Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO453.TXT

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Date: Wed, 25 Nov 92 05:00:10
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #453
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 25 Nov 92       Volume 15 : Issue 453

Today's Topics:
                     Camera Aspect -- What is it?
                               GE Astro
                        on the lighter side...
            on the lighter side...   SDIO's SSTO (lyrics)
                       Pumpless Liquid Rocket?
      Russian Photon capsule lands in Pacific & comes to Seattle
                          Scientific method
                      Shuttle Computer Problems
                     Shuttle replacement (9 msgs)

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

Date: 24 Nov 92 13:49:50 GMT
From: Charles Fletcher <[e-mail]>
Subject: Camera Aspect -- What is it?
Newsgroups: sci.space

The title says it all--Could someone give me a definition of "Camera Aspect"
as it relates to satellite navigation. Any references would also be helpful.

Thanks in advance,

Charlie




--
    NeXTMail to:        |    ...to confer, converse, and
    [e-mail]    |    otherwise hobnob with my
                |    brother wizards.

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

Date: 24 Nov 92 15:51:30 GMT
From: Bob McGwier <growler!n4hy>
Subject: GE Astro
Newsgroups: sci.space

GE Astro was sold, lock, stock, and barrel to Martin-Marietta for three
billion $ (not all cash, stock, etc.).  I live about a 1.5 km from GE
Astro and my friends are breathing a big sigh of relief.  There have been
layoffs there that have made the division MORE profitable (it already was)
and they have a backlog of business.

Bob McGwier

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

Date: 24 Nov 92 11:18:25 GMT
From: "P. Douglas Reeder" <[e-mail]>
Subject: on the lighter side...
Newsgroups: sci.space

SDIO's SSTO
to the tune of "Old MacDonald"
lyrics by Doug Reeder
from a suggesstion by someone I don't remember and would like to thank

These lyrics are hereby released to the public domain.


first verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were some engines
e-i-e-i-o
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o

second verse:

SDIO's SSTO
e-i-e-i-o
On that ship were some cryogenic fuel tanks
e-i-e-i-o
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


third verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were more fuel tanks
e-i-e-i-o
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


fourth verse:

SDIO's SSTO
e-i-e-i-o
On that ship were still more fuel tanks
e-i-e-i-o
with a gulp-gulp here, and a gulp-gulp there,
here a gulp, there a gulp, everywhere a gulp-gulp
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


fifth verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were some astronauts
e-i-e-i-o
with a whoop-whoop here, and a whoop-whoop there,
here a whoop, there a whoop, everywhere a whoop-whoop
with a gulp-gulp here, and a gulp-gulp there,
here a gulp, there a gulp, everywhere a gulp-gulp
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


Ad Nauseum, Ad Astra!

--
Doug Reeder                              Internet: [e-mail]
Div, Grad & Curl                         USENET:   ...!tektronix!reed!reeder
programming & derivative work            BITNET:   [e-mail]
I am actively seeking scientific programming contracts.

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

Date: 24 Nov 92 11:24:57 GMT
From: "P. Douglas Reeder" <[e-mail]>
Subject: on the lighter side...   SDIO's SSTO (lyrics)
Newsgroups: sci.space

SDIO's SSTO
to the tune of "Old MacDonald's Farm"
lyrics by Doug Reeder
from a suggesstion by someone I don't remember and would like to thank

These lyrics are hereby released to the public domain.


first verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were some engines
e-i-e-i-o
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o

second verse:

SDIO's SSTO
e-i-e-i-o
On that ship were some cryogenic fuel tanks
e-i-e-i-o
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


third verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were more fuel tanks
e-i-e-i-o
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


fourth verse:

SDIO's SSTO
e-i-e-i-o
On that ship were still more fuel tanks
e-i-e-i-o
with a gulp-gulp here, and a gulp-gulp there,
here a gulp, there a gulp, everywhere a gulp-gulp
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


fifth verse:

SDIO's SSTO
e-i-e-i-o
On that ship there were some astronauts
e-i-e-i-o
with a whoop-whoop here, and a whoop-whoop there,
here a whoop, there a whoop, everywhere a whoop-whoop
with a gulp-gulp here, and a gulp-gulp there,
here a gulp, there a gulp, everywhere a gulp-gulp
with a blub-blub here, and a blub-blub there,
here a blub, there a blub, everywhere a blub-blub
with a brr-brr here, and a brr-brr there,
here a brr, there a brr, everywhere a brr-brr
with a roar-roar here, and a roar-roar there,
here a roar, there a roar, everywhere a roar-roar
SDIO's SSTO
e-i-e-i-o


Ad Nauseum, Ad Astra!

--
Doug Reeder                              Internet: [e-mail]
Div, Grad & Curl                         USENET:   ...!tektronix!reed!reeder
programming & derivative work            BITNET:   [e-mail]
I am actively seeking scientific programming contracts.

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

Date: 24 Nov 92 15:21:32 GMT
From: David Toland <[e-mail]>
Subject: Pumpless Liquid Rocket?
Newsgroups: sci.space

In article <schlegel.722562761@cwis> [e-mail] (Mark Schlegel) writes:
>[e-mail] (Henry Spencer) writes:
>
>>The hydrostatic head in the plumbing, while useful -- it figures into the
>>design calculations for both pump-fed and pressure-fed rockets -- is not
>>enough to run a pressure-fed engine particularly well.  Even low-performance
>>pressure-fed engines need 5-10 atmospheres of pressure.  (One atmosphere is
>>a 10m column of water, and most fuels and oxidizers are substantially less
>>dense than water.)
>
I'm surprised no one has posted what occurred to me (and I replied to
the original author via email).  The reaction chamber has a pressure
that's approximately equal to the thrust of the engine divided by the
area of the nozzle orifice (actually a bit higher due to turbulence
losses in the nozzle), so you have this chamber pressure working against
the hydrostatic pressure.  I haven't set up a mathematical model of
this, but I find it hard to believe that a practical rocket motor
could be built with a high enough hydrostatic pressure to feed the
reaction chamber.
--
--------------------------------------------------------------------------
All opinions are MINE MINE MINE, and not necessarily anyone else's.
[e-mail]   |  "Laddie, you'll be needin' something to wash
                           |  that doon with."

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

Date: Tue, 24 Nov 1992 09:14:59 -0800
From: Glenn Chapman <[e-mail]>
Subject: Russian Photon capsule lands in Pacific & comes to Seattle

     Radio Moscow on Nov. 22 announced the successful splashdown of the
Europe-American 500 sample capsule, which was launched on Nov. 16th (see Nov.
16th posting for launch details).  This was a 5 day special flight of the
Photon space processing style sample return probe.  In this case the capsule
is filled with items to send "good will messages" in celebration the voyage
of Columbus.  The capsule with landed about 300 Km (190 mi) off the
Washington state Pacific coast and was recovered by a Russian satellite
tracking ship.  The ship will be docking in the Seattle area today (Nov. 24)
and apparently will be open for visitors. A Tacomo TV stationed showed news
clips this morning of the Photon capsule being lifted out of the sea onto the
ship.  Photon is a spherical capsule which is derived from the first Vostok
capsules, not the more modern Soyuz bell shaped return system.  The capsule
will be on display in Seattle.
     In other activity on board the Commonwealth of Independent States Mir
space station cosmonauts Anatoli Solovyov and Sergei Avdeyev Anatoli
Artsebarski and Sergei Krikalev (up for 120 days now) ejected a small
satellite from the air lock on Nov. 23.  Meanwhile the CIS has been holding
discussions with the European Space Agency concerning cooperative space
programs.  According to a Radio Moscow report agreement has been reached
which will see 3 ESA cosmonauts visit the Mir space station in the next few
years.  Also $50 million in contracts will go to Russian space companies.

                                                        Glenn Chapman
                                                        School Eng. Science
                                                        Simon Fraser U.
                                                        Burnaby, B.C., Canada

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

Date: Tue, 24 Nov 1992 15:54:46 GMT
From: Herman Rubin <[e-mail]>
Subject: Scientific method
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (John Roberts) writes:


>-In article <[e-mail]> [e-mail] (John Roberts) writes:
>->... for instance, for instance, the Earth-impact model of the formation
>->of the moon has risen from obscurity to the "most favored model", with
>->(as far as I know) little or no new input of information - it's based on
>->mathematical models and old Apollo and Voyager data...

>-There is no problem testing a new theory quite rigorously using old data,
>-if you do it carefully.  The trick is simply to get some testable predictions
>-out of the theory before you look (closely) at the data, and then see if it
>-checks.  This does get more difficult if the new theory has to be calibrated
>-using the same data, but sometimes it can still be done.  It is more
>-satisfying to have prediction precede experiment, because that *guarantees*
>-that the theory was not custom-cooked to match the results,

>I agree it can be done, but there are some potential difficulties that
>investigators have to watch out for. Most obvious is "cheating" - theorists
>making use of information that they pretend not to have when constructing
>their models. To prevent that, somebody might get the idea of keeping
>significant portions of the observational data "secret" - to be released
>only after theories have been formulated. This of course would inhibit
>the distribution of information (slowing the development of better theories),

            ...............

From a purely decision theoretic standpoint, what one ideally should do is to
have a weight (probability) assigned to every model, and even more so, a
measure (probability) on the model + parameter-value space.  There are two
problems with this; first, it is too large for the universe to contain the
representation, and second, it would be too difficult to use.

What is needed (NOT what is usually done now) is to recognize that the models
accepted are accepted for the accuracy of their approximation.  This problem
is sometimes formally tractable.  But it is unlikely that any model in use is
correct.  The question is whether the inaccuracy of the model outweighs the
predictability due to its simplicity.

Considering that there are an infinite number of possible models, generally
looking at the data hard enough will find a "reasonable" one which fits.
This is not always true; the behavior of an imperfect gas was not well
modeled by looking at data, rather by the use of theory.  Improving on
the van der Waals model was done by using more involved theory, not by
looking at the data and improving the fit.


--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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

Date: 24 Nov 92 05:49:00 GMT
From: [e-mail]
Subject: Shuttle Computer Problems
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes...
>
>Monday November 23 10:20 EST
>
>I'm looking for some help out here in the net. Any physists or experts
>in electron physics out there?
>   The problem we're having is with both the General Purpose Computers
>(GPCs) onboard the shuttle as well as the Main Engine Controllers (SSMEC).
>Both experience single bit upsets while in orbit. The GPCs have one bit
>error correction and log these upsets in what we call a soft error counter.
>For the SSMEC, it has no error correction. We dump the SSMEC memory after
>landing and determine how many upsets have occurred. Well today when the
>SSMECs were powered up on Discoveries three Main Engines, the standby
>computer on engine 3 had one bit flipped from the last time it was powered
>up (about a week ago). The GPCs have also experienced soft errors while at
>the pad. The current theory is that high energy particles striking the
>memory cell impart energy which changes the state. My question is if
>high energy particles can change the memory on the shuttle sitting on the
>pad. Why aren't all the other computers in the world inflicted with the
>same problem? Has anyone heard any studies being done on this?
>

No Studies that I can site, but I worked in R&D for a formerly leading
microcomputer manufacturer in the 80's (Vector Graphic) and we concluded
in the lab that at least some of the processor random lockups that were
experienced by our systems were the result of cosmic ray strikes at ground
level. The reason you never hear about it in the commercial world is that
no one uses error detection and correction. It is too expensive for a
cheap microcomputer that you can just reboot to solve the problem. A potential
solution (or at least a study you can do) is to build up a simple computer
with EDAC static or dynamic ram. Let it run for several months and log the
errors that the EDAC controller saves. EDAC chips from IDT enable you to do
this. You might want to use the same type of chips you use for the shuttle
system as this would be the most realistic simulation.

To make it more representative, use different shielding techniques as well as
no shielding and compare the results. As we go toward Solar minimum we will
have a far greater incidence of galactic cosmic rays penetrating to the inner
solar system, which will drive up the SEU and latch up rate in orbit. It is
relatively easy to deal with solar radiation flux. It is really a bear to
deal with cosmic rays. The techniques you use to combat solar fluxes actually
ENHANCE the problem relative to cosmic rays. This is due to the fact that
cosmic ray strikes on your shielding create a shower of secondary particles that
are in the right energy range to muck up your ram.

>Some info, the SSMEC uses 8K static RAM chips to make up the 64K by 16 bit
>main memory. When power is removed the memory is held up by a 3.56V
>battery. Todate it is believed that all bit flips have occurred at this
>lower battery voltage (power up voltage is 5V). This of course can not
>be proved (could have happened at full power in memory that was not being
>accessed).
>

In some fields (remote communications for example) computers use a watchdog
timer to auto restart the computer in the event of what is called a random
lockup failure. I designed some statistical multiplexers and did some
research on the voltage levels for the battery back up ram. What I found is
that you can turn the voltage down to BELOW the threshold for the generation
of a logic 1 (2.4 VDC) and still the memory will retain the information you
gave it. It will read as failed however due to the fact that the chip does
not have the ability to drive the outputs to a TTL 1. After restoring power
to the higher voltage level (above 2.4 VDC) the chips retained the information
and was able to read it out. Believe me I was surprised but after repeating the
test several times I became a believer. You might try this with a breadboard
of a simple system.


>Thanks.
>
>---------------------------------------------------------------------------
>Bob Waterman [Aqua]
>[e-mail]
>---------------------------------------------------------------------------
>

I hope this helps and I posted this to the general net in case others are
working around the same problem. We here are currently building a 16 bit
1 meg ram with full EDAC single bit correction, double bit detection of errors.
This will be the flight computer for our SEDSAT 1 satellite.

Dennis, University of Alabama in Huntsville.

PS Craig Lindley from Australia, If you still read this list please E-mail me.,
I lost your address when my address changed.

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

Date: 24 Nov 92 06:27:45 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>>Allen...
>
>>There is still *one* thing that the Space Shuttle can do that no other
>>launch system is capable of... bringing things back from orbit.
>
>At the moment there is no requirement for this capability. There simply
>isn't anything we can return. The only things brought back have been LDEF
>and a coupld of satellites. LDEF can be split up into several experiments
>(which would allow greater access) and fly every Soyuz mission.

Spacelab and Astro are two payloads that we want very much to return
from orbit on a regular basis. That allows them to be easily refitted
with new experiment racks and reflown. *That's* more cost effective
than throwing them away each time or refitting them in space. Neither
spam in a can nor a space station can handle the needs of those missions
as effectively or as cheaply as Shuttle. Not that they are all that
cheap mind you, but the experimental community thinks them worthwhile.

>Satellites cannot be brought back in a cost effective manner. The only
>ones brought back had to recive hundreds of millions is subsidies from
>us taxpayers.

Deadheading is never cost effective. But that's a management problem,
not a Shuttle problem per se. If you have to charge an entire Shuttle
mission against a satellite return, then it is expensive, but if the
return mission is piggybacked on a mission that carries things *to*
orbit, or does other experimental work, then landing *empty* is also
wasteful. Might as well bring down a satellite or two at the marginal
cost of a little maneuvering fuel. It's only useful for LEO satellites
due to the lack of direct to GEO capability of the Shuttle, which is
a shame, but it is a viable approach for those cases where Shuttle
will be going to those orbital altitudes anyway. The problem is that
NASA, actually a Presidential directive, has taken Shuttle out of the
trucking business before two way hauls were ever fully started.

>>The Shuttle, as you continually point out, is enormously expensive to
>>operate and inefficient when it is operating. But I don't think putting
>>a Soyuz on an Atlas (which *doesn't* have the lift capacity, BTW) or a
>
>Atlas is close. If it can't, we can go with Titan III for far far less.

Splash.

>>Titan IV (which isn't much better than Shuttle) is a reasonable solution.
>
>A Titan IV launch costs about a third of what a Shuttle flight costs.

Boom.

>>Shuttle certainly does not have 'twice the lift capacity' of Titan IV as
>>an earlier poster contended, but it does have about one-third more, I
>>believe.
>
>The new Titan SRMs will close most if not all of that gap.

Boom, boom.

>>Someday, we might actually
>>have a payload requiring all that lift, or return capacity, and as we did
>>after the demise of Saturn V, we'll be saying "why did we abandon it?"
>
>We wo't have those payloads as long as Shuttle is consuming a third of
>the NASA budget. It is a millstone holding us all to the Earth.
>
>There are plenty of heavy lift options we can go with when we need them.
>All are far cheaper than Shuttle.

That's the excuse used to abandon Saturn, Shuttle was supposed to be
far cheaper. Classic mistake to abandon working hardware until flight
proven replacements for the capabilities are in place. No more paper
spaceships please.

>On a related topic (your informative background on Delta Clipper) this
>>sounds like an excellent idea, but I'm nervous about it. Having grown up
>>in the Cape Canaveral area, and seen my share of boosters blow up or go
>>tumbling into the Atlantic,
>
>In the last ten years or so almost all the boosters have been blown up
>by range safety.

Small confort to a crewed vehicle. Boom is boom.

>>the idea of a powered descent and vertical
>>landing gives me the willies...
>
>Much safer than airplanes for most people. A DC crash will only affect the
>Spaceport. When aircraft crash they tend to kill people on the ground.

And a Shuttle crash landing is that of a glider, no boom, and perhaps
survivable by the crew. Plus who says the SSTO will crash on the Spaceport
grounds, few aircraft do. If they have a guidance failure, it might be
downtown Disney World. All those kids, consumed in flaming rocket fuel,
I can see the headlines now.

Gary

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

Date: 24 Nov 92 06:29:44 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>>the idea of a powered descent and vertical
>>>landing gives me the willies...
>>
>>Much safer than airplanes for most people. A DC crash will only affect the
>>Spaceport. When aircraft crash they tend to kill people on the ground.
>
>And as any Harrier pilot will tell you, a vertical powered landing is
>safer than a horizontal powered landing.  And either one is *much* safer
>than a Shuttle-style horizontal landing *without* power.

As any glider pilot will tell you, gliders don't burn on impact. Nor
do they pinwheel across the sky when a thrust diverter fails.

Gary

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

Date: 24 Nov 92 06:45:28 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>
>What I would do is to use the Titan to launch it, dock with any of the
>simple, easially built space station ideas exising today and operate it
>year round. That way we can use Spacelab 365 days a year instead of
>a week or so every two years.

It's awfully hard to dock with an idea. Real hardware may not work as
well as a paper spaceship, but it has the advantage of being real and
tangible.

Gary

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

Date: Tue, 24 Nov 1992 12:56:26 GMT
From: Dan Vento <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Allen W. Sherzer)
wrote:
>
> In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
> >Allen...
>
> >There is still *one* thing that the Space Shuttle can do that no other
> >launch system is capable of... bringing things back from orbit.
>
> At the moment there is no requirement for this capability. There simply
> isn't anything we can return. The only things brought back have been LDEF
> and a coupld of satellites. LDEF can be split up into several experiments
> (which would allow greater access) and fly every Soyuz mission.
>

Whoa, wait a minute! What about the dozens (probably hundreds, I haven't
counted) of microgravity, space science, DoD, and astronomy payloads that
have flown and been returned. This is a capability that the Shuttle has
that no other launch system can even come close to matching.

Dan Vento
[e-mail]

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

Date: 24 Nov 92 05:20:00 GMT
From: [e-mail]
Subject: Shuttle Replacement
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
>In article <[e-mail]> [e-mail] (Karl Dishaw) writes:
>>Has the shuttle ever lifted more than 20 tons (vs. the rated capacity
>>of 30 tons)? ...
>
>That "rated capacity" is obsolete; the shuttle has never been capable of
>lifting that much without violating one operating rule or another.

 (Yes,
>this means that the original specs were never met.)

No this means that after the development was nearly complete NASA added abort
modes to the launch phase that put severe strains on the orbiter frame. This
LATE requirement caused NASA to derate the lift capability of the orbiter. It
has on occasion exceeded 20 tons to LEO and it has brought back payloads that
weigh more than HST (i.e LDEF)

The original rated capacity was 65,000 lbs to LEO with a direct injection
burn, this is still possible. It is my understanding that some space station
element flights will be as high as 44,000 to 47,000 lbs. They will of course
waive some of the constraints on the abort modes for these flights.

So the Shuttle is "capable" of lifting that much mass. Probably this could go
as high as 70,000 for a flight with ASRM's. Unless there is some strange
emergency this will never happen. There are no payloads heavier than SS Freedom
elements.

Dennis, University of Alabama in Huntsville

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

Date: Tue, 24 Nov 1992 14:38:26 GMT
From: Thomas Clarke <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman)
writes:
>
> Splash.
>
> Boom.
>
> Boom, boom.
>
> Classic mistake to abandon working hardware until flight
                            ^Booming^
> proven replacements for the capabilities are in place. No more paper
> spaceships please.
>
> Small confort to a crewed vehicle. Boom is boom.

I think (USSR?) Shuttle is only rocket to have killed crew during
the boost phase.  We've got to replace it before it happens
again.  Get rid of those damn SRBs.  If they're no good on a titan
then they're no good on the shuttle.  Everytime I watch a launch
I find myself holding my breath for the 2 minutes it takes to
expend the SRBs.

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
[phone], FAX: [phone], [e-mail]

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

Date: 24 Nov 92 15:19:15 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

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

>Spacelab and Astro are two payloads that we want very much to return
>from orbit on a regular basis.

No, Spacelab and Astor are two payloads that we want very much to keep
in orbit so they can be used. Building multi-billion $$ payloads and then
flying them for a few days every two years isn't cost effective.

>Not that they are all that
>cheap mind you, but the experimental community thinks them worthwhile.

The experimental community doesn't pay for them so this should come
as no suprise.

>Deadheading is never cost effective. But that's a management problem,
>not a Shuttle problem per se. If you have to charge an entire Shuttle
>mission against a satellite return, then it is expensive,

To date it has never been done. Shuttle flights are so expensive
that it isn't likely it can ever be done. You would need to return
at least five or so satellites.

>>A Titan IV launch costs about a third of what a Shuttle flight costs.

>Boom.

So? When a Titan goes boom the crew has a very good chance of surviving.
There hasn't been a Titan failure which would have resulted in loss of
crew for at least 10 and more likely 20 years.

When Shuttle goes boom on the other hand, people die.

>>The new Titan SRMs will close most if not all of that gap.

>Boom, boom.

Does the word 'Chalenger' ring a bell? Remember the old saying about
people in glass houses?

>That's the excuse used to abandon Saturn, Shuttle was supposed to be
>far cheaper. Classic mistake to abandon working hardware until flight
>proven replacements for the capabilities are in place.

Would you consider a pickup truck which only worked one day a week and
cost $200 per mile to operate 'working hardware'? I wouldn't which is
why I don't consider Shuttle working hardware.

>>In the last ten years or so almost all the boosters have been blown up
>>by range safety.

>Small confort to a crewed vehicle. Boom is boom.

If your in Shuttle, true enough. On the other hand if your in a Delta
Clipper made of much simpler components (less likely to fail) and with
abort modes throughout the entire flight envelope it is a great deal
of comfort.

A range safety officer can blow up a Shuttle, not so with Delta Clipper.

   Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------151 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 24 Nov 92 15:21:36 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

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

>>And as any Harrier pilot will tell you, a vertical powered landing is
>>safer than a horizontal powered landing.  And either one is *much* safer
>>than a Shuttle-style horizontal landing *without* power.

>As any glider pilot will tell you, gliders don't burn on impact.

Nither do Delta Clippers which are made of non-flamable composits and
have little fuel in them when they land.

>Nor do they pinwheel across the sky when a thrust diverter fails.

DC doesn't have thrust diverters.

Simplicity often = safety.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------151 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 24 Nov 92 15:22:50 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

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

>It's awfully hard to dock with an idea.

Not if your a good engineer.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------151 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

End of Space Digest Volume 15 : Issue 453
------------------------------