Space Shuttle Return to Flight - Pt. 2

[got_mmh]

The area of foam to be removed is small and will be reapplied. This sort of faom repair happens all the time. Like when you scratch your car, you only repair a small area, not repaint the whole thing.

 

[got_mmh]

We are switching ET's because Mike Griffen, the new NASA director, asked us to put heaters on the LO2 feedline bellows. We started work on that modification on ET-121 in the VAB 3 weeks ago while doing troubleshooting on ECO sensors at the pad. We didn't want to unhook everything at the pad becuase then we couldn't troubleshoot the entire system. <br /> <br />By the time the shuttle rolls back the heater mod will be near complete and will take less time to just swap stacks than to complete the heater mod and diffuser changeout on the current ET (ET-120).<br /> <br />When the next orbiter is ready, all tank mod's will be complete and can just mate it to the current ET/booster stack.

 

[earth_bound_misfit]

got_mmh, thanks for all the "good oil"<br /><br />Sorry if this next question is personal, but I was wondering what your nickname stands for? I can't think of anything, and maybe others might also be wondering.<br /> <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>

 

[redgryphon]

My guess is mmh stands for monomethylhydrazine, a liquid propellant usually used in upper stages.

 

[shuttle_rtf]

Has there been any movement to clarification on whether a third tanking test is required?<br /><br />The interest is based around the potential launch window in July.<br /><br />No further tanking test - still looking possible to make the July 13th start of window. Third tanking test required - more like 18th?

 

[shuttle_rtf]

Thanks.

 

[got_mmh]

Okay, now this is informed conjecture on my part.<br /><br />Now that they have excluded the bipod heaters as not the culprit for the extra cycling during pre-press and deciding that the LH2 diffuser is the next item to be considered, they will likely do another tanking test with ET-121 since it has the old diffuser installed in the VAB. This will tell them if it was a diffuser or if they have another cause for the 5 extra cylces for pre-press. <br /><br />The extra cylces aren't really cause for concern, except that it has always been less. When engineers in manned space flight see different, that is equal to BAD.<br /><br />If this was an EELV launch they probably wouldn't have given it a second thought. I could be wrong.

 

[got_mmh]

"....I imagine a fresh re-spray from scratch might be the order of the day? " <br /><br />But it has not been resolved since no definite cause was found. As you say it will probably be a UA. <br /><br />It appears that you have better information than I do. I guess I mis understood or got bad data about it going back to the plant. That did seem to be a bit extreme. "<br />_____________________________________________<br /><br />The ECO sensors themselves were thrown out as the source of the problems and Lockheed Martin electrical design engineers said DEFINATIVELY that the sensors themsleves could not have caused the problems they were having. <br /><br />This was a connection issue so the sensors could be aquitted, however every other foot of wiring and every connector in the loop was suspect. We know that the Orbiter had a modified cable and black box (read:"untested configuration"). If we had a repeat of the dry/wet ECO sensor then both the orbiter AND ET would have basically had to have all the wiring in the loop replaced or verified. THEN the ET would have went to Michoud to have it torn apart (the orbiter wouldn't have flown this mission either, I suspect).<br /><br />There were plenty of self-proclaimed "experts" at KSC saying we needed to send the ET back (none of these people were Elec. Engineers or knowledgable of the system).<br /><br />If any of you own american cars and had electrical problems, you take it to the dealer and they start throwing parts at it until the problem goes away, and they can never say what the problem was....this is the nature of the beast with funky electrical issues. Except the Shuttle/launch pad/launch control center has hundreds of miles of wiring.<br /><br />

 

[got_mmh]

I want you all to understand that there are very few people at KSC who have all the pieces of the puzzle when it comes to information, mostly guys in the NASA Test Director Office. A lot of people have no pieces and make grand statements based on rumor and eavesdropping.<br /><br />Any statement I make that I don't know for fact I will qualify as conjecture. Everything else you can more or less take to the bank, or is limited by my own understanding. I have seen other posts here that are 80% correct but obviously not based on 1st hand knowledge. Please take everything said here, and in the press with a grain of salt. The press largely cannot get their hands around most of the technical issues and I find they are rarely correct about TECHNICAL things they report on or they miss something key.<br /><br />The processing and launching of the Shuttle is like playing 45 boards of chess simultaneously. The technology is not that new but EXTREMELY complex to integrate everything on schedule. People who have been here 20 years still only know a portion of what is required.<br /><br />For example, an Orbiter Fuel Cell guy knows everything there is to know about his system and can speak intelligently about main propulsion but only just. They will know NOTHING about SRB's or ET. We are all very specialized, while we know more than the press, we still are uninformed on a lot.<br /><br />Yes MMH is monomethylhydrazine, the fuel component of hypergolic fuel (nitrogen tetroxide, N204, is the other component), i.e. “got rocket fuel”<br />

 

[ozspace]

"Please take everything said here, and in the press with a grain of salt."<br /><br />I hope this is true..........Spaceflight Now are reporting that the inspections on Discovery are complete and no cracks found.<br />http://www.spaceflightnow.com/shuttle/sts114/status.html

 

[shuttle_rtf]

Yes, it was just Atlantis. Discovery and Endeavour don't have the same issue - noting information from the Florida media, although Justin has some nice quotes to add to the mix there .

 

[shuttle_rtf]

>Yes MMH is monomethylhydrazine, the fuel component of hypergolic fuel (nitrogen tetroxide, N204, is the other component), i.e. “got rocket fuel”<<br /><br />Although I'm sure the advise would be to not to try out a monomethylhydrazine moustache....unless you wish to kiss your skin goodbye.<br /><br />Milk = Ok<br />Monomethylhydrazine = Ok only if you are a RCS <img src="/images/icons/wink.gif" />

 

[got_mmh]

LOL<br /><br />Well, then you'll understand my disfigured face and the minor twitch

 

[shuttle_rtf]

I feel a Monty Phython sketch coming on. Right after I've checked out the KSC on-line store for some Monomethylhydrazine Moonshine! <img src="/images/icons/smile.gif" /> "Your own BRFC in a bottle"

 

[ozspace]

Looks like the RSS is being rolled back for today's APU test...<br /><br />http://science.ksc.nasa.gov/shuttle/countdown/video/chan3large.jpg

 

[shuttle_rtf]

And to be clear. The media say the test is on "one APU" but SG says it's on all three?

 

[henryhallam]

<font color="yellow"><br />The extra cycles show that the pre-press system is having difficulty maintaining flight ullage pressure. This is when the ullage is small. This could meand the same sysmem in flight woulk not be able to maintain the LH2 ullage pressure and the result would mean the loss of the vehicle.<br /></font><br /><br />Ouch! Do you have any educated guesses as to what might be causing the problem?

 

[franson_space]

Why is it one person says they are fine and the other says it could result in the loss of a Shuttle. That's a real concern and sounds just like the stop/go confusion that saw the loss of the Columbia and more so the Challenger. When will everyone get on the same page!

 

[najab]

As got_mmh said, the 'confusion' comes about because people are experts in their own area, and don't necessarily know what's happening in another one.<br /><br />Plus, there's a difference between what <i>could</i> happen, and what's <i>likely</i> to happen. got_mmh was talking about what was the most likely outcome, shuttle_guy was describing the worst case.

 

[najab]

><i>...that comment was a little strange to me as well...</i><p>You mean me? I can be strange at times, I know, but I thought what I was trying to say was clear.</p>

 

[shuttle_rtf]

Seen as it doesn't work on this forum's format, I've set up a live image thread on the NSF site - refresh the page every 30 seconds for another live image of the roll-back.<br /><br />http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=83&posts=1#M682

 

[earth_bound_misfit]

Monomethylhydrazine, sounds like something that you wouldn’t want to start siphoning by mouth. Ever had a mouthful of gasoline? <img src="/images/icons/wink.gif" /> <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>

 

[shuttle_rtf]

I've had a mouthful of petrol after using the suck-the-end-of-a-pipe to empty a tank experience. <br /><br />Was rather tangy! And rather expensive, given we're at about 12 bucks a gallon here.

 

[shuttle_rtf]

No sign of movement yet. The Crawler is there, but we're 80 mins past the 2am EST and no movement yet.

 

[shuttle_rtf]

4:30am EST and still on the pad. Justin Ray with SpaceFlightNow - and at KSC - just updated with a line saying "The rollback has not yet started."<br /><br />Might as well get some shut-eye for a few hours.