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Ladies and Gentlemen of the 51-L Jury



 
 
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  #41  
Old August 16th 03, 06:58 AM
Kent Betts
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Default Ladies and Gentlemen of the 51-L Jury

Alasdair McKie
Is your pursuit of the valve command info tied completely to the
crossfeed issue you know existed or does it relate to something else?


J Maxson
Both, obviously.


heh heh.....the jury is back. They found Maxson insane, but set the penalty at
hanging.


  #42  
Old August 16th 03, 07:07 AM
Alasdair McKie
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Default Ladies and Gentlemen of the 51-L Jury

In article , "John Maxson"
wrote:

Do you have nothing better to do than insult my intelligence?


I'm sorry that you feel I'm wasting your time. I've seen a lot of really
hostile language lobbed in your direction during the time that I've been
reading this group, and I've often wondered which came first - their
hostility or yours. In retrospect, I can honestly say to myself that I
haven't done anything to deserve this kind of response.

I can't help but feel that if you don't have the time for me, I don't
have the time for you. While I truly feel you are pursuing your
investigation of the events surrounding the loss of Challenger because
you want to know the truth and you want the world to know the truth, I'm
sorry to say you're closing another mind to your ideas.

-A

--
Remove .kil to reply by email.
  #43  
Old August 16th 03, 10:13 AM
John Maxson
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Alasdair McKie wrote in message
...
In article , "John Maxson"

There is a document linked from that post
(http://history.nasa.gov/rogersrep/v5p1227.htm) which also depicts
a chart showing Findings next to the item "RCS" as "Nominal"


How did you miss the column 'EVALUATION,' where it lists
"All Measurements Except Valve Commands?"

--
John Thomas Maxson, Retired Engineer (Aerospace)
Author, The Betrayal of Mission 51-L (www.mission51l.com)


  #44  
Old August 16th 03, 11:26 AM
Stephen Stocker
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Default Ladies and Gentlemen of the 51-L Jury

In article , Jon Berndt wrote:
"Stephen Stocker" wrote in message

In article , Chuck Stewart


The correct phrasing would seem to be "Would it have been possible?
And, if so, under what circumstances would it have been possible?"


Yep, at least on the first part. Under what circumstances would be my
next question. If I understand what I've read, while it's not normal
for such an event to occur, it *is* within the realm of possibility,
with any one of several sets of circumstances?

Steve


The question of whether or not the RCS could *possibly* be fired during
first stage when no abort has been declared should be an easy one to answer.
Here is what can be said based on information I have on hand at home:

1) The RCS training manual that is used by flight crews, instructors, and
flight controllers (publication RCS 2102 April 1987) states specifically
that the RCS is used for on-orbit manuevers, entry flight control, and
during ascent in "off-nominal situations" (engine failure aborts) for
augmented roll control (this includes the SERC capability mentioned by Jorge
previously). It categorically states that the vernier jets (the smaller
jets) are only used on-orbit for fine attitude control). This detailed 100+
page training manual states when the RCS is used. First stage usage when no
abort has been declared is NOT one of the situations in which the RCS is
said to be used. If there was a situation where RCS jets could be used
during nominal first stage, this manual would very likely state such.


OK. One minor issue which comes to mind is whether the manual
cited differs in any significant respect from the one used at the time
of the Challenger loss? A couple of other things are running around in
my head (extra space ), but they're sort of irrelevant in view of
the next two paragraphs...

2) The Ascent Guidance and Control manual (ASC G&C 2102) shows control
diagrams for nominal first stage flight. The outputs of the flight control
diagrams are to the SRB gimbal actuators and to the main engine gimbal
actuators. The RCS jets are not in the loop. A full description of RCS jet
usage for abort situations is given. If RCS jets were used in nominal first
stage, the document would very likely state such.

3) No purpose would be served by having RCS jets fire for control purposes
in nominal first stage flight. In fact, it's a ludicrous idea. Firing an RCS
aft yaw jet provides about 870 lbs thrust (vacuum), and provides a very
small rolling moment about the center of gravity of the stack. The same
effect can be achieved by gimballing nozzles on the ~2.5 million lb thrust
SRBs by 0.01 degrees. Really. Do you see what I am getting at?


Yes, and it probably would've been my *next* question. Whew, rereading
these figures. Sounds like pitting a car engine against a sewing
machine motor, only more so.

4) All of us here who have experience with the shuttle program and have been
immersed in it for years aren't simply barking out our asses when we say
that the RCS jets would not have been commanded to fire during first stage
flight when all the engines were still working and no aborts had been
declared. Can we point to a document that comes out and says specifically
"The RCS jets do not - and in fact are incapable of - firing during first
stage"? I cannot find one, but I do not expect to find one, because it is
accepted and understood that they do not.


I missed this when I first scanned through it. It touches on the other
point which I still couldn't pin down, which basically goes back to
the question of possibilities.

5) Regarding the recent JTM statement: "That's one of the first things I
verified on my job in the days following the disaster." I'm not sure how to
take that statement. Are we supposed to believe that John Maxson personally
verified that the software that was loaded in the GPCs on Challenger's last
flight specifically included code that fired the RCS jets (for
God-knows-what reason)? In light of what I know and what others have posted,
and given the kind of "proof" that I have seen in his book personally, I
have only one thing to say: prove it.


That was my *assumption* of what John meant, at least that the
software loaded was capable of firing them. But as someone pointed
out, that's all it is, *my* assumption. Whatever the case, it's
interesting to me, and I appreciate the time taken by all to make this
understandable to me. As I may have said in another post, I think
maybe it's easier for somebody like me, on the "outside" from a
technical standpoint, to really enjoy this type of debate.

6) The video/film clip from which the 51l images on the main page of
www.mission51l.com are taken from show an artifact that is visible in two
camera views and appears to emanate from the "top" SSME. This artifact is
not present in more obvious views from north located cameras. I have located
a volunteer who has agreed to host about 100 MB of .avi files of 51L
footage, within days, I hope. You will be able to judge for yourself.


Sounds great! The only video I've been able to find is fairly low
resolution and I'm the first to admit that my perception of images
isn't the greatest in the world.

Also, I wrote last week about inadvertent RCS firings and relayed that I
would provide the reference. So, here it is:

---

"Space Shuttle Avionics System", NASA SP-504, John F. Hanaway, Intermetrics,
Robert W. Moorehead, NASA HQ, 1989

pg. 44:

"If a thruster fires because of an incorrect command from one of the GPC's
or because of some other failure in a string, an opposing thruster or
thrusters controlled by other computers in the set will be commanded to fire
to counteract the erroneous torque on the vehicle. An appropriate alarm will
be sounded and the crew will be required to take appropriate manual action
to disable the uncontrolled jet before fuel use or other constraints are
violated."

...

"Misfiring RCS jets are detected by sensing the chamber pressure in the jet
each time it is commanded to fire, with an appropriate delay to account for
the pressure buildup. Continuously firing (failed on) jets are detected by
comparing the state of the computer command to a given jet with the voltage
applied to the solenoid drivers, which activate the fuel and oxidizer valves
causing the jet to fire. If the solenoid driver voltage indicates that the
jet is firing with no associated computer command, the jet is declared
failed on, the crew is notified, and the associated propellant manifolds
must be closed to prevent loss of fuel."


Finally, an area where I feel on solid ground! At least the principle
of it. The relative simplicity and elegance of things like that amazes
me. Multiply it by what, 100,000 or so, and you have the electrical
system of a shuttle? g

So, I am trying to pass along what several others have been helping with: no
RCS jets are believed to be commanded during nominal first stage, [extremely
unlikely] inadvertent firings would be handled by the flight software and/or
the crew, telemetry would show positive signs, etc.

There is no proof I am aware of that the RCS jets could fire during nominal
first stage flight for 51l, nor is there visual evidence they did, nor have
we seen telemetry evidence that there was.


And this, I think, is the only real issue of debate related to the
RCS? It helps me in more ways than one, as did your web site. I didn't
feel that it told me what I was seeing or not seeing, but rather gave
me a groundwork from which to start. Whether that was your intention
or not, I think it's a positive thing.

Argh, sorry about the short soapbox, and thanks again.

Steve
Jon


  #45  
Old August 16th 03, 02:28 PM
Stephen Stocker
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Default Ladies and Gentlemen of the 51-L Jury

In article , John Maxson wrote:
Stephen Stocker wrote in message
...
In article ,
Jon Berndt wrote:

Can we point to a document that comes out and says specifically
"The RCS jets do not - and in fact are incapable of - firing during
first stage"? I cannot find one,

snip
It touches on the other point which I still couldn't pin down, which
basically goes back to the question of possibilities.

snip
Are we supposed to believe that John Maxson personally verified
that the software that was loaded in the GPCs on Challenger's last
flight specifically included code that fired the RCS jets (for
God-knows-what reason)? In light of what I know and what others
have posted, and given the kind of "proof" that I have seen in his
book personally, I have only one thing to say: prove it.

snip
That was my *assumption* of what John meant, at least that the
software loaded was capable of firing them.

snip
There is no proof I am aware of that the RCS jets could fire during
nominal first stage flight for 51l, nor is there visual evidence they

did,
nor have we seen telemetry evidence that there was.


Can you make the same statement if you remove the word "nominal?"

And this, I think, is the only real issue of debate related to the RCS?


There is no "issue of debate" with me over any "nominal" 51-L ascent,
nor over any of the flights beyond Mission 51-L. The officials who
launched 51-L waivered at length over the unusual hazards involved.


OK. I *think* I'm still on the right track, even though the only thing
I can do is ask questions and try to learn something.

Pages 31-32 and 46-47 of my book (over which Berndt is in denial) tell
some of "the rest of the story" (as Paul Harvey would say), and I have
good reason to believe that anyone except someone as biased as Berndt
would find it extremely compelling.


I believe that everybody who knows the technical aspects of the
shuttle would have to be "biased", in the sense of having their own
opinions based on their experiences. Maybe I'm weird, but I also think
it can lead to quality debate, and I hope that's where this is
leading.

I do not intend to post all of that on USENET, however. Let me just
say that KSC made more last-minute changes to the 51-L flight software
load than for any prior mission, many without verification and proper
sign-off. There were many verbal waivers. I'll quote from page 31:

"Johnson waived a requirement to downlink the RCS data, and
an unusual Lockheed uplink accomplished the change."

Now whether that extended to the switch-scan data, I'm not positive;
but sources whom I trust felt very strongly that it should not have.


That probably answered Jon's question, if I understood it correctly.
(Please correct me if I'm wrong, my brain's tired!) And again, I
appreciate the information from both of you.

Steve

  #46  
Old August 16th 03, 03:00 PM
John Maxson
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Default Ladies and Gentlemen of the 51-L Jury

Stephen Stocker wrote in message
...
In article , John Maxson wrote:

Pages 31-32 and 46-47 of my book (over which Berndt is in
denial) tell some of "the rest of the story" (as Paul Harvey would
say), and I have good reason to believe that anyone except
someone as biased as Berndt would find it extremely compelling.


I believe that everybody who knows the technical aspects of the
shuttle would have to be "biased", in the sense of having their own
opinions based on their experiences. Maybe I'm weird, but I also
think it can lead to quality debate, and I hope that's where this is
leading.


Let's hope so. If they let post-51-L spin get in the way of finding
out what happened on 51-L, they are being subjective, not objective.
Since my most severely critical opposition is coming from folks with
post-51-L experience at JSC, one would think they would be objective
enough to obtain the waiver log and the waivers for 51-L as a starting
point for their understanding and argument of flight software issues.
I don't see that happening. They stonewall by putting up strawmen.

--
John Thomas Maxson, Retired Engineer (Aerospace)
Author, The Betrayal of Mission 51-L (www.mission51l.com)


  #47  
Old August 16th 03, 03:55 PM
John Maxson
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Default Ladies and Gentlemen of the 51-L Jury

Stephen Stocker wrote in message
...
In article , John Maxson wrote:

There were many verbal waivers. I'll quote from page 31:

"Johnson waived a requirement to downlink the RCS data,
and an unusual Lockheed uplink accomplished the change."

Now whether that extended to the switch-scan data, I'm not
positive; but sources whom I trust felt very strongly that it
should not have.


That probably answered Jon's question, if I understood it
correctly. (Please correct me if I'm wrong, my brain's tired!)


I don't know what his question was, so I'll confess that I can't. I
feel quite strongly that nothing will change his opinions/attacks.

I will say this, though. I don't trust any RCS telemetry from JSC
as being representative of what happened during Mission 51-L.
It's essentially worthless, being atmospheric pressure with KSC
readings in the operating range zeroed out except at the very end.

My 51-L RCS telemetry from KSC has values in the operating
range, one at a time not inconsistent with a plot in the PC Report.
Nevertheless, the 51-L House S&T technical staff was unable to
get 51-L RCS T/M from NASA Headquarters to confirm that
RCS firings occurred during Mission 51-L, so it was left *open*.

--
John Thomas Maxson, Retired Engineer (Aerospace)
Author, The Betrayal of Mission 51-L (www.mission51l.com)


  #48  
Old August 16th 03, 04:02 PM
James Oberg
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Default Berndt's Bias


"John Maxson" wrote in message news:bhkskr$1c2
How did you miss the column 'EVALUATION,' where it lists
"All Measurements Except Valve Commands?"


If the chamber pressures and temperature readings, and firing commands (as
opposed to valve commands) show no RCS action, that's pretty unequivocal.

NO RCS FIRINGS OCCURRED.




  #49  
Old August 16th 03, 04:03 PM
James Oberg
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Default Oberg Seeks Technical Explanation


"Jon Berndt" wrote in message news:3f3db788$0$64929
FWIW, I have actually seen TAL in some NASA docs as Trans-Atlantic

Landing,
although now everyone seems careful about calling it Transoceanic Abort
Landing.


True, some NASA people are human, but then how does that explain the TAL
abort from Vandenberg that we designed, into Easter Island or Hao?




  #50  
Old August 16th 03, 04:49 PM
James Oberg
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Default Ladies and Gentlemen of the 51-L Jury


"John Maxson" wrote in message
I will say this, though. I don't trust any RCS telemetry from JSC
as being representative of what happened during Mission 51-L.
It's essentially worthless, being atmospheric pressure with KSC
readings in the operating range zeroed out except at the very end.

My 51-L RCS telemetry from KSC has values in the operating
range, one at a time not inconsistent with a plot in the PC Report.
Nevertheless, the 51-L House S&T technical staff was unable to
get 51-L RCS T/M from NASA Headquarters to confirm that
RCS firings occurred during Mission 51-L, so it was left *open*.


This is a claim that is subject to rational documentation and proof.

Please show us your 51-L RCS telemetry records.

On what basis do you aver -- and what significance to you suggest -- that
some capitol hill staffer couldn't get some sort of document from HQ, when
actually the document would have come from JSC? And is "open" a status flag
in a published report, or is that more just verbal memory?




 




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