Space Shuttle Return to Flight - Pt. 2

[najab]

You can look at it that way, but you could also look at it from the perspective that they aren't <b>flying</b> an unsafe vehicle. It can be as unsafe as it wants to be, as long as it's not going anywhere - when game day comes it will be safe (well as safe as Shuttle ever can be), even if they have to postpone game day to make it so.

 

[shuttle_rtf]

Ooo, this image updates every 30 seconds. Cool, source NASA TV...The picture on here is 'from a saved file' as that's how it works here. So I've set up a live (refresh for new image) thread here:<br /><br />http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=79&posts=1#M649

 

[vogon13]

Foreshadowing concerns gripped me.<br /><br />Perhaps I am more anxious about RTF than most. How many successful flights till I chill?<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[shuttle_rtf]

The liquid hydrogen vent valve cycled 13 times again on Tanking Test 2.<br /><br />Again this is twice as many as normal.<br /><br />No word on the ECOs

 

[shuttle_rtf]

Just copying and pasting this across from the NASA Space Flight site...<br /><br />Here's what happened with ET-121 from a USA guy in attendance:<br /><br />"Before ET sling was hooked up to lift it out of checkout cell, one of the connecting drop links 'bumped' into tank foam - in the intertank area - due to a crane move that no one was ready for..i.e. the lanyards that individuals hold to secure movement of 'loose' equipment (including sling cables, links etc.) was not manned. Crane made the move and cable/link moved from it's hanging position and gently swung/bumped the foam. Determined not to be an issue but, we'll see if it elevates. Made a mark!"

 

[redgryphon]

<font color="yellow">The abnormal LH2 pre pressurization did happen again. However we were able to eliminate a leaky vent valve as the possible cause. The data analysis will take a week or more. </font><br /><br />Does that mean a third test (on ET-121) is more likely?

 

[najab]

Hey, shuttle_guy, I hope you aren't getting too bummed out by the delays. Remember, you guys have to launch 18 flights in 4 1/2 years, so it will pay off to take a little time make the vehicle as perfect as possible.<br /><br />That's about the perfect flight rate - 4 to 5 flights a year - enough to keep you busy, but not so many as to have you under schedule pressure.

 

[redgryphon]

Thanks sg. I'm beginning to get nervous about the July window now. Harwood suggested that another test may push the launch date to July 19, unless the test is put into some kind of extended countdown. (That option seems odd to me. It could put a lot of pressure on engineers to complete the analysis while the count was in progress.)<br /><br />Are you still feeling 80:20 about a July launch?

 

[shuttle_rtf]

Thanks SG - hope you're getting some rest inbetween all of this.

 

[shuttle_rtf]

Parsons and Hale said the same thing on the last test - i.e. they don't tend to mention problems.

 

[shuttle_rtf]

Yep

 

[Testing]

What the heck is wrong with that # 2 engine chip detector, It's always giving a false master caution........... <div class="Discussion_UserSignature"> </div>

 

[shuttle_rtf]

Feeling better, SG?<br /><br />Is it safe to say the ECO issue is still an UA - given it looks like, but isn't certain, that the issue may have been fixed....also assuming the review of the Tanking Test may shed some more light on this.<br /><br />The second thing is the Ice build-up concerns were noted after Tanking Test one....was there any mention of ice build up on Tanking Test two - I didn't see anything by way of comment from the team that inspected the ET on Tanking Test two.<br /><br />Again, might be info that needs to come from the review that you mentioned will take about a week.

 

[got_mmh]

You need to differentiate between Ice and Frost. Ice density and frost density are obviously drastically different.<br /><br />The first tanking test had acceptable FROST on the LO2 feedline bellows per the 8303 Launch Commit Criteria (LCC) and we could have launched that day without concern for damaging the orbiter. The newly designed drip lip performed as advertised. However NASA had just received some new data on low density ICE (slush) could be as damaging to RCC as solid ice. <br /><br />I don't know what your access is to information but there was plenty of discussion of the performance of the bellows ice/frost. It performed exactly the same with frost buildup within the LCC and again we could have launched. Even though it was more humid and the rate of condensation was higher that the first test.<br /><br />Info might take a week to disseminate but everyone in the Final Inspection Team circle knows exactly what the conditions were and that they were acceptable per 8303. However Griffin has asked us to put the heaters on and Astronauts don't want to fly with frost OR ice in the debris zone.<br />

 

[shuttle_rtf]

Very interesting.<br /><br /> />However NASA had just received some new data on low density ICE (slush) could be as damaging to RCC as solid ice. <<br /><br />Did the DVR come up with that? I'm guessing, but are the heaters designed to stop ice forming - and I'm just talking about ice at the moment as frost is something I'm going to have to read up on - or, do the heaters tackle formed ice, thus making it into slush?<br /><br />You see where I'm going here.

 

[ozspace]

Florida Today and Spaceflight Now are saying the roll back to the VAB will be delayed until Friday so they can check Discovery's landing gear for cracks....they found some on Atlantis. So, inspection with borescope at the pad today, then APU firing Wednesday then into the shed Friday. There goes some more padding time...

 

[shuttle_rtf]

Oh crap <img src="/images/icons/frown.gif" />

 

[najab]

Surely though, this was checked during the last OMM?

 

[najab]

How long is the stack swap likely to take? Obviously it's not a one-day job.<p>And you didn't happen to have found out yet if it's been done before?</p>

 

[rocketwatcher2001]

O.K., what did I miss? Why are we swapping out ET's? I thought it passed Friday's test. I'm sure that this has been brought up before, but I havn't been online much recently. <div class="Discussion_UserSignature"> </div>

 

[henryhallam]

I think the idea is that it is still an Unexplained Anomaly - even though the problem didn't show up on the second tanking test, that doesn't guarantee it's been fixed (although it seems very likely that it has been fixed by changing some of the equipment in the Orbiter). So to really be sure it won't be a problem, they will swap tanks and then everything that could affect the ECO sensors including the sensors themselves will have been changed.<br /><br />There is also still the separate issue with the hydrogen vent valve cycling, but the valve itself is not believed to be the cause of that problem.

 

[rocketwatcher2001]

So I guess they don't sign off the log-book as, "Performed inspection of wiring, re-racked terminals, OPS check good." <div class="Discussion_UserSignature"> </div>

 

[SpaceKiwi]

<blockquote><font class="small">In reply to:</font><hr /><p>O.K., what did I miss? Why are we swapping out ET's? I thought it passed Friday's test. I'm sure that this has been brought up before, but I havn't been online much recently.<p><hr /></p></p></blockquote><br /><br />An additional secondary issue with the ET change is the LOX feedline bellows heater mod. Although they could fit the heater to Discovery's current ET, I think it's worked out better to mod the one in the VAB while there isn't an Orbiter strapped to the side.<br /><br />In answer to new's question, I get the impression Discovery's current ET is going back to Michoud for disassembly, so I don't think they are interested in fitting the LOX feedline bellows heater to that one. I assume it will get one over there when that ET is rebuilt for a future mission. <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>

 

[SpaceKiwi]

<blockquote><font class="small">In reply to:</font><hr /><p>Well not disassembled. It will go back to Michoud to Test and replace the ET side of the ECO sensors in the LH2 tank, Change the lOX and Hydrogen diffusers, and install the heater mod.<p><hr /></p></p></blockquote><br /><br />Yes, I probably got a little 'enthusiastic' with my comment. They will strip the foam off though, do you think? With the work to be done, and the heightened sensitivity to foam shedding, I imagine a fresh re-spray from scratch might be the order of the day? <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>

 

[got_mmh]

No, ET-120 will get heater modification and replace GH2 diffuser in the VAB now that ECO sensor issue has been resolved. Likely written off as UA since orbiter changed their black box and found the recessed pins in their connectors. Likely fly STS-121 mission. Since Michoud people are working at KSC that means they are not working on ET-119 in New Orleans and we need a rescue shuttle stack close to ready to launch the first one.