Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_4/V15NO458.TXT

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Date: Thu, 26 Nov 92 05:02:33
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #458
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 26 Nov 92       Volume 15 : Issue 458

Today's Topics:
                   Computer synchronisation by GPS
                      Evil wicked flying bombs!
             HST and management (was Re: Hubble's mirror)
                         HST black hole pix?
                           Hubble's mirror
                      Magellan Update - 11/20/92
                   manned vs. unmanned spaceflight
                      Shuttle Computer Problems
                     Shuttle replacement (7 msgs)
                         Space suit research?

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: Wed, 25 Nov 1992 19:23:24 GMT
From: "Michael K. Heney" <[e-mail]>
Subject: Computer synchronisation by GPS
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
> [ GPS theory and practice ... ]

>The usual sorts of synchronization protocols go to great lengths to deal
>with the problem of *not* having a common absolute time reference.  With
>GPS, you *have* a common absolute time reference.  All GPS receivers,
>anywhere in the world, agree on the exact instant when the GPS system
>clock reads 1:45:67.8727634 (with several more decimal places if the
             ^^^^^^^^^^^^^^^

When all GPS recievrs agree on that particular time, the system is broken!



--
Mike Heney                |   Senior Systems Analyst and     |  Reach for the
[e-mail]   |  Space Activist / Entrepreneur   |  Stars, eh?
Kensington, MD (near DC)  |     * Will Work for Money *      |

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

Date: Wed, 25 Nov 92 16:12:10 -0600
From: [e-mail] (Phil G. Fraering)
Subject: Evil wicked flying bombs!

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

/Goodbye Disney World. A flying bomb with no destruct sequence isn't
\acceptable.

/Gary

Personally, I kinda find the lack of an autodestruct on all those
747's to be unacceptable.

My uncle John once opined that 18-wheelers would be driven much
more safely if they were all wired up with an appropriate amount
of semtex.

Fine, you don't want to land it near Disney World? Fine. We put the
spaceport someplace like West Texas. We'll probably have to anyway,
since by then spaceflight may be against the Earth Protection Laws
or some such nonsense ;-)

Phil Fraering
"...drag them, kicking and screaming, into the Century of the Fruitbat."
<<- Terry Pratchett, _Reaper Man_
--
Phil Fraering
"...drag them, kicking and screaming, into the Century of the Fruitbat."
<<- Terry Pratchett, _Reaper Man_

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

Date: 25 Nov 92 12:18:44 -0600
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: HST and management (was Re: Hubble's mirror)
Newsgroups: sci.astro,sci.space

In article <[e-mail]>, [e-mail] (Joe Dellinger) writes:
> In article <[e-mail]>, [e-mail] (Greg Hennessy) writes:
> |> PE developed a system of testing that they
> |> THOUGHT would be good enough. Unfortunately it was not. At least we
> |> can be pretty sure that this blunder won't be repeated.
>                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> But... PE's system of testing WAS good enough. They had three
> redundant tests, so that if one test gave a false OK the other
> two could catch it.
[...]
>
> The blunder was that the people paying for it weren't checking
> over the shoulders of the ones being paid.

Ah, but "the system was designed to work this way."  NASA was trying
to build an inherently expensive and high-performance system, the
Space Telescope, as cheaply as possible, so they cut a lot of corners.
In this case they kept the NASA staff supervising the project small
and gave the contractors a lot of autonomy.

People on the Net, and in the general press, often praise streamlined,
low-paperwork project management... the popularity of the phrase
"skunk-works" is one example.  When it works, the results are
wonderful and great value for the money. Fermilab's construction was
supervised by a cowboy physicist, and his gang finished the Main Ring
ahead of schedule and under budget.

When it goes wrong, though, the risks of this approach become
apparent.  Hubble ran into big management troubles in the early
Eighties, long before the mirror problem was detected.  It was
finished pretty much by throwing massive amounts of money at the
problems, which negated the penny-pinching efforts of its early years
and ended up costing way over a gigabuck by launch day.  See Robert
Smith's history *The Space Telescope*. (But wait a bit.  It's coming
out in paperback soon, in a revised post-launch, post-spherical-
aberration edition which includes more Tales of Woe and Intrigue.)

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

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

Date: Wed, 25 Nov 1992 18:19:30 GMT
From: Henry Spencer <[e-mail]>
Subject: HST black hole pix?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Or, does anybody know where such a file could be obtained by
>anonymous FTP?
>
>NASA? STSI? anyone??

NASA/STScI doesn't release HST images in digital form until after the
one-year period allowed for the experimenters to publish papers on them.
Occasional significant images do get released early for publicity, but
only in hardcopy.  (This policy is a bit silly, admittedly, in an age
of cheap scanners...)  Unless somebody's scanned it in, you're out of luck.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Wed, 25 Nov 1992 19:23:37 GMT
From: Henry Spencer <[e-mail]>
Subject: Hubble's mirror
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (William H. Jefferys) writes:
>#... three independent tests were run, and TWO OF THEM DETECTED
>#THE ERROR.  At which point, Perkin-Elmer management decided that the third
>#was more trustworthy than the other two, and ignored the two failed tests.
>
>The tests to which you refer are the refractive null and
>the inverse null, in addition to the faulty reflective null.
>All three of them are based on the same basic interferometric
>technology, and are not independent in the sense that I
>meant...

Okay, point taken -- more diversity in tests is desirable.  However...

>...Had they measured the position of
>the field lens with a PLASTIC RULER, it would have been found.
>There were lots of red flags flying, and they were all ignored.
>
>By an independent test, I meant a geometric-optics test such as a
>Hartmann test that could have, fairly cheaply, detected the problem...

Ah, but would it have been believed?  That's the crucial problem.  My
impression is that it wasn't "we've got three similar tests, and the
best one says we're okay", but rather "we've got three tests, and the
best one says we're okay".  The trick was not detecting the error --
after all, it *was* detected -- but detecting it in a way that would
have been sufficiently emphatic and unmistakable to make P-E doubt
their beautiful reflective null corrector.

The point of an end-to-end imaging test, in this context, is not that
it's an easy way to detect the problem, but that it's so hard to
argue with.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Wed, 25 Nov 92 19:22:43 GMT
From: Doug Mohney <[e-mail]>
Subject: Magellan Update - 11/20/92
Newsgroups: sci.space,sci.astro

In article <[e-mail]>, [e-mail] (hiroki hihara) writes:

>We procured many parts from the United States for Hiten, and they
>are proven to be strong enough against such environment.
>
>-- NEC Space Systems Development Division
>   Hiroki Hihara

Can I quote you on that?

                :-)

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: 25 Nov 1992 13:06:59 -0600
From: John David Regehr <[e-mail]>
Subject: manned vs. unmanned spaceflight
Newsgroups: sci.astro,sci.space

Sorry if this is a dead subject, but I've only been reading this group for a
week or so.  I'm writing a paper contrasting manned and unmanned spaceflight.
I'm in the middle of a couple of books, but I haven't been able to come up
with a good thesis statement yet.  I would appreciate hearing from people who
have opinions on the subject, or who can suggest some good reference material.
I am trying to approach this from a practical and philosophical standpoint,
rather than detailing the historical controversy on whether the focus of space
exploration should be on manned or unmanned flights.  Thanks.

-----------------------------------------------------------------------
John Regehr    [e-mail]
Kansas State University
-----------------------------------------------------------------------

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

Date: Wed, 25 Nov 92 22:04:01 GMT
From: [e-mail]
Subject: Shuttle Computer Problems

I also had a few run-ins back in the late 70's that we basically
figured were SEU's but never had any proof thereof.

You probably know it already, but ceramic type chips have enough
natural radioactive decay to cause more problems than most cosmic
rays. Local beta decays cause a good bit of ionization, and the paths
can be large enough to flip a bit. I have a file on this somewhere,
although as I remember it is actually quite slim, ie I've not seen a
whole lot published on the subject.

I would expect that the people who really know are the ones at the
national labs who tested components in high radiation environments of
nuclear weapons tests. Probably all rather classified...  Jordin???

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

Date: 25 Nov 1992 11:55 CST
From: [e-mail]
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes...
>In article <[e-mail]> [e-mail] (Dan Vento) writes:
>
>>> No, Spacelab and Astor are two payloads that we want very much to keep
>>> in orbit so they can be used.

>We want to bring back individual experiment racks. We don't want to bring
>back the entire lab.
>

This is like saying we want to bring back the windshield wipers not the whole
car after a rain.


>>if not most of the Spacelab type payloads are very new concepts, flying for
>>the first time, often built by organizations with little space hardware
>>experience. Rethinking and reflight are part of the learning curve.
>
>Exactly. Those users are ill served by a Spacelab which flies one time
>every couple of years. They WOULD be well served by something like
>ISF which is up there all the time and so offers far more flight
>opportunities.

Nope ISF does not exist and therefore does not serve anyone. Spacelab has
flown three times theis year and will fly at least that many times per
year until SSF gets to PMC. SpaceHab also will be serving the microgravity
material processing community starting on STS57  in April of 93. No Allan
the shuttle is getting more and more viable as we work to drive down the
costs of the experiments by using more and more commercial hardware that
could never be flown on recoverable capsules. WE are flying a Macintosh II
SI for a system controller for our experiment on SpaceHab I and II. We will
also fly it on Spacelab SLS II next time.


>
>>Remember the Shuttle type small Space Experiments world (except for life
>>sciences) has really only been around since the late 70's
>
>I hope you aren't referring to 'get away specials' since NASA doesn't fly
>them anymore.
>

Hey Allan wake up. We have flown three here from UAH in the last 18 months and
will fly five more in the next 18. There have been over 50 GAS payloads in
the last 2 years and the que has just opened up for a new round.

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

Date: Wed, 25 Nov 1992 17:52:22 GMT
From: Henry Spencer <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>There are ELVs with worse records that shuttle's, but I think there are also
>a few with better records.

A very few.  The Saturns are the only ones that come to mind.  The last
few years haven't been good for expendable reliability records.

>Actually, I'm not sure the shuttle has abort modes for the very first part of
>flight and I know that most people don't consider certain abort modes
>survivable.

There is no officially-sanctioned abort mode while the SRBs are burning,
last I heard.  (Oh, you might try SRB jettison or orbiter/ET separation,
but the orbiter won't survive either one.)  It was looked at during early
design, and again after Challenger; that is a *hard* problem.

Once the SRBs burn out, you can try an RTLS (Return To Launch Site) abort,
which is essentially a hypersonic U-turn, but the pilots consider it
unsurvivable or nearly so.  An alternative, also fairly unappealing, is
to ride the orbiter down to low altitude and bail out into the Atlantic.

There are times during post-SRB ascent when a multiple engine failure is
unsurvivable, because the orbiter is too high and too slow and will hit
atmosphere too hard.

The first really attractive abort mode is the transAtlantic abort, with
a landing in Spain or Africa.

>[Soyuz]  In fact, some of the
>pictures I've seen seem to have escape rockets on unmanned payloads.  Am I
>mistaken or is there a reason for this?

One doesn't normally put escape rockets on unmanned missions, because
there's no point in incurring the hazard to the pad crews unless you're
rescuing something important.  A major exception is unmanned tests of
hardware intended to be manned.  A second exception is systems originally
designed to be manned, in which the escape rocket's jettison sequence
accomplishes something useful like pulling a payload shroud off.  I
believe the Progress freighters launch with an escape rocket for that
reason.

>>L-1011's flown in without elevator controls.  United almost landed
>>a DC-10 minus an engine and all controls.  Convertibles have been landed.
>
>Convertibles?  Do you fly them with the top down?

He's referring, somewhat obscurely, to the Aloha Airlines accident where
a 737 lost half the top of its fuselage and was landed safely.  There have
been one or two other less-dramatic incidents.

>... DOE once did a test of the flammability of hydrogen and gasoline.
>They filled two eight foot balloons with hydrogen gas and gasoline vapors
>resectively and then fired tracers into them.  The gasoline balloon ignited
>immediately and exploded in all directions.  It took three tracers to ignite
>the hydrogen balloon which then burned upwards for thirty seconds without the
>flames ever touching the ground.

Most people don't realize that (a) half the people aboard the Hindenberg
survived, and (b) many of the fatalities were due to the fall rather than
the fire.  If you look at the standard photograph, you see a big impressive
ball of fire... billowing *upward*, away from the airship.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Wed, 25 Nov 1992 16:18:48 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>No, gliders don't burn on impact; they just go "crunch".  It's still
>just about as fatal.

Actually it's not. The safety record for gliders is quite good, and they
don't burn blocks of apartments on the ground when they do smack in
like the *powered* Navy jet did in Marietta last year, or the *powered*
C-130 that *burned* the hotel in Evansville did this year, or the Israeli
jet freighter in the Netherlands.

>Neither airliners nor rockets "pinwheel across the sky when a thrust
>diverter fails".  A Titan launch a few years ago had one of the core
>engines lose gimbal control and lock in position (just about hard over
>to one side, I believe it was); the other engine compensated and only
>the technical crew noticed -- the launch was successful.

But you mentioned *Harriers*, and *they* have lost thrust on one side
and *have* pinwheeled, and *have* crashed and *burned*. Helicopters,
another VTOL, also have lost tail rotors and spun into the ground. I've
covered two such crashes in the last year. The pilots would probably
have survived, if they hadn't *burned* to death. Airliners aren't
VTOL aircraft, and rockets going *up* have room for a bobble in their
course without smartly contacting the ground. Rockets coming *down*
are an entirely different issue. An engine or control failure means
a crash of a vehicle containing *rocket* fuel, perhaps miles from
intended touchdown, like main street in Disney World for example.

I'd feel a lot better if they landed these suckers at sea, far out
at sea. And that's not a crazy idea. There have been proposals for
sea launched and sea landed space vehicles. Sea Dragon comes to mind.

Gary

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

Date: Wed, 25 Nov 1992 16:32:46 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] (Gary Coffman) writes:
>>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.

When the only other available alternative is to stay home, yes I'd
consider it working hardware. Deliver 50 out of 51 successful flights
on different hardware with the same capabilities and lower cost, then
we can talk about working hardware.

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

Goodbye Disney World. A flying bomb with no destruct sequence isn't
acceptable.

Gary

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

Date: Wed, 25 Nov 1992 18:15:34 GMT
From: Henry Spencer <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>>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.
>
>I seem to remember several satellites that were returned and later launched
>on other vehicles.

Exactly two, and that mission was financially feasible only because NASA was
itching to try it and gave the insurers a *very* good deal.  It was worth
doing once for the experience -- for one thing, we learned yet again that
human hands are much more reliable than automatic machinery when you're
doing more than just snapping pictures -- but could not be justified as
an operational (as opposed to experimental) mission.

>Also there was LDEF that is contributing greatly to
>lowering the cost of all of the other spaceflight missions due to the
>information gathered about the effects of materials in a long term LEO...

As Allen has pointed out, we'd have been better off flying several smaller
LDEFs over varying periods.  Some of the LDEF experiments were completely
ruined by being in space *too* long.  (For that matter, before you get too
enthusiastic about LDEF, please bear in mind that

    (a) it was meant to be reflown several times for varying periods
and    (b) it was meant as a general-purpose way to fly cheap experiments,

and it has not met either of those hopes and never will.  The undeniably-
useful information from LDEF is being had by sifting the ashes of the
original mission plans.)  Nobody denies that returning things from space
is useful now and then in small amounts, but bringing back (say) one LDEF
pallet at a time is not difficult without the shuttle.

>>... 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.
>
>Uh this is kinda strange when you think of all of the complex piping and
>fittings and multiple engines on the bird. Seem to me that there is more
>of a chance of a random or otherwise failure.

Of course, if you're flying in a Delta Clipper, it has been test-flown
before you were allowed on board.  (That *same* vehicle has been tested,
not just the general design.)  A 747 is considerably more complex than
a Delta; it is also considerably more reliable, because it can be tested.

>One good aspect of this is that
>DC is robust enough to compensate for the failure, unless they miswire the
>controllers like they did on the first Saturn V flight.

It was the second Saturn V flight, and note that the Saturn V survived it
and a DC probably would too...

>>A range safety officer can blow up a Shuttle, not so with Delta Clipper.
>
>Hate to bust your bubble on this one but on ANY launch from ANY facility
>operated by the US government, range safety can push the boom button whenever
>they see the mission deviating sufficiently from its mission parameters. DC
>will not be an exception for this.

This is one reason why operational DCs would not fly from US government
missile ranges.  (There are lots of others, like enormous bureaucracies,
stupid regulations, and massive costs.)  The FAA does not require or
permit range-safety charges aboard airliners -- yes, even when they fly
from airport facilities operated by the US government -- and DC-1 will
not be an exception for *this*.

Yes, McDD has talked to the FAA about certifying the DC-1 as an airliner,
and last I heard, the FAA was interested and cautiously willing.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Wed, 25 Nov 1992 19:27:40 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:

>Allan, dost thou have a reference for your "multibillion dollar" statement.

Spacelab alone cost $1B. Add in the cost of Astro plus flights and other
work and we are talking billions.

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

>The experimental community does pay for the instruments in the spacelab, and
>they also put several years of their lives into the effort.

We where talking about launches. The experimental community doesn't pay
for launches. Do you think the Italians would have paid the hundreds
of millions in actual cost for their payload launch in the last Shuttle
flight? I think they would have said 'hell no' and launched on a Pegasus
for an order of magnitude less $$.

Now if NASA goes ahead with the authorized voucher program, we may
see this change.

>>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.

>I seem to remember several satellites that were returned and later launched
>on other vehicles.

You are referring to the two Palpa communication satellites. It was about
all the Shuttle could do and it cost the taxpayers hundreds of millions
in launch subsidies.

We spent half a billion $$ to recover $75 million worth of satellites. Only
a NASA employee could consider that a good deal.

>Also there was LDEF that is contributing greatly to
>lowering the cost of all of the other spaceflight missions due to the
>information gathered

ERROR: You are assuming LDEF as is was the one and only way to get this
infromation. This is incorrect.

>you this is not figured in Allans accounting but it is in mine where my
>reliablity is greater for the information.

If you read my stuff in the past you will see I do include recovery of
LDEF type payloads. I simply do it in a different (and much cheaper) way.

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

>Last I heard Titan IV flights were $281 million according to Space Week.

That is including a Centaur upper stage. Configured in a similar manner
the cost is about a third.

>Your
>own figures Allan put the Shuttle cost at $500 million per flight. Take a
>look at the fraction, its kinda closer to 1.8 to 1.

Even if true, so what? We are still talking about a factor of 2 cost
difference. If your goal is to keep us all on the ground, by all means
buy the expensive one. On the other hand, if you want to open up the
space frontier, you got to reduce costs.

Which are you Dennis?

>>So? When a Titan goes boom the crew has a very good chance of surviving.

>Not so the Titan that blew up about 100 ft above the pad a few years ago.
>There was zero warning, the SRB's just went poof

Still a good chance of survival. All the pilot needs is 1/2 a second
to hit the button (rest assured his hand would have already been on it).

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

>yep its called the cost of doing business

Agreed. But that doesn't change the fact that capsules are safer than
Shuttle.

>>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.

>We are not talking about pickup trucks

It's called an analogy. If you don't know what that is or can't deal with
it, then remove this part of the thread. Otherwise tell us all if you
think the truck works.

>>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.

>Uh this is kinda strange when you think of all of the complex piping and
>fittings and multiple engines on the bird.

Compared to what? DC has fewer engines than Shuttle and needs less to support
them. Hell, even the DC RCS uses the same fuel as the main engine! Not only
does Shuttle have more engines, but it has four different types of engines.

Shuttle supporters who think DC is complex should go back to engineering
school.

>DC is robust enough to compensate for the failure, unless they miswire the
>controllers like they did on the first Saturn V flight.

Delta Clipper is fully reusable. That means it isn't likely the
controller was miswired. If it was miswired, the DC couldn't have
flown to the spaceport.

DC is no more complex than a 747. 747 techs rarely mess up the
hardware.

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

>Hate to bust your bubble on this one but on ANY launch from ANY facility
>operated by the US government, range safety can push the boom button whenever
>they see the mission deviating sufficiently from its mission parameters. DC
>will not be an exception for this.

DC-X will have charges. DC-Y may have charges but DC-1 will not have
charges. It won't need them any more than airliners need them.

You got to change your mindset Dennis. You won't make it as long as you
continue to equate more money and more complexity with better.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------150 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Wed, 25 Nov 1992 19:36:06 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:

>>>> No, Spacelab and Astor are two payloads that we want very much to keep
>>>> in orbit so they can be used.

>>We want to bring back individual experiment racks. We don't want to bring
>>back the entire lab.

>This is like saying we want to bring back the windshield wipers not the whole
>car after a rain.

Your getting confused. A car is a transportation device. A lab isn't. A car
*was designed* to move. Lab's aren't.

When I go home from work, I bring whatever papers I need and maybe a book or
two. I don't bring back my entire lab. If I did, I would need a much larger
and far more expensive car to go home in. Special roads would need to be
built just for me and it would be very very expensive. Worse, my co-workers
could only use the lab when I saw fit to bring it back to work.

This is why I prefer to keep my lab where it is. I can only wonder why
you feel the need to reduce productivity and increase costs by dragging
it everywhere and preventing others from using it.

>Nope ISF does not exist and therefore does not serve anyone.

You know, I'll bet that if somebody said that Freedom does not exist
and therefore does not serve anyone you would disagree.

>the shuttle is getting more and more viable as we work to drive down the
>costs

Care to document any cost savings?

   Allen


--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------150 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 25 Nov 92 17:46:05 GMT
From: "Charles R. Martin" <[e-mail]>
Subject: Space suit research?
Newsgroups: sci.space

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

   In article <[e-mail]> [e-mail] (Bruce Dunn) writes:
   >> Apparently anything significantly below 3 psi partial pressure of oxygen
   >> is a potential health risk, unless you have many generations of ancestors
   >> who lived in the mountains.

   I'm not sure what you mean by "significantly", but this certainly doesn't
   apply to ~2 to 2.5 psi oxygen: The residents of Aspen, many (most?) of
   whom have zero generations of ancestors who lived in mountains, live
   and work at such oxygen pressures, with no visable problems. Further,
   people with no hereditary _or_ personal adjustment to low pressures
   routinely go they to ski (which, if anything, requires slightly above
   normal consumption of oxygen.)

Frank -- Bop down the hall and talk to Igor Gamow (and give him my
regards -- it'll confuse the hell out of him since I was a student of
his Many Years Ago).  Anyway, actually a significant number of people
develop altitude sickness even at Aspen and *lower* altitudes.  Growing
up in Alamosa, I know there were people there who never adapted and had
to leave for medical reasons even though they were to all appearances
healthy; Robert Heinlein's wife Ginny had altitude sickness in Colorado
Springs that eventually forced their move to California.
--
        Charles R. Martin/(Charlie)/[e-mail]
     Dept. of Computer Science/CB #3175 UNC-CH/Chapel Hill, NC 27599-3175
        3611 University Dr #13M/Durham, NC 27707/[phone]
     "Oh God, please help me be civil in tongue, pure in thought, and able
      to resist the temptation to laugh uncontrollably.  Amen." -- Rob T

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End of Space Digest Volume 15 : Issue 458
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