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Subject: SPACE Digest V8 #329

SPACE Digest                                      Volume 8 : Issue 329

Today's Topics:
               Re:  Solar Sails
         SETI (was Re: Time dilation affecting SETI)
               The Challenger Disaster
----------------------------------------------------------------------

Date: 10 Aug 88 05:51:01 GMT
From: agate!saturn!ucscb.UCSC.EDU![e-mail]  (Space Cadet)
Subject: Re:  Solar Sails

In article <[e-mail]> [e-mail] (Steve Abrams) writes:
~    Doppler effect?  The Doppler effect arises from motion (in the
~frame of the observer) of a "source" with respect to an observer.
~While I agree that a solar sail moving away from the Sun will "see"
~red-shifted photons (and, hence, gets slightly less - for
~interplanetary sails - push, as the "peak" of the solar irradiance
~curve is red-shifted from around 490 nm), it doesn't depend upon
~their absorption and re-emission.  It wouldn't be a double effect as,
~when the photon is re-emitted, the sail would be both "source" and
~"observer."  Since the sail has no velocity relative to itself and the
~sail will never interact with that photon again, there is no Doppler
~effect with respect to emission.

     I meant a double doppler effect as observed from the original source
of the light (the sun, a laser launcher, etc.)
     I referred to the Doppler effect to explain why you would not be getting
"something for nothing": while the kinetic energy of the sail (and ship) will be
increased, the frequency of a reflected photon will be lower, as will its
energy.  Thus, energy has simply been tranferred from the photon the sail.
If one is looking for a non-rigorous explanation, I think this is the simplest
way to put it.  Note that as the velocity of the ship increases, the redshift
of the reflected photons increases; that is, more of their energy is
transferred to the sail.
--
> Hello, lift.   # We're going to space if we have to walk. -Jerry Pournelle  <
< -Marvin the PA # The meek will inherit the earth.  WE will go to the stars! >
> John H. DuBois III # [e-mail]  ...!ucbvax!ucscc!ucscb!spcecdt <

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

Date: 9 Aug 88 16:33:41 GMT
From: attcan!lsuc!ncrcan!hcr![e-mail]  (Edwin Hoogerbeets)
Subject: SETI (was Re: Time dilation affecting SETI)


Let's imagine for a moment that we want to send out a strong message in
the Hydrogen band to other intelligent life in the galaxy. Which way
would we send it?

I think it would be obvious to send it in the direction of the center of
the galaxy to reach the most prospective planets(?) where life would
exist.

Now think of *our* galactic location. We're on the edge of the galaxy.
Maybe we're just missing out on all the fun because we're on the
sidelines? Everyone is sending their message the other way! By the time
the messages from the other side of the galaxy get to us, they are too
weak to detect.

This assumes, of course, that a message is directional. You could
probably get stronger reception if the message doesn't spread thin as
in the shell example earlier, so it might be that everyone else is
sending directional messages to each other. Think of the infamous
transmitter aboard the Discovery in the book/movie 2001. AC Clarke made
that one directional, as it used less precious energy that way.

Another possible reason we might not be receiving came to me while
reading sci.crypt. Maybe everyone is sending RSA across the universe and
we don't know what's going on? (again :^) You might argue that we are
receiving statistically provable random noise. Does anyone have a proof
that all encrypted messages that can be statistically distinguished
from noise? If not, then this might also affect SETI.

Unrelated topic:

Has the person who is conducting the poll of significant space related
events finished said poll? I am interested in seeing the results ;-)

Comments anyone?

------ --------- = -------------------------------------------
Edwin (Deepthot)                      Waterloo co-op student, HCR Corporation
Hoogerbeets                           2A computer science and psychology
uunet!utai!utcsri!hcr!edwin                                  Me Tarzan, Unix.
                  edwin@hcr         //           Freudian slips? This message
or:                                //               contains no Freudian sex.
...!hcr!MsgPort!edwin          \\ //   Amiga        Glider pilots are experts
A B2000 running UUPC            \X/  Enthusiast             at keeping it up!

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

Date: 9 Aug 88 17:53:27 GMT
From: att!ihlpb!ihnp4!ihuxz![e-mail]  (D Woo)
Subject: The Challenger Disaster


-----------------------------------------------------------------------
The following article appeared in the May 1988 *Defense Science*.
-----------------------------------------------------------------------

            The Challenger Disaster
             by Dr. Yale Jay Lubkin

What we don't know can create problems, but even greater problems can arise
from what we think we know, but which is inaccurate.

The Rogers Commission investigating the Challenger incident seems to
have set out to create a body of facts that are not true. This is my
conclusion after reading Richard Feynman's dying declaration in the
February 1988 *Physics Today*. (Feynman died almost simultaneously
with the PT publication.)

The Commission was an almost typical Washington commission. Its head
was William Rogers, just about the consummate example of a Washington
insider. (Casper Weinberger, retiring as Secretary of Defense, has joined
Roger's law firm several rungs down the ladder from Rogers. Perhaps only
Clark Clifford can come close to Rogers in the class of political
lawyers.

Who made up the Commission? In the words of Senator Hollings, "So
who have ya got, there, on your commission? Ya got a couple of astronauts,
a Nobel prizewinner, a general, some businessman and a couple of
lawyers. What you really need is gumshoes, who will be right down
there at Kennedy, eating lunch with the very guys who do work on the
Shuttle."

Rogers actually had a gumshoe, whom he could not suppress. Feynman reports
that Rogers did his best to keep the Commission from finding any disturbing
facts, tried to sit on Feynman, and then tried to freeze him out. It
didn't work. Feynman had a bone and he wouldn't let go. Feynman eventually
issued his own report, differing substantially with the preconceived
notions of the Commission. And probably killed any chances for future
independent thinkers to appear on Presidential Commissions.

I feel sure that Mr. Rogers would have been much more comfortable with
Henry Hudson, of the Meese Pornography Commission, who replied to criticism
that that commission had reached unscientific conclusions: "If we relied
exclusively on scientific data for every one of our findings, I'm afraid
all of our work would be inconclusive."

Or with OSHA, who, right after Challenger, gave NASA a citation for having
the best government workplace safety record.

There seems to be much to hide. Feynman lights up a lot of bureaucratic
garbage at NASA. CYA is running rampant.

Questions: The Challenger incident leads one to ask many questions. Since
one can draw any conclusion from a false premise, the first question
is "Just what happened?" This is hardly trivial, but the experiences
of Feynman and AbuTaha lead to a second question: "Why are the authorities
trying so hard to prevent the answer to the first question?" The third
question is "Why did it happen." The answer to the forth question is
self-evident. "If NASA is fixing the wrong problem, what happens
next time?"

Let me introduce Feynman and AbuTaha. Richard Feynman was a Nobel Laureate
in Physics. More importantly, he was a great physicist with an informal
manner and a driving curiosity. Alone of the members of the Rogers
Commissions, he had the intelligence and the drive to find out answers,
was beholden to none and was afraid of none. He viewed his job as only
finding out the truth.

Read his dissenting report and read his article in *Physics Today*. Read
between the lines as to the purpose of the Rogers Commission, and remember
what William Rogers is. (Also read the extensive article by Trudy Bell
and Karl Esch in the *IEEE Spectrum* of February 1987.)

Ali AbuTaha is a space engineer, with ten years' experience at Comsat,
plus another few there as a consultant. He has been a space consultant
for some time. He read the Challenger Commission report simply for self-
education, but his curiosity was excited because when he found a large
number of "specific disparities, errors and mistakes." And a few outright
lies. He dug into it at his own expense, and spent two years of time
and thousands of dollars. He got a second, third and forth
mortgage. He hunted up reports and videos tapes from non-NASA observers
and processed them, and formed a theory. He transmitted this to NASA.
They first dismissed him as a kook for daring to question official dogma,
then tried to destroy his reputation by ad hominem attacks, then appro-
piated some of his findings and passed them off as their own.

You can understand some of what happened by reference to Figure 1, from
Feynman's article. The figure shows the joint between 12-foot diameter
sections of the booster. The upper section has a lip that fits into a
clevis in the lower section. The leak of hot gases quite clearly came
from that section of the joint between the bottom and middle sections
of the booster which was next to the main rocket. (The O-rings are
on the inside.) NASA and the Rogers Commission say that the O-rings lost
resiliency because of the cold and allowed a 20 mil leak, starting
0.67 seconds into the flight, mysteriously closing at 3.52 seconds, then
disastrously re-opening at 58.8 seconds.

Feynman says that this isn't true. Morton Thiokol goofed on the design,
and knew it. The internal pressure of the rocket was supposed to squash
the O-ring into a good seal. Problem was that the joint was much stronger
than the rocket wall (it was three times as thick), so instead of the
joint deforming, the wall deformed, lifting the O-ring away from the
joint, and allowing the leak. So Feynman's theory calls for a continuous
leak.

The Thiokol engineers knew the joint was no good, and tried a bunch of
fixes. They went to Parker Seal Company, who made the O-rings, for
advice. Parker said that O-rings weren't supposed to be used that way,
and no advice was given.

One makeshift that Thiokol used was to shim the outer portion of the
joint, as shown in Figure 1. Unfortunately, the outer lip is much lighter
than the middle, so instead of squashing the O-ring, the shim just
bent the outer lip outwards.

Ali AbuTaha has the most convincing theory. The lower section of the
booster had been used in a previous flight. There is a strut connecting
the booster to the external tank, and this strut is located just below
the joint. There are tremendous forces on this strut, on the order
of a miillion pounds, and the strut pulls on the side of the booster.
The forces of the previous flight bent the the bottom section out of
round, by 0.512 inches according to measurements (apparently by Lockheed
personel) at the Kennedy Space Center.

This meant that the midsection would not fit into the lower section. The
midsection was apparently round. As far as AbuTaha can tell, the Lockheed
people used a hydraulic press and adjusting nuts mounted in the middle
section the middle section together to distort the shape so that it matched
the out-of-round section. This seems to have caused a crack at the edge
of the middle section, which then leaked continuously during the
flight. Flames are clearly visible on the enhanced videos during most of
the flight. AbuTaha provided 39 enhanced photos of the leak, flame,
etc. to NASA on August 12, 1987.

Instructions were to limit the hydraulic pressure to 1250 lb, which was
done, but there were no instructions as to how much pressure should be
exerted by the adjusting nuts. Nobody ever measured.

The leak caused a side thrust, diverting the Challenger from the proper
course. The Challenger control systme put a correction in the loop, to
cancel the side thrust. This caused the whole system to hunt, as can
be seen from the time sequence of position shown in Figure 2. The
Challenger oscillated. Each oscillation put tremendous stress on the
strut, on the order of millions of pounds. The oscillations are clear
from the shape of the exhaust plumes.

The strut and the control system oscillation flexed the booster wall
in and out, each time causing the release of hot gas. Eventually,
the continued violent flexing caused the entire strut support structure
to break off, letting the flame hit the Challenger directly, killing
some of the crew and causing the explosion. (Some of the crew were
apparently alive at moment of impact.)

It was not the leak that killed the astronauts. It was the attempt to
correct the sidethrust, which sent the Challenger into violent
oscillations. If the Challenger had been permitted to go off course,
without attempting the major correction, the side of the booster would
not have broken out, the booster would have burnt out eith the Challenger
still intact, and the crew could have ejected, off course but alive.

AbuTaha has thousands of pages of documentation and many photographs
and video tapes to prove his contentions. We have room to show only one
photograph, taken from a video made at New Smyrna Beach by Harold
Sehnert of Ohio. The photograph, Figure 3, is fifty or sixty seconds
into the flight. Note that the intermittent nature of the puffs is clearly
visible. Many stills can be seen in the March 1987 issue of the British
magazine *Spaceflight News*.

Note that one similar shot was used by the Commission in its report,
but it has been cropped to exclude the puffs. The twin plumes were present-
ed as coming from the two boosters, rather than from the boosters and
the leak, as is obvious from the film. One universed in the subtleties
of Washingtonspeak might call this a deliberate lie.

The NASA Reaction. In bureaucratese, the NASA reaction was pure CYA. A
Supreme Court justice said it was not only necessary to do justice, it
also was necessary to give the appearence of doing justice. NASA does
not seem to be doing either.

For example, Malcom McConnell, in his book *Challenger*, (Doubleday,
1987) just about accuses two NASA bigwigs of severe conflicts of
interests. He accuses Dr. James Fletcher, periodic NASA Administrator,
of being a member of the Mormon Mafia who threw the booster contract
to Utah-based Thiokol, despite their inferior product and lack of
experience. He also blasts Dale Myers, who alternated between being
Deputy Administrator of NASA and a high Rockwell executive, for pushing
the Challenger award to Rockwell in still-secret proceedings.

Now McConnell exhibits a left-wing, anti-Republican bias, but he does
raise valid questions and does appear to have been stonewalled by the
NASA legal eagles. He notes that Aerojet was able to make one-piece
boosters, and thus avoid an entire set of problems due to Thiokol's need
to use multiple segmented rockets. He notes that the McDonnell-Douglas
orbiter proposal included and abort motor which would have seperated
the orbitier from the stack, allowing it to glide back to the landing
site in event of booster failure.

But AbuTaha was not engaged in politics. He was engaged in engineering.
And NASA trashed him, then stole his ideas.

In July 1986, for example, AbuTaha reported his finding that Challenger
was operating with negative safety margins for loads at lift off, backed
it up with analyses and sent the data to NASA. His findings were rejected
with comments like, "It is unnecessary to pursue the thoughts contained
in this report," (John Thomas, Oct. 30, 1986), and, "The loads and stresses
measured prior to and during launch match those predicted within nominal
tolerance," (Richard Truly, Nov 12, 1986).

In a memo to Fletcher on January 15, 1987, the National Research Council
was talking about negative safety margins. But in March 1987, AbuTaha
was still receiving comments from NASA of "not plausible" and "NASA finds
no new evidence in any of your analyses that could change the original
sequence of events or the cause of the accident," (James Rose, 13 March
1987) while NASA was presenting AbuTaha's findings as their own.

It is also not especially clear how cold weather could have caused four
O-rings to be damaged on Launch 51-B, including almost complete burn-
through of the primary O-ring on the left booster nozzle joint. The
launch temperature for that lauch was a balmy 75 F.

It is not especially clear how the NASA and Thiokol executives attained
their perspectives on the mission. Feynman questioned many people about
their estimate of probability of mission failure. Working engineers
typically estimated about one in a hundred. Executives estimated about
one in a hundred thousand; i.e. one failure could be expected in a
sequence of one lauch a day for three hundred years. Do executives get
a daily fix? Feynman stressed that NASA officials had been living in
a world of unreality.

The Commission reported incredible paperwork sloppiness (P220). They
found that half the paperwork was flawed, including 96% of Work
Authorisation Documents. Why? The Commission stated categorically, "The
system ... is an impediment to good work and good records." Has anything
changed?

It was not only the paperwork that was sloppy. The Viton O-rings were
specified for use between -30 F and +500 F, but NASA never seems to have
tested them.

It is not clear that any of the people responsible for all of this sloppy
work, poor management, political sleeze and unreality have paid for
it. Certainly not Fletcher or Myers or Young. Certainly not NASA or
Thiokol, who received millions more as a result of the Challenger
incident. (I do not call it an accident. It was a disaster waiting to
happen.) The people who were punished were Roger Boisjoly and Allan
McDonald, who tried to prevent the disaster.

It is clear that another investigation, run by engineers, not lawyers,
might be in order, maybe even a book with a lot of photographic evidence
left out of the Commission report.

The final words of Feynman's report are important: "For a successful
technology, reality must take precedence over public relations, for
nature cannot be fooled."

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

End of SPACE Digest V8 #329
*******************