- \n
- Shuttle Fleet Updates<\/li>\n
- L2 STS-132 Special Section<\/li>\n
- L2 STS-133 Special Section<\/li>\n
- To Join L2 \u2013 click here<\/li>\n<\/ul>\n
Return To Flight modifications to the tank continued throughout the second half of the last decade, with further lessons learned on areas such as the Ice Frost Ramps (IFRs) \u2013 which have seen hardly any foam shedding since redesigns were implemented.<\/p>\n
However, before a tank leaves the pad with the rest of the stack, the three hour process of loading the ET with LH2 and LOX requires the hardware to perform as advertised, notably of late with the Ground Umbilical Carrier Plate (GUCP) \u2013 the cause of scrubs during both STS-119 and STS-127.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2010\/06\/g7.jpg\" "\\"g7\\"")
Since a redesign to a two-part seal \u2013 and the correction of misalignments on the External Tank Carrier Assembly (ETCA) mounts, or feet \u2013 no leaks have been detected during topping operations, as was the case with STS-132.<\/p>\n\u201cPre-launch Performance Assessment: Electrical and Propulsion systems performed nominally. No leakage detected at the GUCP during the transition to topping. Total of ten (10.3) pre-press cycles as predicted,\u201d noted the STS-132 External Tank IFA Review presentation \u2013 all 16 IFA presentations available on L2.<\/p>\n
For all 17 NASASpaceflight.com articles on the GUCP, click here: http:\/\/www.nasaspaceflight.com\/tag\/gucp\/<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2010\/06\/A316.jpg\" "\\"A3\\"")
Several observations were logged after tanking by the Final Inspection Team (FIT), who photograph the tank for issues such as ice build up and any cracks caused by the cryo conditions associated with tank loading. However, all were cleared during the business end of the countdown by the Mission Management Team (MMT).<\/p>\n\u201cTPS performance acceptable per (requirements): Typical TPS crack on -Y Vertical Strut. Thick shell ice ball at LH2 Feedline inboard closeout near LH2 tank aft dome. LCC (Launch Commit Criteria) Ice-01 violation \u2013 Crack at diagonal strut fitting closeout inboard near interface to the tank,\u201d added the presentation. LCC Waiver processed to accept condition. Explained condition \u2013 same mechanism that induces crack at Vertical Strut.<\/p>\n
\u201cPost Flight Performance Assessment Complete: Electrical and Propulsion systems performed nominally. Structural System performance nominal. ET\/Orbiter separation and ET Disposal nominal. TPS imagery assessment complete. Umbilical stills and video, Handheld, Cockpit camera and SRB imagery reviews complete.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2010\/06\/A414.jpg\" "\\"A4\\"")
Only three areas of foam loss \u2013 four events in total \u2013 were noted on the IFA presentation, all deemed as minor. None of the liberations are believed to have impacted the orbiter \u2013 although none would have threatened any damage of note on Atlantis\u2019 TPS due to their small mass.<\/p>\n\u201cPost flight performance assessment identified the following ET TPS debris events of note in critical debris zone for further scrutiny,\u201d the presentation continued.<\/p>\n
\u201cXT 1593, LH2 Ice Frost Ramp: Two Events: Mass 1: ~0.080 lbm total (likely multi-piece event). Mass 2: ~0.001 lbm MET (Mission Elapsed Time): Indeterminate (possible 323 or 374 event). Failure mode: Cryo-pumping (loss 1) Risk Assessment Mass: \u2264 135 Seconds: 0.25 lbm > 135 Seconds: 0.25 lbm.<\/p>\n
\u201cXT 1129, LO2 Feedline Base Closeout: Mass: ~0.050 lbm MET: ~160 sec. Failure mode: Cryo-Pumping Risk Assessment Mass: \u2264 135 Seconds: 0.077 lbm > 135 Seconds: 0.077 lbm.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2010\/06\/A381.jpg\" "\\"A38\\"")
\u201cXT 1102, Intertank Acreage: Mass: ~0.016 lbm MET: ~129 sec. Failure mode: Bond Adhesion Risk Assessment Mass (Void delta P): \u2264 135 Seconds: 0.004 lbm > 135 Seconds: 0.015 lbm.\u201d<\/p>\nOnly the intertank loss occurred near to the time foam liberations may have enough energy \u2013 via the remaining air resistance as the stack leaves the atmosphere \u2013 to be a threat to the orbiter, although it would have had to been of a higher mass in such an event.<\/p>\n
Encouragingly, it was only a single area of intertank foam loss, which adds additional confidence that the mitigation procedures \u2013 set up to reduce the run of numerous intertank foam losses \u2013 have worked to plan.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2010\/06\/A571.jpg\" "\\"A57\\"")
That mitigation effort involved a change to the platforms used to clean the intertanks at the Michoud Assembly Facility (MAF) ahead of foam application, which reduced the possibility for dust to remain on the structure, in turn reducing the adhesive properties between the aluminium and the foam.<\/p>\n\u201cIntertank imagery reveals only one loss similar to those as observed on ET-131 (low bond adhesion induced losses with stringer top primer visible), and no losses observed from bond adhesion test repair sites,\u201d the presentation noted.<\/p>\n
While bond tests \u2013 sometimes known as plug\/pull tests \u2013 will continue to be carried out in the Vehicle Assembly Building (VAB), engineers are not required to carry out additional tests on additional areas, as previously called for.<\/p>\n
\u201cIntertank acreage foam loss at Xt 1102. Failure mode not documented \u2013 IFA recommended (IFA-STS-132-T-002). This loss is consistent with our understanding of this failure mode and within expectations since this failure mode was identified on ET-131.<\/p>\n
\u201cNo additional bond adhesion tests are planned for ET-137 based on process similarity and performance of ET-136.\u201d<\/p>\n
STS-132 Specific Articles: http:\/\/www.nasaspaceflight.com\/tag\/sts-132\/<\/p>\n
All other areas of the tank, which have suffered from foam liberations during flights in recent years, were classed as clean, confirming the excellent performance of the tank. These results will next become part of the baseline for the STS-133 Flight Readiness Review (FRR).<\/p>\n
\u201cAll LH2 Ice Frost Ramps intact except for loss as noted at Sta 1593. Nominal popcorning\/charring observations from LO2 Ice Frost Ramps,\u201d added the presentation in conclusion. \u201cNominal popcorning\/charring\/ablation observations from aft hardware closeouts.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
A multi-stage approach to the mitigation of foam liberations from the intertank region of the External Tanks (ETs) continues to pay dividends, as STS-132\u2019s In Flight Anomaly (IFA) review pointed to yet another clean tank \u2013 with only one area of notable foam loss from Atlantis\u2019 tank. The results have removed the requirement for additional […]<\/p>\n","protected":false},"author":1,"featured_media":29735,"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":[9021,3485],"class_list":["post-40740","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-et","tag-sts-132"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40740"}],"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=40740"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40740\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/29735"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=40740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=40740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=40740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}