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<\/font><\/p>\n ET-120 went through two tanking tests prior to STS-114 last year \u2013 before being replaced by ET-121 for the mission. Following evaluations on ET-120\u2019s PAL ramp, hairline cracks were found, which it is understood was a direct result of the two \u2018cryo cycles\u2019.<\/font> <\/p>\n <\/font><\/p>\n While a tanking test won\u2019t affect the current NET (No Earlier Than) launch date of July 1, the rationale for adding a Tanking Test \u2013 soon after Discovery is rolled out to the pad \u2013 simply for the evaluation of the new ECO sensors, appears unbalanced on the pros and cons.<\/font> <\/p>\n <\/font><\/p>\n Should there be another problem with the ECOs, it will show up during the launch countdown \u2013 as they did during STS-114\u2019s first launch attempt last July, thus deeming the Tanking Test as non-essential.<\/font> <\/p>\n <\/font><\/p>\n <\/p>\n A new dual-screen diffuser (duplex) version, installed into ET-120, was deemed responsible for the over-cycling, which was to such an extent that it nearly over-diffused the amount of GHe (Helium) entering the tank. <\/font><\/p>\n ET-121 \u2013 which eventually flew with Discovery on STS-114 \u2013 used the traditional single-shute-wire weave screen on its diffuser, yet it appeared the problem remained, as the ET was only one cycle away from breaching the LLC during Discovery\u2019s countdown.<\/p>\n Previous reasoning relating to the cycles on STS-114\/ET-121 can be viewed here: **Related Diffuser Article**<\/font><\/p>\n Evaluations are still taking place on the request for a Tanking Test, with another MMT Sim set to take place next week (S0044).<\/font> These Sims will evaluate the rationale on the requirement for further data.<\/font><\/font><\/p>\n <\/font>Images of the damage can be viewed on L2<\/font><\/p>\n <\/font><\/p>\n <\/font><\/p>\n <\/font><\/p>\n <\/em><\/font> <\/font><\/p><\/p>\n","protected":false},"excerpt":{"rendered":" NASA is considering the inclusion of a Tanking Test into STS-121\u2019s processing flow, in order to test ET-119\u2019s new ECO (Engine Cut Off) sensors, which are currently being installed as replacements during change-out. The inclusion of the Tanking Test requires approval from the KSC launch director \u2013 and discussions have been met with protests over […]<\/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-42107","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/42107"}],"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=42107"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/42107\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=42107"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=42107"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=42107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/font><\/font><\/font><\/p>\n
However, upon inquires on whether any other issues may have been adding pressure for a Tanking Test, sources note a wish to monitor the amount of cycles on the LH2 pressurization relief valve (hydrogen vent valve), which breached Launch Commit Criteria (LCC) \u2013 on both tanking tests, involving ET-120.<\/font> <\/p>\n
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<\/font><\/p>\n<\/font>Work is currently proceeding on changing out the LH2 ECO sensors in the aft dome area of ET-119, while at the other end of the tank, work on changing out the vent and relief valve has been halted due to foam damage, sustained when a portable light fixture fell on to the area near the top of the tank.<\/p>\n
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