**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> **<\/em>\n<\/p>\n \n STS-122 L2 Special NOW LIVE. **Click here for sample of L2 menu and content**<\/em><\/em><\/p>\n **STS-122 Mission Documentation Build-Up Surge already in work on L2 \u2013 now including 12 MOD Flight Readiness Review (FRR) Presentations \u2013 Nov 5, Baselines and Mission Overviews.<\/em><\/p>\n **Now includes 17 Shuttle FRR Presentations \u2013 Nov 13**<\/em><\/p>\n **LIVE updates on Discovery STS-120 Post Flight and STS-124 Processing**<\/em><\/p>\n **LIVE news updates on Atlantis STS-122 Pad Processing**<\/em>\n<\/p>\n \n<\/em><\/p>\n <\/p>\n<\/p>\n SpaceX (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n<\/p>\n <\/em><\/p>\n <\/em><\/p>\n<\/p>\n <\/em><\/p>\n Article:<\/p>\n Called Flash Thermography, the results produced anomalous readings near the junction between panels along the edge of the T-seal. The panel was not damaged, but based on NESC (NASA Engineering and Safety Center) concerns about possible spalling, where small pieces could flake off and possibly compromise the integrity of the heat shield, that panel was replaced.<\/p>\n Objections were raised during preparations for STS-117, and concern escalated prior to STS-120 when the NESC recommend replacement of three panels based solely on the thermography testing.<\/p>\n The RCC panels have always been examined with x-rays and ultrasound techniques when delivered from the factory.<\/p>\n Between flights, a technician physically \u2013 and painstakingly \u2013 tapped every inch of over forty panels, watching with a 10-power jeweller\u2019s eyeglass, subjectively judging the response of the \u2018tap.\u2019<\/p>\n The recently developed \u2013 and not fully certified \u2013 thermography technique utilizes a split-second flash from a heat-lamp. As the panel cools, any problems below the surface (manufacturing defects, air pockets, etc.) would be visible as changes in the cooling rate. Roughly 320 pictures of each wing and 85 pictures of the nose cap give NASA over a terabyte of infrared imagery data, which is then reviewed for sub-surface flaws.<\/p>\n Those images are converted into digital line scans, using the brightness values of individual pixels. An Indication Amplitude, greater than 0.2, was utilized as a number to be \u2018concerned\u2019 with. That particular number is fairly arbitrary, with data showing Atlantis has one panel (16L) with an IA of 0.31.<\/p>\n Inspections didn\u2019t show any heat damage, which indicates that the pieces came off after re-entry, during higher aerodynamic pressures and after the point where the SiC coating is needed. Any piece that might break off during launch would be visible during the FD2 inspection process, and could be repaired via the NOAX tile repair capability.<\/p>\n Despite FD2 and FD14 OBSS (Orbiter Boom Sensor System) imagery and data showing no issues with Discovery\u2019s panels during STS-120, NASA is determined to gain a better understanding of the problem.<\/p>\n This has led to the formation of a Tiger Team \u2013 the name for a high level investigation team \u2013 formed to determine the root cause of the coating liberation, establish pass\/fail criteria for areas where the coating is possibly compromised, and recommend a replenishment strategy to USA for obtaining spares.<\/p>\n The SiC Liberation (SiCL) team consists of personnel from various NASA centers and contractors, and a wide range of discipline experts. NESC will also assist with an independent assessment.<\/p>\n A 62 page presentation (on L2) presented to shuttle management last week, outlined the team charter, which the Tiger Team is tasked with, \u2018determining, to the extent possible, the mechanism and root cause of RCC SiC coating liberation at the slip side joggle areas,\u2019 noted the presentation.<\/p>\n \u2018Through inspection, test and analysis establish pass\/fail criteria for suspect coating areas that allow removal and replacement of Orbiter RCC before flight.<\/p>\n \u2018Identify threats to spares and recommend a replenishment strategy to USA logistics based on the root cause identification and inspection strategy.\u2019<\/p>\n Unfortunately there is a very limited supply of RCC joggle material, and even fewer pieces with high (>0.2) IA scan values. So structural modeling, combined with thermo-mechanical tests using small \u2018joggle coupons\u2019 will be needed.<\/p>\n The highly-detailed fault tree \u2013 which even noted evaluations into the possibility of foreign object damage to the shuttle while on the cross-country trip back from west coast landings \u2013 includes the following for potential causes: \u2018Fabrication Defects. Ferry Flight Operations. Flight Environment. Launch Pad Environment. Repairs. Refurbishments. Ground Handling.\u2019<\/p>\n The investigation is expected to take nine months to complete, and since the shuttle will continue to fly as this the evaluations are ongoing. Some results that can be determined rapidly are expected to be presented at the STS-123 OPO (Orbiter Project Office) FRR on January 24th 2008.<\/p>\n The preliminary goal is to identify any panels that need replacement within a month of the vehicle entering the VAB (Vehicle Assembly Building), and setting a final decision point around two weeks prior to rollout.<\/p>\n Currently, as listed in the presentation, the current candidates for the possible contributing factors of the RCC issue are wide-ranging.<\/p>\n \u2018Subsurface oxidation resulting in loss of SiC coating adherence to the C\/C substrate. Pressure build-up below the SiC coating as a result of volatiles formed from the Type A\/TEOS in the C\/C voids and sealed cracks.<\/p>\n \u2018Modifications in the refurbishment cycle; Type A being applied before TEOS, filling the voids and volatiles formed (similar to 2). Thermomechanical stresses\/fatigue between the SiC coating and C\/C substrate resulting in degraded coating\/substrate adherence.<\/p>\n \u2018Thermal cycling (fatigue) while on-orbit and thermal differential during entry between RCC panel, attachments and front spar. Increased heating in the joggle region due to gap\/step dimensions being out of specification. Fabrication induced separation between SiC coating and C\/C substrate as a result of convoluted plies during initial lay-up.\u2019<\/p>\n Any combination of the above, the presentation noted, is a possible contributing factors that could lead to a SiC liberation from the RCC. <\/p>\n<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" NASA has set up a special Tiger Team to investigate the root cause of a potential issue with the shuttle\u2019s Reinforced Carbon-Carbon (RCC) leading-edge panels, which was highlighted at STS-120\u2019s Flight Readiness Review (FRR).The process will work in two stages \u2013 near term \u2013 with opening results expected ahead of next year\u2019s STS-123, and long […]<\/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-41543","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41543"}],"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=41543"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41543\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41543"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41543"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/em>L2: STS-122 to STS-127 documentation already available.<\/em><\/p>\n
The issue was uncovered following the STS-114 mission, after a new method of inspecting the panels was developed after the loss of Columbia.<\/p>\n
The Silicon Carbide (SiC) coating has only broken off two panels during shuttle flights. STS-102 saw the loss of a 2.0\u201d x 0.3\u201d piece \u2013 while STS-103 was observed to have lost a 1.6\u201d x 0.4\u201d piece.<\/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><\/p>\n
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\n<\/em>L2 members<\/em>: 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