Text 1983, 217 rader
Skriven 2005-08-15 20:22:43 av mark lewis (1:3634/12.0)
   Kommentar till text 1978 av WAYNE CHIRNSIDE (1:123/140)
Ärende: NASA, shuttle, anyone?
==============================
->  WC> All four worked intermittently, 

-> not according to what i've seen... it was the backup sensor 
-> to the backup sensor that failed in the testing done during 
-> the launch countdown... they were unable to reproduce the 
-> failure during later testing after going into the system to 
-> try to track down the failure...     

 WC> Every sensor is the backup for the other three and that's a fact. 

oh? so which one is the primary? and where is this fact stated?

[trim]

->  WC> Had the sensors failed again as they had before as nothing 
->  WC> had been done to fix them it's possible the sensors would 
->  WC> have indicated fuel it was running out.

->  WC> This would lead to the flame from the engine nozzels being 
->  WC> sucked back into the combution chambers, BOOM.

-> wrong... the indication of lack of fuel would shut down the 
-> engines and they would not have made it to orbit... 
    
 WC> I expressed myself poorly.

not a problem... been done many time before by all of us O:)

 WC> Had the sensors indicated fuel when there was none the shutdown
 WC> signal would not be sent and the situation I described could have
 WC> occured. It's why those sensors exist in the first place, or so
 WC> said a NASA engineer.

right... however, the problem was that the sensor(s) were indicating no fuel
when there was a full tank... so different problem, actually...

-> the failure was a "no fuel" indication when
-> the tanks had fuel... not an indication of fuel when there was none...

 WC> Any intermittent failure is unpredictable and with a half million 
 WC> gallons of liquid hydrogen and oxygen there's little room for
 WC> error. 

with a _known_ full tank and one sensor telling them it is empty, that sounds
pretty predictable to me...

 WC> The chief Morton Thiokol engineer had authority to stop the
 WC> shuttle Challenger from flying due to his expressed concerns about
 WC> the cold's effects onthe o ring seals in the SRB's.

 WC> He was overruled and the shuttle Challenger blew up.
 WC> Being an embarrassment for telling the truth he was fired shortly
 WC> thereafter.

 WC> Engineers, quite a few of them, expressed deep concern about the
 WC> deris that hit the Columbia's wing after liftoff. The lower rank 
 WC> engineers had no avenue to express their concernes to flight 
 WC> managers. Later their e-mails all came out reveasling their 
 WC> concerns very early on after the liftoff. Another shuttle lost by 
 WC> ignoring evidence at hand :-(

yes, i've extremely aware of all this (other than the engineer being fired)...
i have archived recordings and texts of much of it, if not all of it... i'm
very into this stuff and have a couple of satelite dishes set up where i can
specifically acquire the NASA TVRO signals... the 10 foot mesh has two sets of
recievers connected so that i can watch/record two channels off one bird... the
other dish is a direct tv dish that i get the same as one of the channels off
the 10 foot mesh... i won't even mention the "tracking" dish i have connected
to a soundcard and tracking software for grabbing images and other data
transmitted O:)

->  WC> This is generally considered a bad thing.

->  WC> Also a repair to a dent in the shuttle's tank was repaired after
->  WC> the foam was removed. Foam was replaced but it was deemed 
->  WC> unnecessary to inspect the affected area.

->  WC> As it happens foam from this area detached during launch to orbit. 

-> i have the video and pictures... the problem i have with what you
-> are saying is that the same thing happened on the other side of the 
-> tank where the other SRB was mounted... so that's two foam 
-> detachments... not just one... methinks that some are confusing some 
-> things...                       

 WC> There were FIVE foam detachments, one was just over a pound
 WC> and had it struck the orbiter earlier in denser air it could have
 WC> disabled it for a sucessful landing.

that is a possibility, yes... i agree... however, we're talking about the large
(two of them) detachments that came off back around the bottom SRB mounts...
those had little chance to harm the shuttle...

-> ->  WC> Shuttle not rolled back but delayed.

-> -> so... don't have to rollback to fix a problem...               

->  WC> Don't worry they didn't. 

-> i'm not worried... i was saying that there does not have to be a
-> rollback to fix a problem... i left off the word "you" in front of 
-> "don't"...

 WC> You do if you want to go inside the tank where the fuel sensors are
 WC> and actually diagnose what's wrong with them, or so said NASA. They
 WC> flew on a wing and a prayer instead.

obviously you don't because they didn't... they pulled the sensor(s) and
connected them to testing hardware and had at them for days... when they
discovered nothing, they put them back in place and tested again for more
days... still nothing showed up...

oh, and who said they had to roll back to get inside the tank(s)?? i'm sure
there are accessible man hatches somewhere on the vehicle... at least if the
sensors are inside the tank(s)...

->  WC> They flew the shuttle without a clue as to what had caused the
->  WC> problem. 

-> ->  WC> Intermittent problem with the faulty fuel sensor never pinned 
-> ->  WC> down it happened to be working when they launched after 
-> ->  WC> deciding to override their own safety rules.

-> -> when did they decide to override their rules? i don't recall that 
-> -> and i watched and recorded most all of the NASA TV broadcasts...     

->  WC> It was repeatedly announced after the initial delay and after they
->  WC> failed to pin down the intermittent fuel sensor problem,

-> it was announced that they were overridding their safety rules?? i
-> definitely do not remember that specific wording... 

 WC> They said they would fly with three operating sensors in direct
 WC> violation of safety regulations requriring all four be working. 

interesting... i dunno if i'll go digging about for that, though... it is not
that important, really... the mission flew and was highly successful... i have
absolutely no problem with that at all...

->  WC> It just happpened the sensor didn't fail during the runup to
->  WC> launch, very fortuitous.

-> are you positive that it was a sensor failure? they aren't...

 WC> they were getting a false reading intermittently and they checked
 WC> the wiring and swapped the wires from differing sensors never
 WC> finding the source of the failure.

that still doesn't point to the sensor being the problem... were they able to
get the error any more after they first got into the wiring?? i don't believe
so... however, there's a lot that they haven't told everyone in their
conferences and press meetings...

[trim]

 WC> I finally found the ground fault, it was in the high - low beam
 WC> selector button on the floor and a new one cured the problem.

glad you found that or we'd not be having this _friendly_ discussion today ;)

-> ->  WC> Now the tank's burned up returning to Earth we'll never know why
-> ->  WC> the sensor malfunctioned.

-> -> one suggestion was a ground problem because the problem never
-> -> happened after the initial discovery... could also have been a 
-> -> loose connection... either way, they apparently fixed it while 
-> -> getting to it and studying it...              

 WC> Could have been this, could have been that, could have been
 WC> anything. Know what blew up Apollo 13's service module that nearly
 WC> killed the crew and aborted their moon landing?

yup, sure do...

 WC> There was a heated in one of the oxygen tanks to vaporize the
 WC> liquid O2 to fuel the fuel cells in the cold of space.
 WC> That heater was specified to be 24 volts, it wasn't.
 WC> It was spec'd 12 volts. An astronaut following standard procedure  
 WC> turned on the heater and a moment later the stirrer,
 WC> Seconds later the oxygen tank expoded taking much of the
 WC> despirately needed service module with it.
 WC> Astronauts lived in the LEM lander sick and cold in that craft not
 WC> designed for the job to save what kittle was left of the capsule
 WC> for the last monments of re-entry.

yes, i've read the reports and seen the movie many times <shrug> ;)

->  WC> Ground problems are FAR from trivial as an electrical _circuit_
->  WC> requires a return to function. In my personal experience ground 
->  WC> problems are actually the worst sort of problem.

-> yes, they can be... i've done my fair share of them over the years ;)

 WC> They can kill you rather quickly even here on Earth.

yup... i've been a ground more than i care to think about... i really hate
being the ground path when discharging picture tubes... that's one bite that
hurts like hell... not only is high voltage a problem, but so is high
amperage... i can cause some real pain with 9 volts and a high amount of
ampreage O:)

->  WC> I spent months tracking down an intermittent ground problem in  a
->  WC> stereo amplifier once.

-> -> what else was sloppy??

->  WC> See above.

-> besides that...

 WC> They launched in spite of the known problems.

and that was sloppy? sounds almost corporate or government to me ;)

)\/(ark

 * Origin:  (1:3634/12)