STS-114 Mission Update Thread (Part 2)

[ltm_se]

I'm rather a newbie here at the forum. When I visited KSC a few years ago and i was amazed at the complexity of the shuttle. Now after I have spent the last weeks constantly following the threads about the RTF, I have to say that you SG, have my deepest respect. You seam to know just about everything there is to know about one of the most complex system in the world, the shuttle program. U rule!<br /><br />Thank you!<br />

 

[star_sirius]

That's awesome, can't wait, thanks for providing first- hand info. <div class="Discussion_UserSignature"> <font size="0" color="#10bdee"><strong>A dazzling bluish luminosity from A distant south pacific.</strong></font><p><br /><img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /></p> </div>

 

[shuttle_rtf]

>Some good news from the launch attempt.<br /><br />The Main Propulsion engineers were able to tell from the ET loading data that the LH2 and LOX diffusers worked properly even though we did not take the tank to flight pressure with it fully loaded.<br /><br />The pre-press large number of cycles during the first and second tanking tests has been fixed.<<br /><br />Sounds like (tell me what you think SG) that the new diffuser on Tanking Test 1 and 2 (Double Weave design - ET-120) was to blame - given the old style Single Weave in the current ET-(ET-121) isn't over-cycling?

 

[lunatio_gordin]

Uh oh. On my home page i just saw "launch postponed indefinitely". is that so? doesn't look like we're getting this window...

 

[dougbaker]

I found an intersting document<br />http://www.jsc.nasa.gov/news/columbia/nsts08399/book00/part4/031042703.pdf

 

[shuttle_rtf]

What site? I know we had a JSC guy post that very phrase on the forum, but he meant as you've read above - just means there's no solid date yet. As far as the news page (and it'll be me writing it), I'm going with the "troubleshoot - then four days to get everything prepped for launch" - just waiting for some quotes on how the troubleshooting is looking before running it (rather than repeating what other sites have gone with from the conference).

 

[shuttle_rtf]

JOHN SCHWARTZ of the NY Times is claiming Wayne Hale has said that if the troubleshooting doesn't work, they will go for a launch anyway.<br /><br />I didn't believe that until I saw the wire update (no full story yet)...<br /><br />"Shuttle Launching May Proceed Without Sensor Solution<br />New York Times - New York,NY,USA"<br /><br />Comments? Would this be in hope of the lack of an ECO sensor issue on Tanking Test 2? All Four (or eight - four LOX, four LH2) HAVE to be working, right?

 

[scottb50]

If they isolate the problem to one sensor that still leaves two working. Where do you raw the line? There are so many things that have to work perfectly and eventually it gets to a point where both SRB's have to work and at least two SSME's have to work. <br /><br />That's the problem with Shuttle, if all else fails your doomed, there is no escape system that would work in every phase or even a few phases of flight. Odds are with the number of safe launches under it's belt another has a very high degree of probability of succeeding. <div class="Discussion_UserSignature"> </div>

 

[shuttle_rtf]

Personally, I think the reporter is stretching comments from Hale - after listening through the press conference. I do not see how Hale has said that they are seriously considering launching with a lower launch commitment than the four sensors (or eight, depends how you look it it). It could be possible that they could see if it simply is a freak thing (but they are going to have to do the process again anyway to see if they did fix it - as they thought last time).<br /><br />I simply think the reporter has gone for a fresh header to the other media, which happens (although it's wrong). NY Times though!

 

[tap_sa]

<font color="yellow">""Shuttle Launching May Proceed Without Sensor Solution<br />New York Times - New York,NY,USA"<br /><br />Comments? "</font><br /><br />Well, what else can they do? Especially if the sensor problems stays as a unexplained anomaly. IIRC it wasn't actually Hale but the other guy next to him that said in the last news conference that there's been lot of discussion whether just go with three good sensors or not, and sort of gave the impression that it is becoming more real option. <br /><br />All four don't <i>have</i> to work, two is enough. IMO the shuttle is getting so old that the NASA has to utilize the redundancy already on the launch pad instead of just some extremely unlikely in-flight events.<br /> <br />edit: Question, does the grain in SRBs and amount the of propellant in ET vary based on mission parameters (amount of cargo in orbiter payload comes to mind) ? If it does and especially ET has more ullage when payload is light then how about just filling it as full as possible to add more safety margin, AFAIK the cargo in this flight isn't very heavy.

 

[ltm_se]

How do you test the different systems. If one sensor displays faulty readings and you are not sure if it is the sensor or the box, couldn't you just switch wires between sensor 1 and 2 and see if the error traverses to the other sensor?

 

[tap_sa]

<font color="yellow">"Not if one is failed dry. "</font><br /><br />I said two <i>working</i> sensors is enough, meaning it's enough to properly send the two needed dry signals for the software to do MECO. Of course it (nor 3 or 3000 working sensors) doesn't guarantee erraneous premature action if some two other sensors fail and start to give faulty dry signal. AFAIK it's far less serious to mistakingly do the low level cut off than fail to do it when needed.

 

[haywood]

Good point Itm_Se.<br /><br />SG, is that one of the items in the Fault Tree?<br />It seems as is if that would be one of the first obvious things to try and I'm sure that would have been tried.<br /><br />This must be really frustrating to all the engineers and technicians looking at the problem.<br /><br />You would assume that if A=B and B=C, then A=C. But things are not always that simple. Especially if there is some "X" factor hiding somewhere.<br /><br />Like Itm_Se mentioned, is there some way to "switch" connections between sensors and sensor box connectors to validate where the problem is? If so, that might be a way to test the source of the problems.<br /><br />Imagine, here we are, amateurs trying to give insight to all the technical expertise at NASA. That would be a first.<br /><br />I have no doubt you'll find the problem without our help.<br />

 

[planet_z]

AP-Space Shuttle: Fatigue<br /><br />Shuttle delay brings a much-needed break for launch controllers<br /><br /> KENNEDY SPACE CENTER (AP) - Part of what's driving NASA managers<br />to take a break from the Discovery countdown is firing room<br />fatigue.<br /> Engineers need more time to troubleshoot the shuttle's problems.<br />And the astronauts would like to be home in Houston if they're not<br />needed at the Cape.<br /> But NASA spokesman Bruce Buckingham points out the people who've<br />been on edge at launch control all week are a very focused and<br />intense bunch who could use a long weekend. He says they're<br />"people who need sleep, people who need sustenance" -- people who<br />can't even eat or drink at their consoles during their eight-hour<br />shifts.<br /> Space agency managers have decided the earliest they can attempt<br />another launch is late next week. They hope to announce a target<br />date later today.<br /><br /> (Copyright 2005 by The Associated Press. All Rights Reserved.)<br /> <br />AP-NY-07-16-05 0640EDT

 

[tap_sa]

<font color="yellow">"A late flight software change is not an easy thing to do."</font><br /><br />What, you mean it doesn't go just like this?? <img src="/images/icons/wink.gif" /><br /><br />Collins: Discovery, ignore fuel ECO sensor #2 actual reading and assume it always reads wet.<br /><br />Discovery (robotic voice): Affirmative.<br /><br /><br />I thought the sensor in question read wet and kept reading wet inspite test command to force it read dry? A sensor stuck wet is ignored without change to the software ... unless of course it starts to act more during the flight, flipping on and off or something.<br /><br /><br />Can you tell us what's happening on the pad? Are there personel working on the orbiter, probing the wires etc actual troubleshooting?<br />

 

[haywood]

As a layman, I find these exchanges to be fascinating... and productive.<br />Never before has the general public been able to interract so intimately with the nation's space program.<br />And the credit has to go to those people like shuttle_guy who realize the passion still existing for the space program...and the new-found openness within NASA and the technology that makes this all possible.<br />My hat's off to all involved.<br />

 

[lunatio_gordin]

CAPE CANAVERAL, Fla.(AP) NASA's first shuttle flight in more than two years has been put off indefinitely as the space agency mounts a massive investigation into why a fuel gauge failed right before Discovery's scheduled liftoff.<br /><br />Engineers were no closer Friday to knowing why the gauge acted up two days earlier.<br /><br />"We are going forward on a day-by-day basis," said deputy shuttle program manager Wayne Hale. "We have got the entire resources of the agency behind us to troubleshoot this problem."<br /><br />Hale said that once the problem was identified and fixed, it would be another four days before the shuttle could launch.<br /><br />"Everybody is going to want to ask, 'What is that date going to be?' Well, I don't know," he said.<br /><br />It was the latest setback in NASA's grueling and drawn-out quest to return to space and recover from the 2003 Columbia tragedy. The space agency has made a multitude of safety improvements to the aging shuttle to avoid future catastrophes, efforts that have repeatedly delayed Discovery's mission.<br /><br />Engineers are looking at whether any of those safety improvements _ like additional heaters on the external fuel tank to prevent dangerous ice buildup _ may be contributing to the failure of one of the four fuel gauges in the tank. When the gauge showed an improper setting, Wednesday's launch was canceled.<br /><br />Hale said it's possible NASA could try to launch again late next week, "but that would require a very near-term lucky find" of the source of the problem.<br /><br />Discovery's seven astronauts opted to remain in Cape Canaveral and wait it out, rather than return to their homes in Houston.<br />Managers had held out hope, however slim, that they might be able to launch Discovery within a few days. But with engineers no closer to figuring out why the fuel sensor malfunctioned Wednesday _ a potentially deadly problem _ NASA had no choice but to call for a lengthy standdown.<br /><br />NASA is up against the clock.

 

[shuttle_rtf]

There was nothing to correct on the diffuser. It was a different (old style) diffuser and a different ET (ET-121)<br /><br />The new diffuser on ET-120 wasn't corrected, it didn't work properly, period.

 

[tap_sa]

Shuttle_guy, 1207's analysis about the unfortunate timing of the test and the PR guy are exactly the things I meant the other day in the poorly worded moronic-post. I guess you mistook it as a critic aimed at you and your collegues who are doing the actual work but nothing could be further from the truth. I may not be the biggest fan of the shuttle but I (and surely all the other STS critics) have the upmost respect to you and all the other who actually make the shuttle happen. It's the management that gets my blame. The 'silly' design requirement and politics (Thiokol Utah etc), ignorance to prevent Challenger and Columbia despite warnings from engineers, and now they are ruining your credibility in the public eye because the PR guy didn't realize that the RTF isn't just another launch but really is under the world microscope.<br /><br />So my hat is flying high too for you personally for taking the time to educate us amateurs, to everyone who is or has been involved in the not so little miracle of creating the STS to meet the nearly impossible requirements with limited budget, and keeping it flying after almost three times the estimated lifespan. I just fear that there is so much so complex and <i>old</i> electronics that it's starting to fall apart faster than even best of the best can fix. In this situation Hale & co can no longer scrub things because absolutely everything isn't in 100% condition. That's why the redundancy is there for. It seems like the press is feeling the same and it's getting restless. Some of the questions in news conferences are getting quite ugly.

 

[shuttle_rtf]

>-The diffuser was corrected and worked fine Wednesday. <<br /><br />I was responding to that and I'm know Newsartist is aware. It was a clarification post - given the above is not the case - so we don't have other people thinking there was anything wrong with ET-121's diffuser, seen as there wasn't. <br /><br />Absolutely no 'correcting' going on here with me, I'm simply not qualified to do so..just adding to the mix <img src="/images/icons/smile.gif" />

 

[Leovinus]

One question I'd like asked at one of these press conferences would be:<br /><br />"If this were a rescue mission, would you fly with 3/4 working sensors?" <div class="Discussion_UserSignature"> </div>

 

[shuttle_rtf]

A great question that I also would love to ask.

 

[shuttle_rtf]

Interesting post.<br /><br /> />So they labeled the problem an unexplained anomaly and switched tanks. The new tank as I recall had a new heater. <<br /><br />My memory is a bit loose at this time in the morning - and I'm simply panning this out to add to your post - but I believe the main reason for the ET switch was relating to the feedline heater *with it being installed on ET-121 in the VAB by Michoud engineers, ready for mating with Discovery and then rolled out again.*<br /><br />I don't think they made a big thing about the pre-press over-cycling or the ECOs (given the ECOs were fine on Tanking Test 2) on the rollback and ET swap.<br /><br />It is worth noting at the time of the new difusser issue, SG noted the MSFC element..............and was duly justified, given the usual style diffuser seems fine.

 

[shuttle_rtf]

>unexplained anomaly<<br /><br />Yeah, that's actually an official term, it seems!<br /><br /> />By the way, were they just testing to monitor ice build up? Initially at least.<<br /><br />On the Tanking Tests? If so, not specifically.

 

[shuttle_rtf]

Why did they do what? (Sorry mate, I'm trying to understand what you're getting at) <img src="/images/icons/smile.gif" />