**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 **STS-123 Documentation build-up already in works, with mission baseline presentations and processing documentation**<\/p>\n **LIVE updates on Atlantis STS-122 Troubleshooting Latest**<\/em><\/font><\/p>\n Company News (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n **LIVE news updates on Endeavour STS-123 Processing**<\/font><\/em><\/p>\n **LIVE updates on Discovery STS-120 Post Flight and STS-124 Processing**<\/em><\/font><\/p>\n<\/p>\n The gear on Endeavour had been retracted over the weekend, as her processing flow inside OPF-2 (Orbiter Processing Facility) continues to push towards rollover next month (January 9). The bulk of work has been completed on the orbiter, with forward, midbody and aft closeouts on schedule ahead of the holidays. <\/p>\n As part of the closeout procedures, Endeavour\u2019s gear was lowered, at which point engineers noticed that the LH MLG was leaking fluid around the gland nut area. Such was the rate of leaking, a puddle had formed on the gear, in the scissors of the strut, and down the side of the MLG door. <\/p>\n Ironically \u2013 and fortunately \u2013 a couple of specialist engineers were already on site, completing work on Discovery\u2019s landing gear. \u2018R&R\u2019d main landing gear strut seals on weekend. The LH seal was upside down. Doing a hydraulic service check and leak check on those struts to be in position to complete testing,\u2019 confirmed processing information. <\/p>\n Managers met to discuss the forward plan, with the consensus pointing towards a full R&R of the seals in the strut, rather than leaving as-is with flight rationale. As of Wednesday, both LH and RH struts will be R&R\u2019ed. All the wheels have been removed ahead of the effort.<\/p>\n The Orbiter landing gear systems use an oleo-pneumatic shock absorber strut design to provide landing load attenuation. Strut design consists of a piston\/axle assembly and outer housing filled with hydraulic oil on top of nitrogen gas, separated by a floating internal piston. <\/p>\n The system has performed without any major issue since STS-1, though the shock strut static and dynamic seals \u2013 which prevent external leakage of hydraulic oil \u2013 are now starting to come into focus. <\/p>\n The incident with Endeavour mirrors a similar leak on Discovery\u2019s Right Hand MLG strut, which slightly delayed her rollover ahead of STS-120. A United Space Alliance (USA) investigation into Discovery\u2019s leak discovered the RH MLG strut dynamic seal assembly was not installed \u2018per print\u2019 configuration, and hadn\u2019t been for 27 missions.<\/p>\n \u2018Potential for strut hydraulic fluid leak past strut seal. Excessive leakage could cause decrease\/loss of damping ability of the shock strut during landing (Crit 1\/1 failure mode),\u2019 noted the presentation associated with the investigation, explaining the recent R&R work inside the OFP. <\/p>\n \u2018Left hand (LH) MLG strut seal on OV-103 (Discovery) also suspect as it was installed at the same time period as the RH (Right Hand) side.\u2019 <\/p>\n It was the fine work by the Goodrich and USA engineers that enabled the changeout of the suspect seals on Discovery to take place without a major delay to STS-120\u2019s rollover. That experience is likely to prevent any delay to Endeavour \u2013 though the actual rollover will be dependant on the ongoing STS-122 troubleshooting. <\/p>\n It was also Goodrich engineers that spotted the incorrect installation of the seals, after the R&R effort on Discovery\u2019s leaky strut. The fact that it was only spotted recently has a lot to do with the complexity of the system, which uses both static and dynamic seals to prevent the external leakage of hydraulic fluid.<\/p>\n The wedge shaped outer ring provides added forces on Teflon foot seal during gear touch down pressure spike, while the Buna-N O-ring acts as a static seal and spring, to maintain the Teflon foot seal against the piston. <\/p>\n The Static seal is housed in the lower bearing assy OD, sealing against the fixed outer cylinder ID. Middle & bottom \u2013 spare seals provide field R&R capability.<\/p>\n Regardless of the incorrect installation of the seal, the orbiters weren\u2019t under any threat of a problem at landing, following the findings of the investigation.<\/p>\n \u2018MLG technical community assessment (NASA, contractor and suppliers) concluded that the dynamic seal assembly will function as intended even without Teflon wedge ring in the proper location,\u2019 noted the presentation.<\/p>\n \u2018Seal is contained in groove \u2013 dynamic hydraulic pressure spike at MLG touch-down forces Buna-N O-ring and primary Teflon seal against shock strut. Wedge provides additional sealing capability for high pressure spike. No expectation of gross seal failure based on failure analysis findings.\u2019<\/p>\n What will be of interest to engineers is the potential of any commonality with the leak currently observed on Endeavour, given the incorrect installation findings only referred to Discovery. This information may be forthcoming via the R&R effort on Endeavour this week.<\/p>\n Another note relating to Endeavour\u2019s landing gear was mentioned in processing information this week, this time with her nose gear. This will also be repaired this week, as processing continues along the \u2018green\u2019 timeline for STS-123 and LON support of Atlantis.<\/p>\n \u2018Were trying to do landing gear functional on weekend, but had a cracked tile at nose landing gear which must be repaired first. Want to do integrated hydraulic operations Friday and then start landing gear functional,\u2019 added processing information, before rounding up other key elements of the march towards launch.<\/p>\n \u2018Have 20 tile cavities left, which is very manageable between now and rollout. SRB stacking was completed, are just doing closeouts. On ET, all four feedline brackets have been sprayed. All work on this ET is on schedule (pending associated troubleshooting relating to STS-122\u2019s ET). Will standby to see what work is needed on ET.\u2019 **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> -. Reminiscent of a leak on Discovery\u2019s landing gear ahead of STS-120, a diaper has been placed around the Left Hand Main Landing Gear (LH MLG) of Endeavour, after it was observed to be leaking fluid. Endeavour is tasked with the roles of the Launch On Need (LON) rescue orbiter for STS-122, while she prepares for […]<\/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-41527","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41527"}],"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=41527"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41527\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41527"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41527"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41527"}],"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
<\/em>Endeavour Latest:<\/u><\/em><\/p>\n
The engineers \u2013 from Goodrich \u2013 immediately wrapped a diaper around the leaking strut, and are currently evaluating the leak rates in both the vertical and horizontal positions. <\/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
The Dynamic seal assembly consists of to Teflon rings and a Buna-N O-ring, housed in the lower bearing assy ID, which seals against the sliding main piston\/axle assembly. <\/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":"