'   /'         | Fone/Fax : [phone]        | o         o     |
|     ~~^\/'           | Campinas - SP - Brasil            |    o   o        |
-----------------------=====================================----like dust.----

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

Date: 26 May 1993 18:07:51 -0400
From: Pat <[e-mail]>
Subject: The crew is toast
Newsgroups: sci.space

THe F-111,  and the B-1A?  had a crew ejection capsule that was
designed for such a similiar escape.  THe problem is, at least on STS,
a probable ejection occurs over water,  thus the crew compartment
must have a bouyant capcity.  A tough problem for a supersonic
break up.  No good,  surviving the water impact to drown as the
compartment floods,  as it may have done during 51-L.

What they really needed were ejection seats.  According to henry,
Martin baker had a design for seats for all STS occupants.

Of course, that would require Nasa spending money on safety improvements as opposed
to shuttle ops.  My opinion, here.

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

Date: Wed, 26 May 1993 21:42:50 GMT
From: Robert Tilden <[e-mail]>
Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction?
Newsgroups: sci.space,sci.space.shuttle,rec.arts.books

I think Tom Wolfe painted a fairly accurate picture of the early part of the
US space program. His book certainly captures the emotions of the times better
than any other book I've run across.

I grew up on the east coast of Florida, quite near the Cape, and remember
many of the details Wolfe mentions in his book. I could watch the launches
from my back yard, bright balls of fire rising up and out over the Atlantic,
the rocket itself not visible without binoculars. If a manned launch occured
during school hours the school would often hold a fire drill so we could
watch. It took a minute or so for the low rumble of sound to get to us-
usually (as I remember) just as the rocket's first stage was jettisoned and
it disappeared from sight.

I remember riding my bike to Patrick AFB to watch the homecoming 'parades'
for the Mercury astronauts. They were usually hot, dusty, glaring affairs
with people lined up on either side of A1A and a small motorcade of
convertibles moving by at a leisurely pace. Didn't seem very heroic at the
time.

_The Right Stuff_ brought back a lot of memories of the times, and Wolfe
was pretty accurate about the events I'm familiar with...

-Bob Tilden    [e-mail]



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

Date: Wed, 26 May 1993 22:10:36 GMT
From: Roger Noe <[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] (Ron Baalke) writes:
>... my best guess for the upper limit
>of the heliopause currently is about 90 to 120 astronomical units
>(AU) from the sun," said Dr. Ralph McNutt, ...
>     Voyager 1 currently is at 52 AU (4.9 billion miles or 7.8
>billion kilometers from the sun), and Voyager 2 is at 40 AU (3.7
>billion miles or 6 billion kilometers) from the sun.

In what range of time are Voyager 1 and 2 expected to actually reach
the heliopause?  Will there be a pronounced discontinuity, where it
can be said objectively that the satellites have "reached the
heliopause", or is this more of a continuum and a subjective
determination of where the heliopause begins?

Didn't something similar happen when each of our interplanetary
satellites reached Earth's magnetopause?  Isn't there at least a
qualitative similarity between these two "boundaries"?

OK, I'm done asking questions for today. :-)  Thanks in advance
to anyone who endeavors to produce serious answers.
--
Roger Noe                           [e-mail]
Department of Computer Science      40:06:39 N.  88:13:41 W.
University of Illinois              [phone]
Urbana, IL  61801  USA

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

End of Space Digest Volume 16 : Issue 635
------------------------------