**The most comprehensive collection of Shuttle, Ares, Orion and ISS related presentations and mission documentation, plus expansive daily processing documentation and updates are <\/em>available to download on L2<\/em><\/font> **<\/em><\/font><\/p>\n STS-122 L2 Special NOW LIVE. **Click here for sample of L2 menu and content**<\/font><\/em><\/p>\n <\/font>**STS-122 Special: 12 MOD Flight Readiness Review (FRR) Presentations, Baselines and Mission Overviews. 17 Shuttle FRR Presentations. Payload Presentations and vast amounts of live, uploaded images and presentations. Installation Movies (several) \u2013 already 1400 megabytes strong** <\/font><\/em><\/p>\n **COMPLETE Section on ECO issues and troubleshooting, graphical and data**<\/p>\n **LIVE updates on Atlantis STS-122 Troubleshooting Latest**<\/em><\/font><\/p>\n **Click here for FRR overview articles: Article 1 \u2013 Article 2** \u2013 Click *HERE* for all our articles on the STS-122 ECO issue.<\/p>\n SpaceX launch tickets (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n Troubleshooting Latest: Thursday\u2019s work involved \u2018tapping\u2019 into LH2 ECO sensors 1 through 4, and the 5 percent sensor wires near orbiter monoball. Resistance checks on ET side of circuit were also conducted, with the use of the Time-Domain Reflectometer (TDR) on all 5 circuits \u2013 with full TDR testing due tomorrow. In readiness of more tests on Friday, engineers also spliced into wiring downstream of the orbiter to the MLP (Mobile Launch Platform). <\/p>\n Friday will involve the baseline TDR run and functional test, while Atlantis is powered up, before the aft is closed ahead of the tanking test next Tuesday \u2013 due to begin at 7am local time. The Rotating Service Structure (RSS) will be moved to its park position at 21:30 local time on Monday. <\/p>\n Thursday saw the fascinating presentation from the ET Project to the PRCB, which covered a vast amount of current thinking, data and background from ECO related events since Return To Flight and STS-122. <\/p>\n The presentation covered the known theories on the initial ECO sensor problems which first showed up during STS-122\u2019s countdown. The lack of problems in recent pre-launch countdowns had raised hopes that the solution \u2013 involving the \u2018hand picking\u2019 of the best sensors \u2013 was the end to the problems on this system. <\/p>\n \u2018Investigation performed and identified most likely cause attributed to loose swages on ECO sensors,\u2019 noted the pre STS-122 ECO events. \u2018Loose swages provide opportunity to break contact between lead wire and sensor. Process enhancements implemented on swages to improve contact.\u2019<\/p>\n Moving swiftly on to the current problem, the ET project outlined their latest findings on what may be causing the problematic ECO sensor readings during the two launch attempts of Atlantis\/STS-122 \u2013 assuming the fault is with the External Tank, and not downstream with the orbiter herself (deemed unlikely). \u2018Level sensors failures \u2013 Remote to Unlikely. Wire Harnesses \/ Splices \u2013 Remote to Unlikely. Feed Through Connector \/ Plug \u00e2\u20ac\u201c Possible,\u2019 the document added, before explaining in relation to the connector: \u2018Requires either contamination of contacts and\/or physical motion \/ damage of mating surfaces during tanking fill and drain. \u2018Most likely \u2018Common Cause\u2019 for STS-122 ECO Sensor Circuit Anomalies Attributed to Feed Through \/ Connector (ET Project Assessment).\u2019<\/p>\n Originally, all ET hardware elements were not believed to be a possible cause of the ECO sensor faults. While the connector is now in focus as a suspect in the fault tree, the ET Project emphasized that background information on the component showed no issues during testing.<\/p>\n \u2018Original design qualified to cryogenic environments with random\/sinusoidal vibration loading at 37 psig (max flight pressure ~34 psig). Thermally shocked 5 times prior to test (-423 degrees F \u2013 +200 degrees F) at 37 psig. ET-120 feed through x-ray and visual inspection performed \u2013 No issues identified.\u2019<\/p>\n The only \u2018recent\u2019 change to the connector was noted as a \u2018glass material change,\u2019 which was implemented in 1999 (ET-120 and subs). However, this change was qualified by similarity analysis (re-qualification not required), with no significant change in mechanical properties.<\/p>\n The presentation also gave a new in-depth look at the ECO sensor readings during both scrubbed launch attempts, characterizing it as \u2018significant new data.\u2019 This new data \u2013 according to the presentation \u2013 has led to the added focus on the LH2 Feed Through Connector as a potential key element in the fault tree.<\/p>\n \u2018Characteristics of the ECO System Anomalies: Timing of the failed wet indications appears related to feed through connector thermal transients during chill down and warm up. Failures are isolated to the sensor circuits in the LH2 bottom connector even though hardware, circuits, and temperatures are very similar to the top level sensors.\u2019<\/p>\n \u2018Plug socket movement is the result of induced loading on plug sockets from forces exerted by vacuum pressure, CTE-motion, and deformation of socket restraint materials (grommet cracking). Circuit opens due to contacts being moved over contamination on pin surface. During drain back \u2013 temperature increases, contamination melts, socket contacts reconnect pins, anomaly clears.\u2019<\/p>\n Additional data is noted, which concentrates on the connector during both of STS-122\u2019s tankings. The findings provide an interesting insight into a three point timeline for the potential of the connector to become compromised by ice contamination, as the tank drops in temperature during cryogenic conditions.<\/p>\n Evaluations can be found in the document, which lists events and observations, via new data, for all four events relating to the launch attempts (tanking and draining). For the first launch attempt, the following observations were found, specific to the connector:<\/p>\n Event 2) (Just prior to ECO sensor readings failure): Pin temperature decreases to < -320 degrees F. Ice contamination increases by freezing air within cavity (now under pressure of 14.7 psid.)<\/p>\n Event 3) (Sensors fail): Cavity temperature < -320 degrees F. Grommet material cracks \/ deforms and degrades capability to maintain sockets in place. Sockets move onto pins entrapping contamination and causing \u2018open\u2019 in connection. Cryopumping continues into all available cavities.<\/p>\n \u2018Supporting Rationale for Postulate Failure Mechanism: Thermal analysis results show that predicted temperatures consistent with air \/ water vapor phase change correlate with sensor circuit anomalies. Cryopumping through wire harnesses and restrictive leak paths well established through tests,\u2019 added the presentation.<\/p>\n \u2018Bench test results show open circuit can be generated by moving socket over pin with solid air on pin surface. Analysis of constituent material CTE deltas show socket motion cannot be precluded. Delta pressure and thermal gradient effects will provide forcing function for socket motion.\u2019<\/p>\n Interestingly, the ET Project gave potential flight rationale for the connector after the tank is \u2018fuelled\u2019 for flight. This may remove concerns about the ECO sensor system malfunctioning during the eight and a half minute ride uphill. This \u2013 pending further data via Tuesday\u2019s tanking test \u2013 may be the key to launching early in January.<\/p>\n \u2018Physics-based understanding supports stable performance following thermal equilibrium. Thermal conditions and forcing functions remain constant through ascent. Cryopumping of ambient air will effectively pot plug with solid air. No further degradation to pin \/ socket contact \u2013 Steady-state condition already achieved,\u2019 added the presentation.<\/p>\n \u2018Tanking test should provide additional data to support understanding of scenario. No further degradation of system (ECO number 3 only fails or all sensor functional). Additional failures should match same time \/ temperature relationship as previous failures. After Steady-State Tanking Conditions are Reached, no Degradation of System Expected.\u2019<\/p>\n There\u2019s still a long way to go before engineers are confident they may have found their root cause, never mind being able to push forward towards launching STS-122 without any concerns relating to the ECO system. However, they are making huge strides in just these opening days to achieving that goal. **STARLIGHT: NEW STS-117 MISSION REVIEW MUSIC VIDEO** \u2013 STS-118 Mission review video also available.<\/font><\/em><\/font> <\/em><\/font><\/p>\n **ROCK YOU LIKE A HURRICANE: STS-117 MISSION REVIEW MUSIC VIDEO \u2013 AS SEEN BY THE STS-117 CREW!!**<\/font> -. Engineers believe they have closed in on the culprit for the ECO (Engine Cut Off) sensors issues during their two launch attempts with STS-122 last week. An expansive presentation was reviewed by Thursday\u2019s Program Requirements Control Board (PRCB), which listed the findings from the External Tank project, which classes the LH2 Feed Through Connector as […]<\/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-41526","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41526"}],"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=41526"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41526\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41526"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41526"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41526"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/em><\/font>L2: STS-122 to STS-127 documentation already available.<\/em><\/font><\/p>\n
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Work started at the pad on Thursday, after the stack was taken out of its launch configuration earlier this week. Troubleshooting remains on track for the tanking test to be conducted next Tuesday. <\/p>\n
<\/font>\u2018Assessed potential ET hardware common cause failure scenarios that could result in STS-122 circuit behavior,\u2019 added the presentation, which showed the LH2 Feed Through Connector is now the only \u2018possible\u2019 cause of the ECO issues, via tank hardware. <\/p>\n
<\/font><\/p>\n\u2018Review of feed through connector design certification and as-built documentation in-work \u2013 No issues identified to date,\u2019 the presentation added, whilst noting expansive background information on the connector, which included: \u2018Acceptance testing complete with no issues. Visual inspections and pin retention tests performed prior to assembly.<\/p>\n
\u2018Postulated Failure Mechanism Summary: Circuit break caused by contamination of contacts between external plug and feed through pins and internal movement of plug sockets. Contamination is the result of condensing and freezing of air and water vapor within connector on feed through pin surfaces. Solid air and ice are effectively electrical insulators. Cryopumping of ambient air is expected through harness. <\/p>\n
Event 1) (Tanking begins): Temperature of pin in feed through connector decreases to < 32 degrees F. Moisture\/vapor freezes on pins resulting in ice contamination.<\/p>\n
**Ride home through the fire, sparks and plasma of re-entry with Atlantis, Discovery and Endeavour. FIVE Stunning high quality 2hr, 355-400mb Camcorder and HUD videos \u2013 from payload bay closure \u2013 through re-entry with an astronaut held camcorder video \u2013 to post landing \u2013 several more videos showing landing from 90,000 ft also available and HUD videos from STA landings. Now includes HALO II Re-entry video, and re-entry videos from Gemini and Apollo (converted from 8mm)**<\/em><\/font><\/p>\n
<\/em>L2 members<\/em><\/font>: All documentation \u2013 from which the above article has quoted snippets \u2013 is available in full in the related L2 sections, updated live.<\/em><\/p>\n
(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><\/font><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"