STS-114 Mission Update Thread (Part 2)

[marslauncher]

I agree totally, at least give the crew practice and if all is go for launch then take it. (as long as there is no risk)

 

[shuttle_rtf]

It could well be the case. All I've heard is another tanking test with the ECO's switched around. (again, looking for more info).

 

[robot_pilot]

We were told this morning that another tanking test could be performed as early as this Friday, or the weekend.<br /><br />Will post when I hear more...

 

[Leovinus]

Would they do a tanking test on just the O2 (or just the H2) tank? or would having one hot and one cold tank be too much thermal stress on the whole ET? <div class="Discussion_UserSignature"> </div>

 

[robot_pilot]

It would be both tanks filled simultaneously.

 

[shuttle_rtf]

Just to add to the ECO sensor swapping around comment I posted. It would be (according to source) ECO Sensor 1 (LH2) and ECO Sensor 2 (LH2) that would be 'swapped' with each other (I'm sure there's a more techinical term!).<br /><br />There is a concerned comment of this potentially affecting any 3 out of 4 reduction in the ECO Sensor flight constriant....if say both sensors 1 and 2 then have issues, becoming a 2 out of 4 - and thus scrub. But I don't know if that concern (from a USA guy on our forum) is a bit "reaching" given nothing is official.

 

[SpaceKiwi]

<blockquote><font class="small">In reply to:</font><hr /><p>Might as well make that tanking test an actual launch attempt.<p><hr /></p></p></blockquote><br /><br />I agree entirely, but they never will because of the public perception. It's a no-win for NASA. You put Astronauts on the Orbiter in the hope of getting nominal ECO sensor performance and you get questions from the press about safety to the crew if you do get away, or further ridicule if you don't.<br /><br /> <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[scottb50]

That's what they just tried to do. It was a gamble that didn't pay off, but was worth the try. To try it again doesn't make a lot of sense unless they are ready to waive the four funcrioning sensor rules. <div class="Discussion_UserSignature"> </div>

 

[bpcooper]

Well I've been absent from here because I've been down there...eight long days for nothing, but it was still fun... That is, setting up cameras and attending all the events (just not seeing everyone packing up and leaving!).<br /><br />I have posted FIVE galleries of my photos here:<br /><br />http://www.launchphotography.com/STS114firsttry.html<br /><br /><br />Enjoy. <div class="Discussion_UserSignature"> <p>-Ben</p> </div>

 

[shuttle_rtf]

Launch no sooner than the 26th - and that's optimistic. (paraphrased) - Wayne Hale.

 

[bpcooper]

The jist of it is, that if they don't find the problem in the next two days, they will consider fueling on the 26th and launching if the sensors work. If they don't work again then likely September. They may also do a scrub tanking test, regardless of whether they work, where they add some instruments to record data on the sensors; those would have to be removed the next day and then go launch. <div class="Discussion_UserSignature"> <p>-Ben</p> </div>

 

[bpcooper]

Check out the latest here:<br /><br />http://www.spaceflightnow.com/shuttle/sts114/050718options/<br /><br />I think this shows that a launch attempt next week is becoming likely. <div class="Discussion_UserSignature"> <p>-Ben</p> </div>

 

[lunatio_gordin]

he said they won't be tanking before tuesday. but that's still giving us a possibility of next week launch and making this window.

 

[marslauncher]

WOW what an awesome article! a bell was rung when I saw this part though... <br /><br />"A modification was proposed several years ago and implemented during Discovery's last major overhaul, eliminating the single-point failure mode. This will be the first flight for the modification. In the downtime after the 2003 Columbia disaster, engineers discussed changing the LCC back to three-of-four, but ultimately decided to let the rule stand as is. " <br /><br />This will be the first flight for the modification.....????? MEBBE thats why its not working, A new modification to a 30 yr old system....

 

[marslauncher]

hehe <img src="/images/icons/wink.gif" />

 

[marslauncher]

" a review of shuttle systems revealed that two of the sensors were powered or controlled by a single component in an electronic black box "upstream" of the sensor system. Because the failure of that component could take down two sensors, the rule was changed to require four-of-four at launch. <br /><br />A modification was proposed several years ago and implemented during Discovery's last major overhaul, eliminating the single-point failure mode. This will be the first flight for the modification. In the downtime after the 2003 Columbia disaster, engineers discussed changing the LCC back to three-of-four, but ultimately decided to let the rule stand as is. "<br /><br />What I meant by that was that they have changed items on the Orbiter with direct relation to the sensors, it hasnt been "flight tested" per se and I was just wondering if that could be one of the lines they were investigating, I mean whether or not the splitting of the system to allow each sensor to work independantly could have caused a glitch in the flight readiness software checks?<br /><br />didnt mean to take anything out of context.<br />

 

[najab]

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.

 

[robot_pilot]

I'm probably just repeating what you guys read in that article but I thought I'd add what I know about this week's (and next week's) activities. Just more verification here.<br /><br />I got an E-mail from my manager that basically says to be prepared to work a tanking test a week from tomorrow (i.e. Tuesday the 26th), and if they isolate the problem with the sensors then we need to be prepared for one or more launch attempts starting about three days afterward (starting a week from this Friday, or thereabouts).<br /><br />I'll get more details when I get back to my office on Wednesday, and I'll be very happy to share what I know with everyone then.

 

[robot_pilot]

The only hardware changes (that I know about so far) they'll make for this tanking test - assuming it happens - is the switchout of LH2 ECO #1/#2 pins. This is just part of the troubleshooting plan, and one of my USA colleagues told me that he thinks this will really help pinpoint the problem. As much as I would love to see instrumentation all over every square inch of the vehicle, it probably won't happen unless they can do it externally to the system, e.g. the pitot tube measurements in the LH2 tank vent duct for the second tanking test for STS-114 (to check for any flow inside the duct, which would indicate leakage). I've heard rumblings of adding various test circuits to the checkout circuit (aka the "SIM circuit") used to test the ECOs during Replenish, but at this point nothing is official.<br /><br />Very very unlikely that we'll do the tanking test with a 24-hour turnaround for a launch attempt. Not impossible, but extremely unlikely. If we do get a go for launch, it'll be a few days afterward, probably next Friday.<br /><br />There was some discussion at MSFC about continuing the last scrub's tanking through to prepress, to see how many prepress cycles we get - but that would add an extra cycle to the ET that we don't want... looks like we'll probably get that anyway, again assuming it happens - and assuming they take it through Terminal Count. Not expecting any prepress anomalies this time... it would just be nice to have the reassurance that we're not going to repeat that...

 

[rocketwatcher2001]

For what it's worth, I'm back in Titusville for the next 4 weeks, at least, so you certainly have my authorization to launch any time, now. <div class="Discussion_UserSignature"> </div>

 

[lunatic133]

LOL!<br /><br />I knew a girl who lives in Orlando, but had to be working during the launch so she hoped it would be delayed until a day she had off. Maybe she'll get her wish...

 

[mah_fl]

I was relieved that the launch did not happen on the 13th.

 

[shuttle_rtf]

Hearing Tanking Test is now Monday, with the launch attempt the follow day.<br /><br />Launch window extended to Aug 4.

 

[emerrill]

"Hearing Tanking Test is now Monday, with the launch attempt the follow day. "<br /><br />So do they just do a 3 day count, down to the 24 hour mark, do a tanking test, then resume the count (putting extra time in there needed for the test, if its not just done in a hold)?<br /><br />"Launch window extended to Aug 4."<br /><br />Is this official (coming from a higher up) or just engineering speculation?<br /><br />Anybody know when the next news conf will be?<br /><br />Thanks<br />-Eric <div class="Discussion_UserSignature"> </div>

 

[emerrill]

"For what it's worth, I'm back in Titusville for the next 4 weeks, " <br /><br />hehe. Yeah, I just got back from titusville/orlando last night. I had been there since the 12th. <br /><br />My wife is saying that she may send me back when they try again (like the 25th-31st), but we'll see, its pretty expensive, and we already spent alot sending me the first time.<br /><br />*curses at the gremlins living the the aft bay* <img src="/images/icons/smile.gif" /><br /><br />-eric <div class="Discussion_UserSignature"> </div>