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Other notes of reference relate to the alternative landing site, via weather latest and a number of broken lights on the runway at Edwards Air Force Base\u2019s Dryden facility.<\/p>\n
\u201cDryden update: All red lenses on the 6500 ft. and 7500 ft. PAPIs have shattered,\u201d noted one example. \u201cSpare lenses located at KSC and are being shipped overnight. We should be installing them Thursday afternoon (11\/13).\u201d<\/p>\n
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Such is the nature of STS-126\u2019s smooth countdown, no L-1 brief is required by the MMT. This follows an issue-free L-2 MMT brief, which reviewed a number of previously documented notes of interest \u2013 all of which have been cleared.<\/p>\n
A large amount of the L-2 MMT documentation (11 presentations in total \u2013 and available on L2) referenced the recent report \u2013 via a large Program Requirements Control Board) presentation \u2013 about the singular lack of a government inspector being used to certify the wiring vendors\u2019 report, as per wiring used on the SSMEs, SRBs etc. Purely a paperwork issue that has since been resolved.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2008\/11\/a214.jpg\")
Other presentations dealt with recent issues on Endeavour, such as the Integrated Display Processor issue (CRT2 MEDS 1553), which has also been cleared for flying \u2018as-is\u2019.<\/p>\n\u201cObservation:: Multifunction display unit (MDU) CRT2 annunciated to integrated display processor 2 (IDP) minor error message \u201cCRT2 MEDS 1553 bus error\u201d on numerous power ups starting on 10\/31\/08,\u201d noted the Orbiter Project presentation. \u201cError message indicates a transient, self-clearing loss of communication with its IDP during power up when using the ground processing technique<\/p>\n
\u201cIDP error log indicates error due to \u201cbusy bit\u201d in MDU status response and not the result of a 1553 bus transmission error. Function of IDP and CRT unaffected by the message.\u201d<\/p>\n
Because the issue only occurs during a specific power up sequence, the risk of the display being lost during flight is small \u2013 due to the unit remaining powered up during the mission. Engineers will troubleshoot the problem once Endeavour is back in her Orbiter Processing Facility (OPF), post flight.<\/p>\n
\u201cFlight Rationale: Error only occurs during a particular power on sequence that is used exclusively during ground processing. Error message is nuisance only, transient \/ self-clearing, is transparent to the crew, and does not impact hardware functionality. Adequate redundancy exists for worst case failure causing complete loss of this CRT MDU slot<\/p>\n
\u201cRecommendation: Accept observed signature for STS-126 and defer further troubleshooting to next flow.\u201d<\/p>\n
The largest L-2 MMT presentation was dedicated to an issue noted on the previous flight \u2013 STS-124 \u2013 which outlined the problem with Discovery\u2019s multiplexer-demultiplexer (MDM) flight aft 2 (FA2) \u2013 which was replaced ahead of flight, after causing an off-nominal 2-1-1 spilt of the orbiter\u2019s GPCs (General Purpose Computers).<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2008\/11\/a34.jpg\")
The 51 page presentation included numerous images of the electronics \u2013 even at the microscopic level \u2013 showing the failed diode in amazing detail.<\/p>\n\u201cObservation: During S0024 (hypergolic loading) operations on OV-103 for STS-124, the primary port of multiplexer-demultiplexer (MDM) flight aft 2 (FA2) failed with Non Universal I\/O,\u201d noted the presentation.<\/p>\n
\u201cThe failure resulted in a data processing system (DPS) redundant set split of the general purpose computers (GPCs). Root cause found to be failed diode on the SMIA (serial multiplexer interface adapter).<\/p>\n
\u201cConcern: Non-universal I\/O failure scenarios can range from minor impacts to engaging the backup flight software (BFS) system.\u201d<\/p>\n
Flight rationale was already in place for STS-126, which has been backed up by the lack of related issues during the same stage of the processing flow for Endeavour.<\/p>\n
\u201cFlight rationale for STS-126: 1N3600 diode failure trend is low. Total of 17 failures all lots, all vendors for 1N3600. MDMs are powered on during any vehicle power up so more likely to see a failure occurrence on the ground than in flight,\u201d added the presentation.<\/p>\n
\u201cSystem response to non-universal errors was nominal and per design. Flight rules document response(s) to comparable failure during flight. Crew \/ ground controllers trained to respond to observed conditions.<\/p>\n
\u201cDocumented data processing system functional redundancy maintained via the backup flight system (BFS) for Ascent\/Entry flight phases.\u201d<\/p>\n
Upcoming milestones for STS-126 include the retraction of the Rotating Service Structure (RSS) at around 23:30 local time on Thursday night, with tanking of External Tank (ET-129) due to begin around 10:30 local time on Friday.<\/p>\n
L2 members<\/em><\/em>: All documentation \u2013 from which the above article has quoted snippets \u2013 is available in full in the related L2 sections, now over 4000 gbs in size.<\/em><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"
A loose washer on a ground support carrier plate is the only reported issue, as Endeavour heads towards launch day \u2013 in an amazingly issue-free S0007 launch countdown for STS-126. This follows a review of outstanding paperwork during the Mission Management Team (MMT) L-2 meeting. Loading of Endeavour\u2019s Power Reactant Storage and Distributation systems was […]<\/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":[9223,9122,9219],"class_list":["post-41265","post","type-post","status-publish","format-standard","hentry","category-news","tag-add-new-tag","tag-gucp","tag-sts-126"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41265"}],"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=41265"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41265\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41265"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}