- \n
- STS-119 LIVE UPDATES<\/li>\n
- L2 STS-119 LIVE (MMT Level)<\/li>\n
- Click here to Join L2<\/li>\n<\/ul>\n
\u201cMER-01 Pre-launch: Low range LH2 Plate Gap Delta Press was out of spec,\u201d noted L2 mission coverage. \u201cHelium purge to the plate gap cavity was increased via console commands and secondary system activation brought the system back within LCC (Launch Commit Criteria) limits.<\/p>\n
\u201cA red crew was successfully sent in to the Pad to adjust a needle valve to increase flow. A waiver to LCC MPS-48 was approved.\u201d<\/p>\n
Discovery\u2019s spectacular launch has been deemed extremely clean, with no foam or debris issues of note found, bar one late release relating to a remnant of a tyvek cover at T+17 seconds into ascent. However, this has already been cleared, due to no impact noted on the vehicle.<\/p>\n
Spaceflight news subscription
<\/path>Space Shuttle models <\/path>Company News <\/path>\n (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n
\u201cTyvek F4D Cover Remnant Partial\/Late Release: Ground imagery showed that when thruster F4D\u2019s (Thruster) Tyvek rain cover released at 5.28 sec MET (~93 fps or 63 mph), a large piece remained attached to the thruster lip as shown (see main article image),\u201d added MER on L2\u2019s mission coverage pages.<\/p>\n
\u201cThis piece is believed to have separated by ~17.3 sec MET (~380 fps or 259 mph). Imagery shows that the piece did not impact the Orbiter. No vehicle\/mission impacts ensued nor are any crew responses required.\u201d<\/p>\n
The covers, which protect the orbiter\u2019s RCS (Reaction Control System) thrusters ahead of launch, are designed to release shortly after lift-off. However, late releases can become a debris concern. Despite the remnant of the cover failing to impact the vehicle, engineers used the event to ensure no damage was possible, even if it had struck Discovery.<\/p>\n
![\"a213\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/03\/a213.jpg\" "\\"a213\\"")
\u201cProblem Impact\/Significance: Testing and analysis of 5-gram Tyvek remnant releases up to 1000 fps have low risk of producing unacceptable damage; however, estimated remnant size for the present F4D failure is greater than 5 g,\u201d added the MER report.<\/p>\n\u201cImpact testing using full-sized covers on RCC samples up to 240 mph produced no damage. Similar impact testing on tile produced minor pitting for impacts between 216 and 268 mph.<\/p>\n
\u201cSince the F4D Tyvek piece that released at ~259 mph was enveloped by full-cover impact testing in terms of both mass and velocity, any impact damage would not be expected to be worse than these ground test results.<\/p>\n
No TPS damage has been attributed to Tyvek cover releases to date. Any TPS damage attributable to these covers would be tracked under TPS damage assessment efforts. This failure has not affected (nor is it expected to affect) FRCS thruster performance. Thruster F4D was first fired at ET Sep and has performed nominally to date.\u201d<\/p>\n
Discovery\u2019s launch came after a few months of evaluations into the Flow Control Valves (FCVs), which led to three valves \u2013 all of which had flow with Discovery four to five times previously \u2013 being \u2018cherry picked\u2019 for the ride to orbit.<\/p>\n
Click here for NASASpaceflight.com articles on the FCV issue since STS-126.<\/p>\n
The concern related to a liberation from one valve\u2019s poppet during Endeavour\u2019s STS-126 launch last year, first seen via ascent data evaluated by the MER engineers.<\/p>\n
However, for STS-119, that data \u2013 as seen in a presentation of their data during ascent \u2013 showed all three valves performed without issue, mirroring each other\u2019s performance via their cycles used to keep the pressurization of the tank at nominal rates.<\/p>\n
During ascent, three indications were registered by the Wing Leading Edge Impact Detection System (WLE IDS), which are used to \u201cfeel\u201d indications of impacts on the RCC panels.<\/p>\n
These sensors are highly sensitive and usually detect \u201cghost impacts\u201d rather than actual impacts, especially on orbit.<\/p>\n
![\"a52\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/03\/a52.jpg\" "\\"a52\\"")
The three indications will be evaluated via their timing and strengths, in collaboration with ascent imagery.<\/p>\n\u201cAll WLE IDS ascent summary data were downloaded and down linked successfully,\u201d noted the FD2 MMT presentation from the WLE IDS team, on L2.<\/p>\n
\u201cTwenty-two (22) half second windows of detailed G time histories were downloaded in order to confirm the implication of cases above 1 Grms. In total, there are three (3) Category I indications; one (1) on the starboard wing and two (2) on the port wing.<\/p>\n
\u201cOverall, background levels for STS-119 are very similar to background levels of previous missions. No data anomalies have been identified. All units triggered on Main Engine Ignition within 0.13 seconds of each other, except unit 1029 on the starboard wing which triggered 0.625 seconds early.<\/p>\n
\u201cThe primary WLES laptop failed to receive data at approximately MET 6 hours. After troubleshooting, ACO and WIS-GFE swapped from the primary to the backup WLES laptop. A complete set of summary data files was received approximately four hours later than expected.<\/p>\n
\u201cWLE IDS On-Orbit Monitoring is currently planned to begin at approximately MET 18 hours with Port and Starboard Group 1.\u201d<\/p>\n
Following MECO (Main Engine Cut Out), Discovery separated from the External Tank (ET), before a camera in the umbilical well of the orbiter takes photography of the departing tank. An issue has been noted on the apparent lack of flashes being seen from the well, which is used to enhance the images.<\/p>\n
\u201cThe Digital Umbilical External Tank camera flash was not observed in the live video during ET separation,\u201d added the MER. \u201cBased on the video downlinked thus far, the analysis confirmed the observation.<\/p>\n
\u201cThe crew was then unable to downlink the imagery from the Thermal Protection System (TPS) camera as planned. Troubleshooting was attempted, but discontinued for crew sleep.\u201d<\/p>\n
An issue has also been noted with Fuel Cell O2 Flowmeter measurement, which has failed Off Scale Low (OSL), which holds slight impacts to its monitoring and use. Discovery has had similar problems of the same nature during her previous flights, such as STS-116.<\/p>\n
\u201cThe Fuel Cell 3, s\/n 116, Oxygen Flowmeter Measurement Failed OSL at 075\/01:57:15 GMT,\u201d noted a report to the Mission Management Team (MMT) on L2. \u201cThe Loss of the FC 3 O2 FM is negligible impact to the crew and a slight impact to MOD\/EGIL (Electrical Generation and Illumination Engineer).<\/p>\n
\u201cEGIL will use other parameter such as pressure decays, purge line temperatures, and fuel cell performance to verify FC 3 purge.\u201d<\/p>\n
![\"a38\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/03\/a38.jpg\" "\\"a38\\"")
The most probable cause of the FC 3 O2 Flowmeter OSL reading is a failure of one or more electronic components within the circuitry installed in the flowmeter.<\/p>\n\u201cFailure analysis performed on previous flowmeters has identified a marginal design with overstressed, obsolete EEE components within the circuit.<\/p>\n
\u201cRedundancy: FC 3 Purge can be verified by cryo pressure decays, purge line temperatures, and fuel cell performance. The pressure decays also serve as an indication of gross reactant leakage.<\/p>\n
\u201cWith the loss of FC 3 O2 FM, the vehicle is in a stable configuration. The FC 3 O2 FM measurement has been inhibited in the vehicle Fault Detection Annunciation to avoid nuisance alarms. No additional on-orbit trouble shooting or analysis has been planned or is required.\u201d<\/p>\n
This particular Fuel Cell is on its last flight, due to its operating hours closing in on the time between overhaul limit. It is scheduled to be removed during post flight processing at the conclusion of STS-119.<\/p>\n
Other issues being reported to the MMT include the apparent loss of the Avionics Bay fan. No mission impacts have yet been noted on this particular issue. Another issue relates to the RMS shoulder brace release time, which is not deemed to have any mission impacts.<\/p>\n
L2 members<\/em><\/em>: 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":"
Discovery is completed her opening Thermal Protection System (TPS) inspections on Flight Day 2 of STS-119, as engineers on the ground evaluate ascent imagery and the opening \u2018funnies\u2019 reported to the Mission Evaluation Room (MER). In total, engineers have reported eight issues \u2013 all of which are minor and have no mission impact. Flight Day 2 opened […]<\/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":[9230,9191,9197,8715,9123,9231],"class_list":["post-41158","post","type-post","status-publish","format-standard","hentry","category-news","tag-fc","tag-fcv","tag-mmt","tag-obss","tag-sts-119","tag-wle-ids"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41158"}],"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=41158"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41158\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41158"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41158"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41158"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}