Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_5/V15NO529.ZIP/V15NO529

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Date: Thu, 10 Dec 92 05:10:49
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #529
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 10 Dec 92       Volume 15 : Issue 529

Today's Topics:
                      DC vs Shuttle capabilities
                           DoD launcher use
       Earth flyby comments (was Re: Galileo Update - 12/08/92)
                            heat exchange
                   live video of the lunar eclipse
                      Magellan Update - 12/04/92
                         NSSDC Data on CD-ROM
                           Orbit Question?
                        Pop in space (2 msgs)
                         Scuttle replacement
                Space Based Data Compression Standard
                 STS-48 and "SDI": Oberg vs. Hoagland
           Terminal Velocity of DCX? (was Re: Shuttle ...)

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

Date: 9 Dec 92 21:44:57 GMT
From: Henry Spencer <[e-mail]>
Subject: DC vs Shuttle capabilities
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>... A more intelligently designed
>spacecraft is badly needed to replace Shuttle, but the DC program
>isn't it. It may be *part* of a fleet of specialized vehicles that
>replace Shuttle, but it can't do many of the things that Shuttle
>is capable of doing, lifting large payloads, carrying large crews,
>support Canadarm, return large objects, etc...

None of these things is really a fundamental problem.

Large payloads can go up in pieces for in-orbit assembly.  In fact, if
you believe Fairchild's old Leasecraft study, this approach is superior,
because plugging things together in orbit is easier than making absolutely
sure they won't come unplugged during ascent.  Remember that NASA was quite
happy, in the beginning, with a much smaller shuttle design.

DC-1's cargo bay will easily hold more crew than the shuttle can carry.
DC-1 is not going to replace Shuttle+Spacelab -- it's too small and its
stay time in orbit is too short -- but it could easily service a space
station that would.  Hauling Spacelab up and down all the time is
incredibly wasteful.

The Canadarm is nice, but I'm sure Spar would be delighted to supply a
cut-down version to fit on DC-1.

There appears to be no significant requirement to return large payloads.
I can't think of anything larger than a Spacelab experiment rack that
has to come down in one piece.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Dec 92 17:47:10 GMT
From: Henry Spencer <[e-mail]>
Subject: DoD launcher use
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>On a related note, I assume space will still be a valuable part of the
>DoD's strategy, so what will they be using from now on, if not the
>shuttle?  Titans and/or Deltas?

Titan IV is the USAF's pride and joy; they'll mostly use it, although the
expected launch rate has declined a bit with the demise of the USSR.
Smaller stuff will go up on commercial contract:  Atlas, Delta, Pegasus, etc.
And I would expect that there will still be occasional military experiments
on the shuttle, even if this is their last dedicated flight.

The military would like to see a government-run Atlas/Delta class booster,
which is one reason they've been consistently pushing ALS/NLS/etc -- they
want to control their own launcher programs rather than buying launch
services from contractors.  (That's one reason why Titan IV is so big
with them -- they never liked having to deal with NASA for the shuttle.)
Reagan (and Bush in his wake) supported free enterprise and kept the
wanna-be socialists more or less under control; I don't know whether the
Democrats will do likewise.

>Would the DC-1 be a potential market
>for the military, or is the market not even a concern, as much as
>gettting it to work, at this point?

The immediate concern is making DC-X work and getting DC-Y funded.  But
the military would most assuredly be interested in easier and cheaper
access to space.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Dec 92 10:46:39 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Earth flyby comments (was Re: Galileo Update - 12/08/92)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, [e-mail] (Ron Baalke) writes:
> [Below I've summarized some of the highlights of Galileo's 1992 Earth-Moon
>  encounter.
>           Ron Baalke
> ]

Thanks, Ron.  Fascinating stuff.  Galileo is lost in the TV news these
days thanks to overwhelming coverage of the Somalian affair, so I
haven't yet seen any images.  Fortunately my Satellite Dish Buddy made
me a tape of the press briefings and I'll get to see it soon.
Comments follow.

>    Dec 7  - Moon observations.  Galileo will be passing three times closer
>             to the Moon than it did in its first Earth flyby two years ago.
>             It passed over the North Pole of the Moon at a distance of
>             110,288 km (68,530 miles).  Observations include multi-spectral
>             coverage and mapping of the Moon, and searching for indications
>             of water at the North Pole.

Igloos? Icebergs? Eight tiny reindeer?  Actually, the Near-Infrared
Mapping Spectrometer was looking for evidence of hydrated minerals
which might be left from comet collisions.  A couple of years ago, one
guy on the project was speculating they might be able to see shadowed
ice patches (if there *are* any) by starlight but I haven't heard what
came of the suggestion.

>             Obtain multispectral SSI images of the Andes mountain range
>             shortly after closest approach.  This area has been extensively
>             studied by Earth satellites which provides excellent "ground
>             truth" comparisons for the Galileo instruments.

This is a funny definition of "ground truth."  But I presume the area
has been studied by people on the GROUND too.

>
>             Acquire SSI coverage of as much as possible of the land area
>             of the Earth.  This will go on for 48 hours and the images will
>             be assembed to form a time-lapse zoom movie of the receding
>             Earth.

Ever seen the bumper sticker "Happiness is the planet Earth in your
rear-view mirror?"

>
>    Dec 9 -  GOPEX, an experiment to demonstrate the capability of a
>             deep space probe to receive and distinguish laser signal from
>             Earth.  A laser will be pulsed at Galileo from the Table Mountain
>             Observatory near Los Angeles and from the Starfire Optical Range
>             in New Mexico, and the SSI camera will be shuttered while slewing
>             across the Earth resulting in a series of illuminated dots in

>             the image.

"Caution: Do not look into laser with remaining camera."

>    Dec 10 - Continue GOPEX experiment.
>             Observe Asteroid Toutatis 4179 using the EUV (Extreme
>             Ultraviolet Spectrometer) instrument.

This is probably the only optical instrument aboard Galileo which is
superior to ground-based observations.  Wonder what you can find out
with it?  I don't expect Toutatis has an atmosphere, lightning, or
aurorae... (Nitpicking:  it's properly "4179 Toutatis," not "Toutatis
4179.")  The photopolarimeter might be useful, too, but not superior
to HST measurements.

>
>             Obtain periodic 3-filter SSI coverage of the Earth and Moon during
>             conjunction period, to produce color time-lapse movie sequence.
>             These images will be taken over a 14 hour period.

Eric De Jonghe says the Moon will only be a few dozen pixels across,
and very dark compared to the Earth.  Nevertheless I'm looking forward
to seeing this.

>    SSI Image Summary:
>                               No. of Images
>    Moon (multi-spectral)          1067
>    Earth (multi-spectral)         3594
>    Conjunction Movie (3-color)     168
>    GOPEX (Green filter)            160
>    Navigation Images               102
>    Calibration Images             1722
>                                   -----
>                     Total         6813

Good thing they don't have to pay to get these developed at the
drugstore!

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: 9 Dec 1992 13:31:52 -0600
From: Woody Baker <[e-mail]>
Subject: heat exchange
Newsgroups: sci.space

    Hi:

    I don't subscribe to this newsgroup, so please send any replys to
[e-mail] via email.  Please no flames.  I know that out
in netland, someone exists who can help me with this query, but don't know
where, so this is going to several news-groups.

    I am looking for software (hopefully on a '86 class machine) that
can model the heat flow in the following situation (or some one who has
done research in this direction)

    I need to model the heat flow from several cylindrical heat
sources embedded in a block of various materials.  I am looking for heat
flow gradiants into the surrounding mass.  I am also looking for software
that will model airflow through passages in this mass, and predict the heat
transfer, depending on speed an volume.

    I am designing a wood-fired central heat source for my retreat up
in the east texas woods.  My basic idea (and it is not a new one) is to
build 3 wood burners out of old hot water tanks, and embed them in a solid
9 ft * 9 ft * 6 or 8 ft block of standard three-hole bulding bricks.  I
wish to experiment with the placement of the 3 heat sources, as well as the
arrangement of internal heat passages in the bricks.  The whole thing will
be enclosed in a concrete block enclosure, with access to the 3 burners
from the outside, and forced air input at the bottom (the cold air return
duct), and a connection from the top into the ductwork in the house.
Needless to say I want to create the most effecient structure possible for
heat storage, with the most uniform distribution of heat storage within the
structure.  I also want to try to predict the temprature of the air coming
out, so I can work out the amount of cold air bleed needed to keep the
air temprature coming into the  house sane. (and how fast to run the fan(s)
to control the heat absorbtion of the air)

    I wonder prhaps if some of the code used by NASA to analyze shuttle
tile will work.  If anyone knows of software that might help me with this,
or has/is doing(done) research along this line, please let me know.


Cheers
Woody Baker

--
Woody Baker Postscript consultant/Flint knapper  512-837-8317 (Austin, Tx)

"If you ain't bleedin' you ain't knappin'" ---> go ahead, ask me...

[e-mail]
[e-mail] (temporary) is forwareded to woody@knapper

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

Date: 9 Dec 92 17:14:16 EST
From: Lenard Diggins <[e-mail]>
Subject: live video of the lunar eclipse
Newsgroups: rec.video.satellite,sci.astro,sci.space

hi folks,
    i couldn't check to see if someone else had posted this, so
please forgive me if you've already read this.

    MCET is uplinking live video of the lunar eclipse right
now on SBS-6, Transponder 16 (KU)  Freq. 12.0925 GHz.  we will
continue to uplink until 20:00 (Eastern Standard Time).

Lenard

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

Date: Thu, 10 Dec 1992 01:14:08 GMT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 12/04/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                       MAGELLAN STATUS REPORT
                          December 4, 1992

1.  Magellan continues to operate normally, transmitting a carrier
plus 40 bps X-band signal which is precisely tracked by the DSN
(Deep Space Network) stations to provide gravity data.

2.  Yesterday the G2339 command sequence was successfully uplinked to
the  spacecraft and will begin execution this morning on orbit #6352.
This sequence is similar to the previous two-week control sequences,
but contains a radio science experiment to be performed on Sunday
night.

3.  Spacecraft temperatures remain in the expected range.  Bay 7,
which contains the CDS (Command Data Subsystem), is at 51 degrees C
with a cycle depth of 6 degrees.  Transmitter B is at 52.7 degrees C
which is below the temp where satisfactory performance at 1200 bps
is found.

4.  The spacecraft has completed 6240 orbits of Venus; 604 so far in
Cycle 4, which will end on May 25, 1993.  Cycle 4 is now one-third
complete.

5.  Doug Griffith, Project Manager, traveled to Nagoya, Japan, where
he presented a paper at the 1993 International Space Symposium.  He
will return to Southern California today, and will be back in the
office on Monday, Dec. 7th.

6.  The project received a letter from NASA Headquarters assuring
$3.0M for funding of additional processing and archiving of Magellan
science data.  In addition to FY93 investigator contracts, the funding
covers radar processing to correct dynamic range and geometric
distortions in Cycle 2 F-BIDRs, the production of 30 additional
compact disks containing mosaicked images, the development of a "tool
kit" for analysis of stereo images, and the completion of data product
deliveries to PDS (Planetary Data Systems) and NSSDC (National Space
Science Data Center).
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The 3 things that children
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/  |_|/       |_____|/                     | space, dinosaurs and ghosts.

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

Date: Wed, 9 Dec 1992 17:31:01 GMT
From: Hunter Scales <[e-mail]>
Subject: NSSDC Data on CD-ROM
Newsgroups: sci.space,alt.sci.planetary,alt.cd-rom

[e-mail] (Ron Baalke) writes:

>In article <[e-mail]>, [e-mail] (Kenneth Porter) writes...
>>> Yes.  Keep in mind the images are the raw unprocessed data from Voyager.
>>> The images are black and white.
>>
>>So where does the color come from that we see in the news? Is the
>>original data in color and the CD just omits it, or is the color
>>synthesized somehow?

>The images were taken with various color filters.  By combining images
>(normally 3 images) taken with different color filters, you get the
>color.

>>And does the retrieval software have all of the neat histogram stuff
>>that we saw as the images came in live? It would be cool to play with
>>false color on these images.

>IMDISP can display the histograms.  Also, it has 11 built-in color palettes,
>along with about 30 other color palettes that can be loaded in from files.
>The program also allows manipulation of the color palettes.

    Hmm, I was interested in this some time ago and I got to following
response:

+     But the individual images are still monochrome, right?  That's the
+  way they are stored on the CD-ROM, as the original data.  The Browser
+  program mentioned above now comes with another program called "True
+  Color!" that allows one to "register" the multiple filter images and
+  render a reasonably good true color image.  The multi-filter images
+  are not all at exactly the same alignment and each image has to be
+  adjusted and rotated slightly in order to get them all lined up.
+  JPL-quality images take some more extensive image processing than that
+  but the Mac program gives good results, nonetheless.
+
+ -- Lee E. Brotzman                    Internet:  [e-mail]
+  -- ST Systems Corp.                   SPAN:      NSSDCA::BROTZMAN
+  -- Astrophysics Data System           BITNET:    ZMLEB@SCFVM
+  -- National Space Science Data Center "Prayer: the last refuge of a scoundrel"


    So, does this "True Color" program exist, and can it
    assemble reasonable true color images?

--
Hunter Scales                                      Motorola Semiconductor Inc.
[e-mail]                      Austin, Texas
"The opinions expressed in this posting do no necessarily reflect
those of the management"

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

Date: 9 Dec 92 17:36:39 GMT
From: Henry Spencer <[e-mail]>
Subject: Orbit Question?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>What about using the solar array itself as the solar sail and have it so that
>it could be moved to control how it would move away from the Earth and side to
>side, etc...

Not impossible but not very practical either.  Solar arrays do not make good
solar sails (too heavy and not reflective enough), and a solar sail for this
mission is going to be enormous compared to any plausible solar array.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Wed, 9 Dec 1992 17:18:31 GMT
From: Frank Crary <[e-mail]>
Subject: Pop in space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Charles Stephens) writes:
>>> I don't know - didn't Coke or Pepsi device special cans for the Space
>>> Shuttle crew? :)

>>Yes, and you can see the Coke device in the Coca-Cola museum in
>>Atlanta, GA.  I know it's a tad far for you to go, but some of
>>our other readers might be nearby.

>    I've seen it, really high-tech.  I looks like one of those old portable PC's.
>It has a screen and some other really weird hardware.  Now I have faith that my tax
>dollars are really going to a good cause.

In which case, the one you saw was not the one tested on the Spacelab 2
mission. The Coke dispenser looked like a cross between a shaving cream
can and a thermos. The design was funded exclusivey by Coke. NASA agreed
to test it on orbit, and Coke thought the advertising justified the
R&D money. Pepsi heard about it, and talked NASA into also sending up
a Pepsi dispenser (something about government agencies not endorsing
a particualr product...) Pepsi put almost no money into R&D of their
dispenser, but (since almost no one remembers who won the taste test)
got about the same publicity as Coke. (The Pepsi dispenser essentially
_was_ a shaving cream can...) After tasting the Pepsi and drinking all
of the Coke, the crew proceeded to play all sorts of fun games with
fluids in zero gravity using the left-over Pepsi.

                                                   Frank Crary
                                                   CU Boulder

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

Date: 9 Dec 92 09:59:45 GMT
From: Matthew Thomas DeLuca <[e-mail]>
Subject: Pop in space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>In article <[e-mail]> [e-mail] (Charles Stephens) writes:

>>    I've seen it, really high-tech.  I looks like one of those old portable
>>PC's. It has a screen and some other really weird hardware.  Now I have faith
>>that my tax dollars are really going to a good cause.

>In which case, the one you saw was not the one tested on the Spacelab 2
>mission. The Coke dispenser looked like a cross between a shaving cream
>can and a thermos. The design was funded exclusivey by Coke.

What he saw (being an Atlanta resident, I've been there a few times) was a
zero-gravity soda-fountain.  Now that I think about it, though, I can't for the
life of me think of what kind of a container they dispense it into...

The Coke can, on the other hand, looks a lot like, well, a can of Coke.

Re: Pepsi.  As I recall, the problem with the zero-gravity Pepsi can was that
the designers forgot there was no gravity in orbit (duh...what was the point
of the exercise, then?) which caused the carbonating unit (it had an internal
carbonator) to fail; I believe you had to shake it to make it work, as
opposed to the reasonably functional Coke design.
--
Matthew Thomas DeLuca
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:      ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew
Internet: [e-mail]

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

Date: Wed, 9 Dec 1992 17:29:50 GMT
From: Henry Spencer <[e-mail]>
Subject: Scuttle replacement
Newsgroups: sci.space

In article <#4c2#[e-mail]> [e-mail] (Greg Moore) writes:
>>   Laser Launchers -- what little funding is being spent comes from
>>        LANL, and LLNL, both DoE labs, with a large component of
>>        SDIO funding.  Not NASA funded.
>
>    This may come as a big surprise to Leik Myrabo here at RPI...
>as I recall, NASA signs his checks.

Myrabo's designs, while interesting, hardly qualify as things that are
likely to fly in the next ten years.  (The ones I've seen, anyway.)
He's working on third- or fourth-generation laser-launcher techniques,
futuristic research with no immediate practical relevance.

What little was being spent on laser launchers that could actually be
built in the near term, things that might actually be useful soon, was
not NASA money.  (Past tense used advisedly -- last I heard, the current
funding for laser-launcher work is zero.)
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Dec 92 18:15:56 GMT
From: Nick Beser <[e-mail]>
Subject: Space Based Data Compression Standard
Newsgroups: comp.compression,comp.compression.research,sci.astro,sci.space

        New Standard Development - Call for Participation

             Standard for Space Based Data Compression

At the November 6, 1991  AIAA Standards Technical Council meeting a
three part project to develop a Space Based Data Compression Standard
was approved. This is a multi-year effort and will result in a Data
Compression Guide, an Evaluation Criteria/Reference Data Set and a draft
standard for space based data compression.

Why Data Compression?

Space Based Observations require the transmission of a variety of different
types of data through the spacecraft communications system to the ground.
The data must be sent though a communications system that is limited in
bandwidth and is being shared among sensors. Greater utilization of the
limited resources of an observation system can be accommodated by the use
of data compression. There is a perception that data compression is an
experimental technique and this is supported by the absence of ANSI or
ISO standards that guide the design and implementation of space based data
compression. Data compression has been used on board satellites since the
mid 1960's. The lack of standards coupled with the lack of historical
record and need to use data compression on future missions makes this
project both timely and urgent.

Call for Help:

The success of this project is dependent on recruiting an active committee
that will pull together the different disciplines that make up the data
compression problem. To complete this project we will be writing a data
compression recommended practices guide that will include background
theory, descriptions of techniques, case studies and other implementation
considerations. Data compression evaluation criteria and reference data
will also be developed that will include sensor and mission requirements as
well as system design information. We will be developing a method of
comparing and rating the performance of different data compression
methods, and identifying test data that is representative of space based
collected data. The test data and evaluation software will be published as a
CD-ROM so that projects and companies that want to evaluate their
compression methods can have a common framework for performance
measures. We currently have outlines of the recommended practices guide,
code for compression metrics, test images, and some draft material.
Depending on the outcome of the first two activities a data compression
standard will be either endorsed or developed.

We are looking for researchers and engineers who are engaged in the
development, evaluation and selection of data compression methods for
space applications. We are also looking for Sensor and Experiment Design
Experts and Systems Engineers to help write sections of the Guide
including case studies of past, current and future missions. If you have an
interest in the application of data compression to space based data or know
of someone at your company who is currently working the problem, please
join us at the next SBOS/COS or join our e-mail list. Our next two
meetings will be held in the Baltimore-Washington area.

We have established an Electronic Mail List to help keep the committee in
contact during this project. If you have DOD Internet access or internet
mail, our address to join the mailing list is:

    [e-mail]

The address to send messages to the committee is:

    [e-mail]

All messages sent to the space-comp-std address will be repeated to
everyone on the mailing list. Send your internet mail address to the space-
[e-mail] address to join. Using this forum,
we can keep everyone informed of progress, and get comments on drafts
on a daily (in some cases minute) basis. We also have an archive site
located at aplcomm.jhuapl.edu that is reachable using internet ftp (File
Transfer Protocol). We plan to use the archive site to store drafts,
evaluation software and small reference data sets.

Dr. Nicholas Beser (APL)            Dr. Thomas Lynch (Hughes)
[phone] ext 4476                    [phone]

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

Date: Wed, 9 Dec 1992 17:25:02 GMT
From: Henry Spencer <[e-mail]>
Subject: STS-48 and "SDI": Oberg vs. Hoagland
Newsgroups: sci.skeptic,sci.astro,sci.space,alt.alien.visitors

In article <[e-mail]> [e-mail] (Dean Adams) writes:
> >I am happy that Oberg's explanation fits with what is shown on the video.
> >The UFOs and the missile which shoots them down
>
>Oh, brother!  With examples like this how are people supposed to
>ever take *ANY* "sightings" reports at ALL seriously??

Ah, but an occasional example like this is very useful.

How, you ask?

Well, the first thing you learn in any decent course on how to do historical
research is that you never, never, never blindly take anybody's word for
anything, and you always, always, always cross-check your sources (if you
can...).  One very useful method of cross-checking is to see what your
source thinks of something that is well established as definitely fact or
definitely fiction.

If you ask a UFO enthusiast what he thinks of the STS-48 UFO, and he thinks
it's for real... then you know how much faith to put in sighting reports
from *him*.

Such a pity that George Adamski died; asking UFOlogists what they thought
of him was a marvellous test of whether they had their heads screwed on
securely.  (The amazing thing was how many of them treated this obvious nut
as a respected colleague, thus flunking the test...)  Maybe the STS-48 UFO
can be the new test case.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Dec 92 17:52:36 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>In <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>Mass ratio is a very good measure of margin, and DC-Y's will be very
>>very much pushing the envelope.
>
>If that's true, a supertanker must also push the edge of the envelope.
>But, of source, that's absurd.

SSTO masses 100 times it's payload while a supertanker's payload masses
100 times the vehicle mass. It does push the envelope in ship handling
and in sea handling. Supertankers would be impractical without satellite
weather observation and computerized control. They aren't just scaled
up tramp steamers. They are specialized, expensive, and delicate systems
that have to receive special handling to survive. The consequences of
a failure can be grim. Now why does that sound familiar?

Gary

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

End of Space Digest Volume 15 : Issue 529
------------------------------