STS-114 Mission Update Thread (Part 2)

[yurkin]

Maybe this has been answered before but why don’t they just replace everything that might be causing it? It might cost a little more but they’d be sure to fix it.

 

[emerrill]

"I disagree, IMO media has been bombarding those NASA guys with guestions that almost beg them to just fly with 3/4."<br /><br />I think its a double edged sword. I think everone will be happy they got it off, but I think that there would be lots of editorials along the lines of 'NASA is back to sacrificing safety for time/money' <div class="Discussion_UserSignature"> </div>

 

[yurkin]

I think on the whole the media would be very friendly with the idea of launching with 3 over 4. The problem is that what if there is a failure that could have been prevented if they had launched with all 4? The same talking heads that had just commended Nasa would be damning it hell. The fallout would be just too terrible to think about.

 

[emerrill]

"Maybe this has been answered before but why don’t they just replace everything that might be causing it? It might cost a little more but they’d be sure to fix it."<br /><br />They have basicly aleady replaced everything they can. They are on their 3rd point sensor box if I remember correctly (there are no more), they have replaces most all of the wiring, and they have replaced the ET where the sensors are located. Now this was when trouble shooting the sensors in the opposite tank, but I beleive they did all the wiring for all 8 sensors (SG, S_RTF?) when they did it, and the point sensor box is shared between all the sensors<br /><br />-Eric <div class="Discussion_UserSignature"> </div>

 

[tap_sa]

Couple days after succesful liftoff the press don't even remember any ECO problems <img src="/images/icons/smile.gif" /> <br /><br /><br />edit: Aaaargh ... that motormouth presenting shuttle missions on NASATV <i>again</i>. I bet DDR had more versatile TV programme in the 70s <img src="/images/icons/tongue.gif" />

 

[shuttle_rtf]

The guy with the moustache? I like him. <br /><br />I thought his "Voting off Temptation Island" description for the Orbiter's Flight computers was hilarious.

 

[shuttle_rtf]

>They have basicly aleady replaced everything they can. They are on their 3rd point sensor box if I remember correctly (there are no more), they have replaces most all of the wiring, and they have replaced the ET where the sensors are located. Now this was when trouble shooting the sensors in the opposite tank, but I beleive they did all the wiring for all 8 sensors (SG, S_RTF?) when they did it, and the point sensor box is shared between all the sensors <<br /><br />I'm in no position to answer an engineering question...but to pass this on to add to the mix and leave that question for SG, etc.....<br /><br />.....I've been told by a few people (engineers) that something of interest - in regards to the fault tree - is the LH2 ECO sensor number 2 SIM circuit...an expansion of which I've written a story about. That element aforementioned would point to this issue being 'less than' intermittent - given the ECO issue being a problem and not a problem when that SIM switiched on and off respectively.<br /><br />Again, just passing that on....I'm just a writer! <img src="/images/icons/smile.gif" />

 

[redgryphon]

Now 7:15 pm EDT (11:15 pm GMT) for the press conference.<br /><br />The MMT must be going long!<br /><br />Edit to add: I'm relying on memory, but wasn't the test circuit the location of the suspect electrical components? (I can't remember if they were capacitors or resistors). The rest of the system was OK, and all the suspect parts had been replaced in other boxes, but they had left the ones on the test circuit because that's all it was. Or has this suspect been exonerated by now?

 

[shuttle_rtf]

Midnight 15 UK time. No sleep for me, again <img src="/images/icons/wink.gif" />

 

[ltm_se]

On NASATV:<br />Post MMT Press Conference<br />No Earlier Then 7:15 PM EDT<br /><br />Is EDT New Yorkish time or Houston time?

 

[lunatio_gordin]

East coast: New york, DC, the Cape.

 

[shuttle_rtf]

Now 7:30pm EDT. This sounds like they are having a fun MMT. That, or Wayne Hale's searching google for some extra colourful metaphors <img src="/images/icons/wink.gif" />

 

[lunatio_gordin]

actually, you posted that at 7:05 <img src="/images/icons/tongue.gif" />

 

[ltm_se]

Shuttle_RTF: Arn't you brittish and enjoying these "daylight" launches as much as me in the evenings here in europe?

 

[tap_sa]

Hejsan, GMT+3 här ... <b>8</b>-I

 

[ltm_se]

"Hejsan, GMT+3 här ... 8-I"<br /><br />Jasså, du är en nattuggla du oxo?

 

[shuttle_rtf]

I am British, but they could launch at 4am in the morning UK time and I'd still love it <img src="/images/icons/wink.gif" /><br />

 

[shuttle_rtf]

So, it seems they believe the issue was a grounding issue - electro-magnetic. They are going with 4 out of 4 for the launch, but if an expected 3 out of 4 issue comes up and they understand it, then they could go with that.<br /><br />Point sensor box got a few mentions. No Tanking Test now. Launch attempt Tuesday.<br /><br />More tests to be done. <br /><br />Sounds like they are using ECO Sensor 4 and 2 to test (if I heard right) on the swapping over to test each sensor.

 

[earth_bound_misfit]

Do you mean this one, from NajaB....<br /><blockquote><font class="small">In reply to:</font><hr /><p>I think it was an oblique reference to the Law of Unintended Consequences - it is possible that the recent problems are in some way related to the change of power supply path. One (silly) example of how this might be so - grounds. It's possible (though highly unlikely) that the point sensor box may be at a slightly different ground potential than the ECO sensors, where before they were all tied to the same common point. <p><hr /></p></p></blockquote> <div class="Discussion_UserSignature"> <p> </p><p> </p><p>----------------------------------------------------------------- </p><p>Wanna see this site looking like the old SDC uplink?</p><p>Go here to see how: <strong>SDC Eye saver </strong>  </p> </div>

 

[planet_z]

Just got back from my dinner break and saw this on the wires. Great news!<br /><br />AP-Space Shuttle<br /><br />Launch set for Tuesday<br /><br /> KENNEDY SPACE CENTER (AP) - Discovery has a new launch date,<br />Tuesday morning.<br /> Space shuttle program manager Bill Parsons says the launch is<br />set for "about ten-34 a-m" -- Eastern time.<br /> Problems with a fuel sensor caused a delay.<br /> Parsons says there's still "a great amount of work" to be done<br />between now and Tuesday. He says if the fuel gauge works properly<br />during the final hours of the countdown, the launch will proceed.<br /> If the problem recurs but is well understood, then the go-ahead<br />will likely be given to launch Discovery anyway.<br /> The shuttle fleet has been grounded since the 2003 Columbia<br />disaster over East Texas.<br /><br />(Copyright 2005 by The Associated Press. All Rights Reserved.)<br /> <br />AP-NY-07-20-05 2021EDT

 

[bpcooper]

I noted a few months ago that July 26 is an ironic date, as 10:39am is when STS-107 launched. More coincidentally, the launch times of 51L and 26 were 11:38 and 11:37am, respectively, (and that was by coincidence as well, as STS-26's launch was posponed about 90 minutes into the window due to a technical problem). <div class="Discussion_UserSignature"> <p>-Ben</p> </div>

 

[emerrill]

Ok. To some things up some:<br /><br />They are aiming for a launch at 1039a Tues the 26th.<br /><br />They have fixed a ground problem in the aft cargo bay.<br /><br />They are doing EMI testing tonight, testing a list of things that have changed since the last launch that could produce the EMI signature (they have reproduced signals that will cause the circuit to hang, and they are trying to find similar sources of EMI in the shuttle). If they find an EMI source, they have until about 24hrs into the count to fix the problem before the aft has to be closed out, or the launch delayed (unless it is an item that is off for launch, read more below).<br /><br />After every change to the shuttle configuration during the count that could interfere, they will test the ECOs. If the problem appears, then they will undo that last change to verify. If that is the problem, and that item is normally off for launch, then they will launch.<br /><br />They are switching the pinouts of sensors 2 and 4 at the point sensor box. If the problem re-appears as 4 (so really sensor 2 in the ET), then the problem is with the sensor/wiring and they are prepared to likely launch, and are currently preparing all the docs to make a LCC exception in that even. <br />If the problem shows up as sensor 2 (really sensor 4), and it is not narrowed down to a specific, EMI problem, then they will scrub because it means it is a problem in the PSB.<br /><br />Please feel free to correct me if im wrong on something here, but this is the jist i got from the news conference, and I just wanted to sum things up for people.<br /><br />-Eric <div class="Discussion_UserSignature"> </div>

 

[bpcooper]

http://www.spaceflightnow.com/shuttle/sts114/050720newdate/ <div class="Discussion_UserSignature"> <p>-Ben</p> </div>

 

[henryhallam]

If there are no problems detected and the launch goes off with 4/4 sensors, I wonder how much more troubleshooting will be done after landing (given that reflow for STS-301 has to be done in reasonable time). <br /><br />After all even though the grounding problem has been identified as a potential cause, it doesn't appear to be conclusive? Would hate for this to crop up again on future launches.

 

[emerrill]

From what i've seen, it seems like it was very likely a grounding/EMI problem (It seems that they were able to recreate it in huston with EMI, which implies a grounding problem). Im currious what SG has to say about that?<br /><br />-Eric <div class="Discussion_UserSignature"> </div>