STS-114 Mission Update Thread (Part 2)

[star_sirius]

Hehehe! Sorry for the misunderstandings, what I meant was the software might trigger the automatic shut downs, perhaps not!! <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>

 

[lunatic133]

Er, I meant I didn't have time to go to Florida in September, not that I didn't have time to hug the bear *hugs the bear again for good measure*

 

[spacefire]

has this sensor failure been discovered after lift-off, would an abort had been initiated? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[shuttle_rtf]

Lunatic, please pass on your contact numbers so I can quote you about causing the launch scrub by lack of RTF Bear hugging <img src="/images/icons/tongue.gif" />

 

[shuttle_rtf]

Sterling job with answering 101 questions on here Dave!<br /><br />Can you update the status of the avionics boxs for the Orbiters...I don't want to misquote or misrepresent previous comments you've made when talking about.<br /><br />When Point Sensor Box is talked about, is that part of the Avionics Box or just another name for Avionics Box?<br /><br />With it being a UA and intermittent, previous talk referred to replacing the box or boards....but that there isn't a spare to replace it with (I believe it was Discovery and Atlantis both have theirs installed, Endeavour is without one right now.)?<br /><br />Just trying to get a grasp on the proceedure for troubleshooting given the previous troubleshooting, as per:<br /><br />This post<br /><br />Or this post<br /><br />Were they simply to troubleshoot ECO sensors 3 and 4? If so, is this going to be the proceedure for ECO sensor 2?<br /><br />Appologies if this is a patchy question at 3:30am in the morning here <img src="/images/icons/smile.gif" /><br /><br />

 

[shuttle_rtf]

Eek, could a mod please parse (I think is the word) my post to reduce the URL length..as I'm messing up the thread dimensions.

 

[shuttle_rtf]

Over Yonder, heh, we'll make a Yorkshireman out of you yet! <img src="/images/icons/smile.gif" /><br /><br />Got four hours in after the press conference...I'm out with the Army looking for terrorist types on a 5am to 11am shift....patrolling this <------ /> stretch of motorway (remember the terrorist cell that did London is from where the "X" is on here...very close to home (I'm York):<br /><br />http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=191&posts=1#M1371<br /><br />Get home, bit more sleep if needed, then back into media mode, do a story about Lunatic's lack of RTF Bear hugging <img src="/images/icons/wink.gif" /> etc.<br /><br />Yep, I look like crap! <img src="/images/icons/smile.gif" />

 

[rogers_buck]

They could have turned that sensor off and relied on a myriad of others. I think thermal cycling the ET for such a trivial problem was (perhaps) not such a good call...

 

[shuttle_rtf]

I think it was Wayne Hale at the conference who said that these ECO sensors are their best/preferred system on monitoring low propellant levels in the ET in order to avoid damaging the SSMEs (paraphrased).

 

[earth_bound_misfit]

Chris, edit your hyperlinks using this code below. Lifted from FAQ's.<br /> title = Makes the given title into a hyperlink pointing to link.<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>

 

[robot_pilot]

>I think it was Wayne Hale at the conference who said that<br /> />these ECO sensors are their best/preferred system on<br /> />monitoring low propellant levels in the ET in order to avoid<br /> />damaging the SSMEs (paraphrased). <br /><br />And that wins the award for the understatement of the century. <img src="/images/icons/wink.gif" /> The ECO sensors are in place to ensure that the SSMEs don't ingest vapor from the tank - if the propellant level runs low too early, the ECOs prevent the SSMEs from draining the tanks completely to the point where the ullage gas is ingested into the engines. If this happens, "cavitation" occurs. Cavitation is, simply put, a VERY bad day. The turbines suddely over-spin (and remember, this is TURBOmachinery we're talking about) because they're expecint a fluid with a much greater density - and they overspin to the point where the turbine blades shatter and tear throough the entire vehicle. It would be a catastrophic loss of life and vehicle.<br /><br />The ECOs aren't armed until near the projected MECO time - I think they are armed when the vehicle reaches a certain velocity (I know that's when MECO is normally commanded) and it takes two of the four ECO sensors to command an SSME shutdown. According to the wording of the ECO-related MPS LCC's, the software bypasses the first "dry" indication but not the second.<br /><br />One other thing I need to add - the ET's LH2 ECO sensor #2 (i.e. the sensor in question today) was working perfectly before the SIM test... and it was apparently working fine after they turned the test OFF (but it was reading WET anyway, so - who knows?) Now, I don't have any idea how they perform this "SIM" test (it's an electronics issue and I deal more with SSME/fluids work) but what they do is send a command through the system that is supposed to return a "DRY" from the ECO sensors being tested. The LH2 #2 ECO did not return a "DRY" but remained wet - indicating a problem someplace. As Shuttle_RTF poste

 

[radarredux]

>> <i><font color="yellow">I need to call my main squeeze who called me on the console but I was too busy to talk..</font>/i><br /><br /> /> <i>Lol, Do you have more than one?</i><br /><br />You know those NASA people and their triple redundancy.</i>

 

[rocketwatcher2001]

It looks like I just might get home in time to see it, after all. Let's hope that this sensor glitch is solved. I'm way too selfish to be disapointed with today's scrub, because I'll be home soon, and home long enough to hear one of my favorite sounds in this world.......*BOOM BOOM*, the sound of an Orbiter returning from space. Landings are just as cool to watch as launches. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> </div>

 

[haywood]

Why is every media outlet in the world continuing to say that the problem was with the LH sensor when SG has already said that the problem was with the LOX Feedline sensor?<br />Where are they getting their information...NASA?<br />Florida today even has a Graphic showing the location of the sensors.<br />Are all these media outlets just incredibly stupid or is NASA passing along the wrong information?<br />I trust SG completely and is disheartening to see that the media still hasn't seen fit to "get with the program"<br />Soledad O'Brian on CNN yesterday even asked a stupid question to an astronaut commentator...<br />"What would happen if they have to roll the shuttle back...cancel the program?"<br />Whew!<br />

 

[nacnud]

Pehaps it’s because of this:<br /><br /><font color="yellow"><br />Allard Beutel /Jessica Rye July 13, 2005<br />Kennedy Space Center, Fla.<br />(Phone: 321/867-2468)<br /><br />RELEASE: 05-183 <br /><b>NASA Reschedules Shuttle Return to Flight</b><br /><br />NASA will attempt to launch the Space Shuttle Return to Flight mission (STS-114) no earlier than 2:40 p.m. EDT, Saturday, July 16. Discovery’s liftoff today from NASA’s Kennedy Space Center, Fla. was postponed at 1:30 p.m. EDT. <br /><br />During countdown activities, a low-level fuel cut-off sensor inside the External Tank (ET) failed a routine pre-launch check. The sensor protects a Shuttle’s main engines by triggering their shut down if fuel runs unexpectedly low. <b><font color="white">The sensor is one of four inside the liquid hydrogen section of the ET</font></b><font color="yellow">. <br /><br />The ET’s liquid oxygen and liquid hydrogen were drained this evening. While the tank was being emptied, engineers monitored and collected data on the <font color="white"><b>failed liquid hydrogen sensor</b><font color="yellow">. They will continue to collect and analyze data overnight. <br /><br />Space Shuttle Program managers plan a series of meetings tomorrow to discuss the problem and determine the steps necessary to get back into the launch countdown. The STS-114 crew will remain at Kennedy while engineers work on the problem. <br /><br />During their 12-day Return to Flight mission to the International Space Station, Discovery’s seven crew members will test new techniques and equipment designed to make Space Shuttles safer. They’ll also deliver supplies and make repairs to the Space Station. <br /><br />For the latest information about the STS-114 mission, visit: <br /><br /><font color="white">There is defiantly some confusion somewhere.<br /></font></font></font></font></font>

 

[shuttle_rtf]

>Why is every media outlet in the world continuing to say that the problem was with the LH sensor when SG has already said that the problem was with the LOX Feedline sensor? <<br /><br />LOX Feedline sensor? - Can you copy where SG said that, I missed it.<br /><br />I've got LH2 ECO (Number 2 sensor) as the basic problem, although I'm working through the whole process and immediate troubleshooting that occured...so there's more to come.

 

[nacnud]

RTF here you go:<br /><br /><font color="orange">HeneryHallam: "I'm a little confused - which of the sensors failed today, and which failed during the tanking tests? Did both LH2 and LOX sensors fail today? " <br /><br /><font color="yellow">Shuttle_Guy: “No just Lox sensor 2”<br /><br /><font color="white">Also<br /><br /><font color="orange">Tap_Sa:"hoping that the bug didn't show up during countdown. If that is NASA way of business as usual then " <br /><br /><font color="yellow">Shuttle_Guy:”Actually the previous problem weth fuel sensors 3 and 4 did not show up again !!! This was a Lox sensor # 2!”<br /><br />Link<br /></font></font></font></font></font>

 

[holmec]

I hope the weather holds up. I think there is another tropical storm brewing. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[peter_vankman]

Shuttle_Guy was incorrect. It was in LH2 sensor #2. He was probably typing pretty fast. I work in MCC and got the goods straight from the BOOSTER officer.

 

[tap_sa]

Hmm, I even asked S_G to confirm it was the LOX:<br /><br /><font color="yellow">"Btw are you positive about the LOX sensor, everybody up till now including www.nasa.gov speaks of fuel sensor. "<br /><br />Yes I am. NASA has reverted to the generic term for ET Lox and hydrogen loading as "fueling" because of the misuse of the term.<br /><br />I was there. I saw the data.</font> <br /><br />edit: How much difference there is between LOX and LH2 sensors, is one considerably easier to inspect/change/fix than the other?

 

[nacnud]

I know very little about the STS but from the posts on this thread:<br /><br />The LOX sensors are in the LOX tank section near the top of the ET.<br />The LH2 sensors are in the LH2 feed line, presumably between the OV and the ET.<br /><br />However, the sensors are just resistors that change temperature, and therefore resistance, when no longer exposed to cryogenic liquid. I doubt the problem is in the sensor itself.

 

[lunatic133]

Besides, isn't an RTLS abort more risky than just flying with bad sensors? and an AOA or the like would be rather pointless since the problem is with the ET Good thing they caught it when they did I suppose.

 

[shuttle_rtf]

>The Point Sensor box is a separate box which is located inside a aft fuselage avionics bay. <<br /><br />Thanks SG.

 

[lunatic133]

I'm just confused because from what I've read, the sensors are located on the ET. Once the shuttle has reached orbit and the ET is released, then so are the sensors, right? So why do they still need to abort?<br /><br />I guess I'm not exactly a rocket scientist ... yet <img src="/images/icons/wink.gif" />

 

[tap_sa]

<font color="yellow">"ECO sensors can not shut the engines down and cause a RTLS abort because they are not armed until <b>8 seconds</b> before the predicted normal engine cut off."</font><br /><br />That's quite a small timewindow compared to the total burn time. What happens if engines run dry before that 8 seconds, does some other system detect that and do cut off?