Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_2/V11_226.TXT

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Subject: SPACE Digest V11 #226

SPACE Digest                                     Volume 11 : Issue 226

Today's Topics:
       Re: Reports of Io's vulcanism before VOYAGER 1?
          Re: Will we lose another orbiter?
        Re: HST Image Status for 04/01/90 (Forwarded)
          Re: Will we lose another orbiter?
              Re: National Space Society
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Date: 5 Apr 90 17:08:01 GMT
From: optilink![e-mail]  (Clayton Cramer)
Subject: Re: Reports of Io's vulcanism before VOYAGER 1?

In article <[e-mail]>, [e-mail] (N = R*fgfpneflfifaL 04-Apr-1990 0856) writes:
>
>         Were there any science reports, or even science fiction stories,
>     which "anticipated" volcanic activity on Jupiter's Galilean moon Io
>     *before* the flyby of VOYAGER 1 in 1979?  Please give details and
>     sources, thanks.
>
>         Larry Klaes  [e-mail]

Sure.  I wrote a science fiction story when I was in sixth grade, part
of it set on Io, that clearly included evidence of volcanic activity.
Just call me prescient. :-)

Look hard -- I'll bet you'll find plenty of examples of science
fiction that assumed (for the wrong reasons, like I did) that the
satellites of the outer planets were essentially terrestial in
nature.  Until the space missions, there was no reliable mapping
of the outer planets, and even the masses and diameters of the
Galilean satellites were highly uncertain.

We lose so much opportunity for science fiction close at home, the
more we learn. No bug-eyed monsters, no hothouse swamps on Callisto. :-)
--
Clayton E. Cramer {pyramid,pixar,tekbspa}!optilink!cramer
Politicians prefer unarmed peasants.  Ask the Lithuanians.
----------------------------------------------------------------------------
Disclaimer?  You must be kidding!  No company would hold opinions like mine!

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

Date: 5 Apr 90 14:15:52 GMT
From: cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!nic.MR.NET!timbuk![e-mail]  (Lou Adornato)
Subject: Re: Will we lose another orbiter?

In article <[e-mail]> [e-mail] (Wayne D. Johnson) writes:
> In article <[e-mail]> [e-mail] (Lou Adornato) writes:
>
> =>In the light of basic probability, I don't see how a lower "risk" factor can
> =>be justified.
> =>
> =>Consider a single component with a reliability of 99.9999% (which is pretty
> =>good even for a small, simple component, like a rivet).  The chance of this
> =>part failing is one in 10,000.  If there are 1000 of these parts, then there
> =>is 1 chance in 10 that one of them will fail.  If you put a million of them
> =>into the system, then you have to expect that 100 of them _will_ fail.  In
> =>order to maintain a 98% safety margin, you have to increase the per-unit
> =>reliability by _three_ orders of magnitude.  Do you have any idea how to
> =>make a rivet 1000 times more reliable?  Keep in mind that making it
> =>heavier might reduce the reliability of some other component.
>
> That is assuming that the mission will fail if any of the parts fail.  The
> main reason for redundant systems is to limit the failure rate by increasing
> the number of parts that may fail.  By having 3 redundant engines, failure of
> 1 critical part in 1 engine will not cause a "failure".  You probably know all
> of this, I'm just thinking out loud.

I intentionally left out redundancy because it would have clouded the
issue, but since you asked for it...

Redundancy is only a part of the solution, and in some cases it
introduces it's own problems, not the least of which being increased
weight and cost.  Apollo 13 had 3 fuel cells and three oxygen tanks.
The explosion of one tank took out all of them.

If you have two identical systems, the probability of both failing is
the square of the probability of one failing, plus the probability of
the one failure inducing a failure in the backup.  Vis:

P(f1) = x        Probability of independent failure on part 1
P(f2) = y        Probability of independent failure on part 2
P(f1|f2) = xy + xX + yY        Probability of parts 1 _and_ 2 failing
       ^^    ^    ^
       ^^    ^    ^---------Probability of f2 causing f1
       ^^     ^
       ^^     ^---- Probability of f1 causing f2
       ^^
       ^^---- Probability of coincident independent failures

Take as a f'rinstance is the SSME's.  There are three, and each one has
a high speed turbopump at the top.  If the fan disk on one suffers a
metal failure (keep in mind we're dealing with cryogenic gases here),
it'll disintegrate and blow shrapnel through its rotational plane,
which includes the other two engines.  In this case, the redundancy has
backfired - if we give each disk a 2% probability of failure, then the
probability of all three failing independently is .0008%, but with the
probability of inducing failures (X or Y above) approaching 1, the
probability of a total system failure is 6.0008%.  Fortunately, these
sorts of linkages are relatively rare, and the turbine disk has a
_very_ low failure rate.

Another big problem: how do you put redundancy into software?  Even with
harware voting and a backup flight system, a design (or code) error in the
primary avionics system could destroy the orbiter before the backup
could take over.

> It might be a good idea to think about updating the design to start removing
> some of the risks as we are building a new shuttle.

A lot of the risks are simply inherent in the mission; there is always
going to be a finite failure rate.  The only way for it to be
completely safe is to not do it.  For what it's worth, I've been
thinking along the same lines for a while, although I'm not sure that
there's enough operational data available yet.  I'd also put in the
requirement of maintainability.  Of course, it's not like our opinions
are going to make NASA start an operations review.

Lou Adornato    |  Statements herein do not represent the opinions or
Cray Research   |  attitudes of Cray Research, Inc. or its subsidiaries.
[e-mail]    |       (...yet)

P.S. To everyone who pointed out my stupid spacing on my original posting,
the problem has been fixed.  To all of you who simply cursed my name, same
to you.

Lou

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

Date: 5 Apr 90 16:02:12 GMT
From: idacrd![e-mail]  (Robert McGwier)
Subject: Re: HST Image Status for 04/01/90 (Forwarded)

From article <[e-mail]>, by [e-mail] (David Hafken):
>
> Hi. could someone tell me how to view the jupiter picture posted earlier on
> a macintosh? e.g. how to convert it and what prog. to use to view it.
> Any help would be greatly appreciated.
>


FOR CRYING OUT LOUD,  look at the date on the submission.  How the hell
do you think they mounted the space telescope and pointed it at Jupiter?

The quality of the picture (which has April fools date written in the
lower left corner) is easily exceeded by amateur astronomers and backyard
telescopes.  I have done so many times with my 16" Newtonian and have

nice prints from those days when I lived in a darker location and had
the telescope in an observatory.  The field of view of the HST is very
small, just think about what it takes to snap a photo of jupiter from
the ground when it has NO TELESCOPE MOUNT.  APRIL FOOLS about evewhere.

Bob


--
____________________________________________________________________________
    My opinions are my own no matter    |    Robert W. McGwier, N4HY
    who I work for! ;-)            |    CCR, AMSAT, etc.
----------------------------------------------------------------------------

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

Date: 5 Apr 90 14:14:24 GMT
From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!nic.MR.NET!timbuk![e-mail]  (Lou Adornato)
Subject: Re: Will we lose another orbiter?

In article <[e-mail]>[e-mail] (Paul Dietz) writes:
> In article <[e-mail]> [e-mail] (Lou Adornato) writes:
> >
> >Throughout my lifetime, we Americans have had a growing tendency to leave the
> >"details" of the technology on which we depend to "experts", and then turn
> >on the "eggheads" when anything goes wrong.  A case in point is the present
> >attitude about the original launch rate.  It seems that the clarity of our
> >hindsight is now considered proof that NASA was actively lying.
>
> Actually, the original launch rate (60) was demonstrably absurd.
> There wouldn't have been a budget big enough to buy that many
> payloads.  But NASA supplied bogus numbers anyway.  And any rational
> observer just before Challenger would have seen that NASA couldn't hit
> 24 flights/year -- they were stretched to the breaking point as it was.
> Read the Rogers report.

The original launch rate was set before any empirical data was
available.  At the time it was thought that economy of scale would have
dropped the per kilogram cost to orbit, and this would in turn cause an
increase in demand.  These projections where done before anyone
realized that the turnaround time on an orbiter was never going to come
down past a certain point (in other words, before the orbiter design
was complete).  They where based on overly optimistic thinking, but
this doesn't necesarily mean duplicity.  I'm willing to give them the
benefit of the doubt.

If NASA had managed to get to 24 launches a year, this would have been
called "pushing the envelope", or "a can-do attitude", and they would
have been considered heros.  There's nothing inherently wrong with
trying to exceed past performance.  It's when you let this become the
_only_ objective...

Of course, none of this excuses NASA for less than forthright behavior
when it became clear that the projected launch rate was unrealistic.
And none of this addresses the matter of the technological ignorance
of the public.  I still think that it's a good idea for a society with
nuclear capability to deal with technology in a manner substantially
different from superstition.

>
> >The launch rate had little to do with the Challenger disaster.  A slip of a
> >few days wouldn't have had that big an impact on the annual launch rate that
> >NASA was pushing at that time.  The direct cause of the accident was a mindset
> >by a handful of Huntsville managers that put the Thiokol engineers in the
> >position of having to _prove_ that it was unsafe to launch.
>
> This is false.  The alternative was waiting until April ("My god,
> Thiokol,..."), when the weather would be warm enough to not be out of
> the range of previous experience.  If they had held, they would have
> had to have held for months, not days.  More broadly, NASA had been
> ignoring the booster problem (and other problems) for a long time,
> in the face of repeated warnings.

If waiting three or four months was the only safe way to launch then
the entire responsibility is on Thiokol for not raising a red flag
months (not hours) before the launch.  Unfortunately, the alternative
was never waiting till April.  The "My God.." comment was hyperbole.  I
lived in that area for four years as a kid and _never_ saw ice that
didn't come from a machine.  Central Florida experiences that kind of
weather four or five times in a decade, and only once or twice in a
decade out on the east coast.  It would probably have been warm enough
to launch in 48 hours, assuming that the no rainwater had accumulated
and frozen in the joints.

As for ignoring the problem, I agree.  The first time that there was
evidence of a primary ring failure, the whole fleet should have been
grounded and the joints redesigned.  Any fairly competent failure
effects analysis would have shown what could happen if the secondary
failed.  At the very least, the evidence that the secondary had also
failed should have triggered this event.  As I said, I think that
criminal charges should have been filed.

>
> >I'm not going
> >to be cast as apologist for these idiots.  As far as I'm concerned, they
> >should have been liable to criminal prosecution.  But the real source of the
> >"must do" mindset was a desperate desire to stay off the critical path,
> >fueled by the public belief (which goes all the way back to the 60's) that
> >launch delays are caused either by bumbling or fraud.
>
> Your remarks *do* cast you as an apologist, no matter how you deny it.
> The responsibility for a safe launch rested on NASA, and nowhere else.
>

I guess I walked right into that, and probably the only way I can
redeem myself at this point would be to boil someone in oil.  I'm going
to try one last time.

NASA was certainly responsible for the safe launch of the Challenger,
and as an organization it messed up.  There's no arguing this, and I
won't try.  The organizational forces that drove the failure mechanism
included institutional arrogance, complacency, internicine squabling,
and oversensitivity to public impatience with launch delays.  My
original statement was intended to point out that willful public
ignorance of technology was a contributing factor in the last of
these.  An analogy would be a child egging another to touch a high
voltage wire.  This doesn't excuse NASA (or, rather, the portion of
NASA involved with shuttle launches - let's be fair to Goddard, Ames,
Lewis, etc); NASA _should_ have known better, and the public had no
idea what it was asking for.  But public ignorance did play a part in
the tragedy, and it's the _only_ factor that has yet to even get lip
service.

>
> >Dealing with overblown expectations isn't as easy as you make it sound.  NASA
> >is currently in the process of trying to downscale the public expectations
> >of the space station.
>
> Yes, let's give a big hearty cheer that NASA, eight years into the
> space station program, finally decides to add up the EVA requirements.
> They must have misplaced their calculators before.
>
> And let's give a nice big Gold Plated NASA Managment Hat Award to
> Lenoir for his cavalier dismissal of the report when it leaked out.

I haven't seen any space station designs coming out of Rochester.  Must
be harder work than you thought.  Keep in mind that a lot of the data
on erosion rates is fairly new.

For all the cockiness and bluster, it seems to me that all Lenoir
has said is that the projected problems are not unsolveable, which
statement _could_ be based on a fairly rigorous analysis, even 48 hours
after the original report came out.  He definately stated this with
more confidence that we outsiders feel was prudent, but with NASA's
present image problem, any other stance would have been tantamount to
asking congress to shut down the whole project (which is premature).

Once again it's a response to the inability of the average American to
understand technological risk - the public doesn't want to acknowledge
the possibility of failure, and so you have to make them think that all
of the problems are solved before any money is spent to solve those
same problems.  In ten years I've had at least three projects shot out
from under me by semi-technical managers (again, not here at Cray),
because I didn't play this game right.  Lenoir is dealing with a
congress that has the cumulative math understanding of moss; they'll
only listen to two answers:  a) It's too risky, or 2) There's no
danger, all is well.

(BTW - I caught just as bad a case of whiplash as every other NASA
watcher when I discovered that the development of the hard suit was
back on.  I also think that Livermore should get a shot at a competing
station.  It also looks like a full study is being mounted to look into
this, with a final report due in July.)

>
> >Just as an aside, how much funding do you think NASA would have gotten for
> >a safety redesign of the already unpopular shuttle if it had grounded the
> >entire fleet in '86 _before_ the accident?
>
> I see, Lou; lying is ok if it preserves your program and budget.  I
> think they would have gotten some, but the space station would have
> been in danger.  So they didn't ask.

I didn't say anything about lying, I asked how the long suffering
American public would have responded to a scenario that _should_ have
happened.  Your guess is as good as any on this, but I personally think
that it would have been a lot uglier.

The space station was in the same state in '86 that it had been in
since 1964 (i.e., science fiction) and wouldn't have been in any more
danger.  I think that the press would have had a field day with that
request, and the congress would likely have accused NASA of extortion
and refused any new funds.  The Regan administration would have simply
fired everyone involved and brought in people who would have continued
to launch.

I still stand by the point that public ignorance of technology is a
Bad Thing, that it played a part in the tragedy, and that, if public
faith in _all_ technology is shaken by the loss of one shuttle, it
points to a problem that goes far beyond anything NASA has done.

Lou Adornato    |  Statements herein do not represent the opinions or
Cray Research   |  attitudes of Cray Research, Inc. or its subsidiaries.
[e-mail]    |       (...yet)

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

Date: 6 Apr 90 00:10:32 GMT
From: vsi1!hsv3![e-mail]  (Mike Van Pelt)
Subject: Re: National Space Society

In article <[e-mail]> [e-mail] (Dave Smith) writes:
>I got a "survey" from the National Space Society today that really annoyed
>me for a number of reasons.
...
>I really dislike such childish attempts to manipulate me into sending money.
>This kind of "survey" is best aimed at the people who answer Ed McMahon's
>letters and think they will win something.
...
>I filled out the survey with answers showing a support for space
>exploration and a vote of "no confidence" for NASA ...

That's what I did with that piece of junk mail, filling the
questionaire with proper answers to its questions in all the blank
spaces.  (I *HATE* questionaires that try to force me to give
multiple-choice answers to essay-type questions.)

Not that I think it will do any good; the NSS "leadership" doesn't give
a hoot about the opinions of its members (or, in my case, ex-member),
as that bogus "questionaire" proved.  What the heck, it was on their
quarter.  If the survey hadn't come with a postpaid envelope, I
probably wouldn't have bothered.

(((WOW!  I'm listening to the news as I write this, and Pegasus finally
   went off today!  Now that's the start of something that might have
   some REAL impact on getting us into space.)))
--
Mike Van Pelt      Headland Technology/Video 7     ...ames!vsi1!v7fs1!mvp
"... Local prohibitions cannot  block advances in military and commercial
technology.... Democratic movements for local restraint can only restrain
the world's democracies, not the world as a whole." -- K. Eric Drexler

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End of SPACE Digest V11 #226
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