{"id":41496,"date":"2008-01-25T21:47:56","date_gmt":"2008-01-25T13:47:56","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/root-cause-confirmed-as-sts-122-marches-towards-launch\/"},"modified":"2008-01-25T21:47:56","modified_gmt":"2008-01-25T13:47:56","slug":"root-cause-confirmed-as-sts-122-marches-towards-launch","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/root-cause-confirmed-as-sts-122-marches-towards-launch\/","title":{"rendered":"Root cause confirmed as STS-122 marches towards launch"},"content":{"rendered":"<p>ECO (Engine Cut Off) sensor anomalies are caused by \u201csubstantial amount of Krytox grease and silicon contamination\u201d on the External LH2 Feed-through connector plug and pins, testing has found, as STS-122 marches \u2013 with confidence \u2013 towards launch next month.\n<\/p>\n<p>  A major discussion on the LCC (Launch Commit Criteria) has also been conducted, ahead of approval by the Flight Readiness Review (FRR), that will allow for slight sensor issues during the countdown.\n<\/p>\n<p><em><img fetchpriority=\"high\" decoding=\"async\" height=\"129\" alt=\"\" hspace=\"5\" src=\"http:\/\/forum.nasaspaceflight.com\/forums\/get-attachment.asp?action=view&amp;attachmentid=13910\" width=\"600\" align=\"left\" vspace=\"5\" border=\"0\/\"><\/em><\/p>\n<p><em>**The most comprehensive collection&nbsp;of&nbsp;Shuttle, Ares, Orion&nbsp;and ISS&nbsp;related presentations and mission documentation, plus expansive daily processing documentation and updates&nbsp;are&nbsp;<\/em><font color=\"#0000ff\"><em>available to download&nbsp;on L2<\/em><\/font><font color=\"#0000ff\"><em>&nbsp;**<\/em><\/font><\/p>\n<p><font color=\"#ff0000\"><em><img loading=\"lazy\" decoding=\"async\" height=\"139\" alt=\"\" hspace=\"5\" src=\"http:\/\/forum.nasaspaceflight.com\/forums\/get-attachment.asp?action=view&amp;attachmentid=31173\" width=\"212\" align=\"left\" vspace=\"5\" border=\"0\/\"><\/em><\/font><font color=\"#ff0000\"><em>STS-122 L2 Special NOW LIVE.&nbsp;<\/em><\/font><em><font color=\"#0033ff\">**Click&nbsp;here for sample of L2 menu and content**<\/font><\/em><\/p>\n<p><font color=\"#ff0000\" size=\"3\"><\/font><font size=\"2\"><em>**STS-122 Special:&nbsp;29 Flight Readiness Review (FRR) Presentations, Baselines and Mission Overviews. <font color=\"#0000ff\">**Click here for FRR&nbsp;overview articles: <\/font><\/em><font color=\"#0000ff\"><em>Article 1<\/em><\/font><\/font><font color=\"#0000ff\"><em> \u2013 <\/em><\/font><font color=\"#0000ff\"><em>Article 2<\/em><\/font><font color=\"#000000\"><\/font><font color=\"#0000ff\"><em>**<\/em><\/font>&nbsp;<em>Payload Presentations and vast amounts of live, uploaded images and presentations, movies (several)&nbsp;\u2013 already&nbsp;2600&nbsp;megabytes strong** <\/em><\/p>\n<p>**COMPLETE Section \u2013 over 1300mbs of presentations \u2013 on ECO\/Feedthrough Connector issues and troubleshooting, graphical and data based \u2013 expansive.**<\/p>\n<p><font color=\"#0000ff\" size=\"3\"><em>**LIVE updates on Atlantis&nbsp;STS-122 Troubleshooting Latest**<\/em><\/font><\/p>\n<p><font color=\"#0000ff\"><em>**LIVE updates on Discovery STS-124 Processing**<\/em><\/font><\/p>\n<p><em><u><\/u><\/em><\/p>\n<\/p>\n<p>Technology News<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>NASA educational resources<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>Rocket launch schedules<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>\n<p>     (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n<\/p>\n<p>&nbsp;<em><font color=\"#0000ff\">**LIVE news updates on&nbsp;Endeavour&nbsp;STS-123 Processing**<\/font><\/em><\/p>\n<p>STS-122 ECO related news content: *Scrub 1* \u2013&nbsp;*MMT Debate*&nbsp;\u2013 *Scrub 2*&nbsp;\u2013 *Hale Memo*&nbsp;\u2013 *Forward Plan*&nbsp;\u2013 *Culprit Found*&nbsp;\u2013 *Tanking Test*&nbsp;\u2013 *Repair&nbsp;Options*&nbsp;\u2013 *MAF Plan* \u2013 *PRCB Debate*&nbsp;\u2013 *Plan Approved*&nbsp;\u2013 *Repair Schedule*&nbsp;\u2013 *Launch Date*&nbsp;\u2013 *New Issue*&nbsp;\u2013 *Hale Rallying Call*&nbsp;\u2013 *PRCB Launch Dates*&nbsp;\u2013 *New Connector Installed*&nbsp;\u2013 *Positive Test Results*&nbsp;\u2013 *Manifest Impacts*&nbsp;\u2013 *Optimism&nbsp;with forward plan*&nbsp;\u2013&nbsp;*Flight Rationale*&nbsp;\u2013 *Repairs Finalizing*<\/p>\n<p><em><u>STS-122 Troubleshooting Latest: (Pre-FRR) \u2013&nbsp;FRR Presentations (Jan 25) available to download in&nbsp;L2).<\/u><\/em><\/p>\n<p>Thursday\u2019s Program Requirements Control Board (PRCB) meeting was presented with a complete run down of the test results, showing the issue of contamination was deemed responsible for the issues during the two launch attempts and subsequent tanking test. <\/p>\n<p><img loading=\"lazy\" decoding=\"async\" height=\"153\" alt=\"\" hspace=\"5\" src=\"http:\/\/forum.nasaspaceflight.com\/forums\/get-attachment.asp?action=view&amp;attachmentid=38988\" width=\"199\" align=\"left\" vspace=\"5\" border=\"0\/\">\u2018Substantial amount of Krytox grease and silicon contamination present in ET-125 external feed through,\u2019 noted a PRCB overview presentation. \u2018Krytox grease and has been proved to be an electrical insulator at cryogenic (-90 F) temperatures. <\/p>\n<p>\u2018Electrical isolation upon solidifying coupled with pin\/socket position variation are required for open failure. Verified in TS-300 cryo stat testing. Verified in LGN2 testing at KSC with DuPont representative.\u2019<\/p>\n<p>\u2018TDR (Time-Domain Reflectometry) testing resulted in determining that the ET-125 failure existed at the feed through and most probably at the external connector to feed through interface.<\/p>\n<p align=\"left\">\u2018Failure signature (make\/break) and reasonable cause hypothesis support external connector being suspect: Two events required for make\/break \u2013 non conductive contamination at cryo temperatures and movement. Thermal effects, cryo pumping opportunity, Krytox, silicone contamination possibility point to external connector.\u2019<\/p>\n<p>Testing of the removed ET-125 External Feed-through connector at the TS-300 test stand&nbsp;located at the Marshall Space Flight Center (MSFC) also cleared the internal connector \u2013 which would have been a bigger problem, due to the requirement of rollback to remove the hardware.<\/p>\n<p>\u2018Root cause positively identified as cryo induced contamination coupled with pin\/socket movement which contamination findings support,\u2019 added the test results.<\/p>\n<p>\u2018Root cause is not transferable to internal connector because thermal profile doesn\u00e2\u20ac\u2122t support pin socket thermal gradients resulting in internal connector opens. Solid air, ice not possible inside tank. ET-125 Internal connector sockets are contamination free.\u2019<\/p>\n<p align=\"left\">The first of two Flight Readiness Reviews (FRRs) will be conducted on Friday, which will finalize the paperwork ahead of launch, following Atlantis\u2019 stay at Pad 39A since November. No issues are currently being worked on the vehicle, as repair work is completed on ET-125.<\/p>\n<p>\u2018Doing well on Orbiter-side at the pad. Work is planned out and they are flexible with this work at the pad,\u2019 noted&nbsp;Deputy Shuttle&nbsp;Manager John Shannon at the latest Stand-up\/Integration meeting.&nbsp;<\/p>\n<p>\u2018ET work and trimming are complete. Enclosures were removed. Cures are up next week. In good position to get vehicle in launch configuration.<\/p>\n<p>\u2018ECO efforts are complete. Working through one additional issue associated with fleet clearance for a TPS observation seen in production. <\/p>\n<p>\u2018Expect clearance of this before FRR. Have a series of qual tests in work to support ET-125 ECO mods, all of which are on schedule.\u2019<\/p>\n<p><em><u><img loading=\"lazy\" decoding=\"async\" style=\"WIDTH: 205px; HEIGHT: 147px\" height=\"130\" alt=\"\" hspace=\"5\" src=\"http:\/\/forum.nasaspaceflight.com\/forums\/get-attachment.asp?action=view&amp;attachmentid=13815\" width=\"200\" align=\"left\" vspace=\"5\" border=\"0\/\"><font face=\"Verdana\" color=\"#0000ff\"><em>**Ride home through the fire,&nbsp;sparks&nbsp;and plasma of re-entry with Atlantis, Discovery and Endeavour.&nbsp;FIVE&nbsp;Stunning high quality&nbsp;2hr, 355-400mb Camcorder and HUD videos \u2013 from payload bay closure \u2013 through re-entry with an&nbsp;astronaut held camcorder video \u2013&nbsp;to post landing \u2013 several more videos showing landing from 90,000 ft also available and HUD videos from STA landings. Includes HALO II Re-entry video, and re-entry videos from Gemini and Apollo (converted from 8mm)**<\/em><\/font><\/u><\/em><\/p>\n<p>Launch Commit Criteria:<\/p>\n<p>No ultimate decision has been made on the LCC requirement for the ECO sensors during the STS-122 countdown, with the final&nbsp;debate heading for the Flight Readiness Reviews.<\/p>\n<p>However, an interesting set of opinions, from related STS departments, showed an across-the-board change to the opinion that the LCC should remain as the standard 3\/4 LCC for the sensors, rather than the 4\/4 \u2013 as brought in for the second launch attempt in December. <\/p>\n<p>Notably, departments, such as the conservative JSC Engineering \u2013 which had previously called for 4\/4 \u2013 came into line, following the confirmation that a root cause had been found.<\/p>\n<p>\u2018JSC Engineering Directorate Position on LCC for STS-122 ECO System is 3 of 4,\u2019 noted their presentation. \u2018Root cause identified and isolated to contamination on external pin socket connection. Very small residual risk exists that similar failure mode exists at internal pin\/socket connection.<\/p>\n<p>\u2018Design modification which includes solder the pin to socket, Teflon insert, and strain relief eliminate this common cause failure mode.<\/p>\n<p>\u2018Comprehensive qualification test program implemented to demonstrate performance and reliability of the modified feedthrough connector. Great care and expertise used during flight unit soldering and assembly.<\/p>\n<p>\u2018Flight unit post soldering inspections and high strength margins demonstrated by successful qualification testing ensure flight worthiness of flight units. Helps mitigate the fact that acceptance test on ET-125 feedthrough modification did not include vibration or cyro exposure.<\/p>\n<p>\u2018Appropriate LCC is 3 of 4 to allow use of redundancy in the system to deal with other potential ECO system failure.<\/p>\n<p>The Orbiter Project Office (OPO) at the Johnson Space Center (JSC) in Houston concurred, adding that the use of a fix, utilized by the Atlas Program \u2013 one which involved the soldering of the pins on ET-125 and ET-126\u2019s connectors&nbsp;\u2013 added to the overall confidence.<\/p>\n<p>\u2018This cause identification and corrective action is consistent with findings of Atlas Program tank feedthru connector failure resolution. There have been no recurrences of open circuits at this interface since this fix was put in place on the Atlas Program,\u2019 added OPO\u2019s overview.<\/p>\n<p>\u2018The physics behind the failure mechanism is still being investigated. However, by soldering the external pin interface, the failure mode and its affects at this interface has been eliminated.<\/p>\n<p>\u2018STS-122 tanking test data and the subsequent investigations have resolved previously theorized common cause concerns with other ET and Orbiter hardware (Point Sensor Electronics Box, Electrical monoball, production breaks, etc.,) that provide a high degree of confidence in the ECO system with the implementation of the feedthru connector fix<\/p>\n<p>\u2018The ECO circuits always fail \u2018WET\u2019 per design during each tanking with anomalies. For tankings with anomalous sensor circuits, the remaining healthy circuits have always demonstrated functionality (transitioned to dry at the correct time during tank drain)<\/p>\n<p>\u2018OPO recommends the use of the flight bypass for an ECO circuit known to be failed WET to preclude a DRY flash if the sensor circuit recovers following arming.\u2019<\/p>\n<p>Another article will follow Friday\u2019s FRR. 500 pages worth in L2 \u2013 next article Saturday.<br \/><em><br \/><\/em><font color=\"#0000ff\"><em>L2 members<\/em><\/font><em>: All documentation&nbsp;\u2013 from which the above article has quoted snippets \u2013 is available in full in the related L2 sections, updated live.<\/em><\/p>\n<p><font color=\"#0000ff\"><\/font><font face=\"Arial\"><\/font><font color=\"#0000ff\" size=\"2\"><em>Click here for MaxQ\u2019s Stunning Apollo I\/Challenger\/Columbia&nbsp;Tribute&nbsp;Video \u2018New Days Will Rise\u2019.<\/em><\/font><\/p>\n<p><em><font face=\"Arial\" size=\"2\">**STARLIGHT: NEW STS-117 MISSION&nbsp;REVIEW&nbsp;MUSIC&nbsp;VIDEO**<\/font><\/em><em><font face=\"Arial\" size=\"2\">&nbsp;\u2013 STS-118 and STS-120&nbsp;Mission review video also available.<\/font><\/em><font face=\"Arial\"><\/font><font size=\"2\"><em>&nbsp;<\/em><\/font><\/p>\n<p><font color=\"#ff0000\">**ROCK YOU LIKE A HURRICANE: STS-117 MISSION&nbsp;REVIEW&nbsp;MUSIC&nbsp;VIDEO \u2013 AS SEEN BY THE STS-117 CREW!!**<\/font>&nbsp;-.<br \/><font size=\"1\">(<em>Video section is FREE, but you need to sign up as a member of the forum to enter the video section of the site. We only use your e-mail to send you your password. It will not be used for spam etc.)<\/em><\/font><em><\/em><em><font size=\"2\"><\/font><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>ECO (Engine Cut Off) sensor anomalies are caused by \u201csubstantial amount of Krytox grease and silicon contamination\u201d on the External LH2 Feed-through connector plug and pins, testing has found, as STS-122 marches \u2013 with confidence \u2013 towards launch next month. A major discussion on the LCC (Launch Commit Criteria) has also been conducted, ahead of [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-41496","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41496"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=41496"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41496\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}