{"id":13936,"date":"2018-03-13T22:31:23","date_gmt":"2018-03-13T14:31:23","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/nasa-releases-summary-of-investigation-into-spacexs-2015-launch-failure\/"},"modified":"2018-03-13T22:31:23","modified_gmt":"2018-03-13T14:31:23","slug":"nasa-releases-summary-of-investigation-into-spacexs-2015-launch-failure","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/nasa-releases-summary-of-investigation-into-spacexs-2015-launch-failure\/","title":{"rendered":"NASA releases summary of investigation into SpaceX\u2019s 2015 launch failure"},"content":{"rendered":"<p><iframe loading=\"lazy\" width=\"678\" height=\"381\" src=\"https:\/\/www.youtube.com\/embed\/fTom8xVzFdo?feature=oembed\" frameborder=\"0\" allow=\"autoplay; encrypted-media\" allowfullscreen=\"\"><\/iframe><\/p>\n<p>NASA\u2019s independent review team that investigated the destruction of a SpaceX Falcon 9 rocket and Dragon supply ship shortly after liftoff in June 2015 concluded a design error led to the loss of more than two tons of provisions and equipment heading for the International Space Station.<\/p>\n<p>Engineers from NASA\u2019s Launch Services Program, a group based at the Kennedy Space Center in Florida, reviewed telemetry from the doomed flight and compiled an independent report on the launch failure. Under regulations set by the Federal Aviation Administration, the government agency which oversees commercial rocket launches by U.S. companies, SpaceX itself was in charge of the primary investigation team.<\/p>\n<p>The NASA review board largely agreed with SpaceX on the direct cause of the launch failure \u2014 the rupture of the Falcon 9\u2019s upper stage liquid oxygen tank triggered by a pressurized helium vessel that broke free in flight, according to a public summary of their report released Monday.<\/p>\n<p>But the agency\u2019s engineers faulted SpaceX for using a substandard steel component in a strut that was supposed to hold the helium reservoir inside the liquid oxygen tank, where propellant was chilled to near minus 300 degrees Fahrenheit (minus 184 degrees Celsius).<\/p>\n<p>The Falcon 9 rocket launched from Cape Canaveral on June 28, 2015, with SpaceX\u2019s seventh Dragon cargo mission to the space station. The launcher\u2019s first stage flew as planned until 2 minutes, 19 seconds, after liftoff, when a puff of vapor suddenly appeared near the top of the Falcon 9.<\/p>\n<p>Within 800 to 900 milliseconds from the first indication of a problem, the Falcon 9 began disintegrating at an altitude of nearly 150,000 feet \u2014 about 44 kilometers \u2014 over the Atlantic Ocean.<\/p>\n<p>\u201cIn other words, the vehicle went from flying fine to conflagration in less than a second, or \u2018within a blink of an eye,&#8217;\u201d NASA officials wrote in a summary of their inquiry published Monday.<\/p>\n<p>Within a few weeks of the launch failure, SpaceX officials publicly identified what the company\u2019s engineers determined was the most probable cause of the accident.<\/p>\n<p>SpaceX\u2019s engineers concluded a material defect in an axial support strut holding a helium-filled Composite Overwrapped Pressure Vessel, or COPV, caused the bracket to fracture under the structural loads of launch.<\/p>\n<p>The helium is used to pressurized the upper stage\u2019s propulsion system.<\/p>\n<p>\u201cThe strut that we believe failed was designed in material certified to handle 10,000 pounds of force, but actually failed at 2,000 pounds force, which is a five-fold difference,\u201d SpaceX chief executive Elon Musk told reporters in a briefing around three weeks after the launch accident.<\/p>\n<p>According to NASA\u2019s report summary, the agency\u2019s independent review team and the SpaceX-led investigation agreed it was credible that a threaded cast stainless steel eye bolt, or rod end, on the suspect strut broke under the stresses of launch, allowing the COPV to break free of its mounts. The buoyancy of the COPV, loaded with highly-pressurized helium, caused it to accelerate upward, where it struck the wall of the upper stage\u2019s liquid oxygen tank with great force, NASA officials wrote in a summary of the independent inquiry\u2019s conclusions.<\/p>\n<p>Musk said in 2015 that the strut came from a third-party vendor, which SpaceX has not publicly identified.<\/p>\n<p>But NASA\u2019s review of the launch failure touched on a broader range of potential \u201cinitiating causes\u201d of the accident than outlined in SpaceX\u2019s investigation report.<\/p>\n<p>Besides the material defect explanation of the strut failure favored by SpaceX, NASA engineers wrote that manufacturing damage of the rod end, the improper installation of the rod end strut, collateral damage to the rod end, or the breakage of some other part of the COPV\u2019s axial strut were equally credible initiating causes.<\/p>\n<figure id=\"attachment_31072\" aria-describedby=\"caption-attachment-31072\" style=\"width: 677px\" class=\"wp-caption alignnone\"><img fetchpriority=\"high\" decoding=\"async\" class=\"size-full wp-image-31072\" src=\"http:\/\/spaceflightnow.com\/wp-content\/uploads\/2018\/03\/copv_strut.jpg\" alt=\"\" width=\"677\" height=\"469\" srcset=\"https:\/\/spaceflightnow.com\/wp-content\/uploads\/2018\/03\/copv_strut.jpg 677w, https:\/\/spaceflightnow.com\/wp-content\/uploads\/2018\/03\/copv_strut-300x208.jpg 300w\" sizes=\"(max-width: 677px) 100vw, 677px\"><figcaption id=\"caption-attachment-31072\" class=\"wp-caption-text\">A diagram of a helium bottle, with its strut and rod end, inside the Falcon 9 upper stage liquid oxygen tank. Credit: NASA<\/figcaption><\/figure>\n<p>NASA also knocked SpaceX for not testing the rod end, which was not built to aerospace specifications, under the conditions the part would encounter during a launch.<\/p>\n<p>\u201cLastly, the key technical finding by the IRT with regard to this failure was that it was due to a design error: SpaceX chose to use an industrial grade (as opposed to aerospace grade) 17-4 PH SS (precipitation-hardening stainless steel) cast part (the \u201crod end\u201d) in a critical load path under cryogenic conditions and strenuous flight environments,\u201d NASA\u2019s report said.<\/p>\n<p>\u201cThe implementation was done without adequate screening or testing of the industrial grade part, without regard to the manufacturer\u2019s recommendations for a 4:1 factor of safety when using their industrial grade part in an application, and without proper modeling or adequate load testing of the part under predicted flight conditions.\u201d<\/p>\n<p>SpaceX stopped using the type of strut that failed in 2015 when flights resumed later that year with an upgraded \u201cfull thrust\u201d version of the Falcon 9, and NASA said all of its technical findings were addressed by SpaceX in time for the next Falcon 9 launch with one of the space agency\u2019s missions \u2014 the Jason 3 oceanography satellite \u2014 in January 2016.<\/p>\n<p>Another Falcon 9 rocket mishap in September 2016, when a booster exploded during a launch pad test and destroyed an Israeli-owned commercial telecom satellite, was also blamed on a problem with the upper stage\u2019s helium pressurant tanks.<\/p>\n<p>SpaceX engineers believe that failure started when liquid oxygen propellant froze in a buckle or void in a liner on one of the COPVs. The solid oxygen ignited from friction or breaking fibers on the outside of the helium tank, causing the Falcon 9\u2019s upper stage to burst in a ball of flame.<\/p>\n<p>SpaceX modified its fueling and helium loading procedures after the September 2016 accident to prevent solid oxygen from forming, and a new COPV design incorporates changes the company says eliminates the buckles altogether.<\/p>\n<p>SpaceX has accomplished 23 consecutive successful rocket launches since the Falcon 9 resumed service in January 2017.<\/p>\n<p><b><i>Email the author.<\/i><\/b><\/p>\n<p><em><strong>Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>NASA\u2019s independent review team that investigated the destruction of a SpaceX Falcon 9 rocket and Dragon supply ship shortly after liftoff in June 2015 concluded a design error led to the loss of more than two tons of provisions and equipment heading for the International Space Station. Engineers from NASA\u2019s Launch Services Program, a group [&hellip;]<\/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":[291,1395,479,717,1602,428,25,679],"class_list":["post-13936","post","type-post","status-publish","format-standard","hentry","category-news","tag-commercial-space","tag-dragon","tag-falcon-9","tag-international-space-station","tag-iss-cargo","tag-kennedy-space-center","tag-launch","tag-launch-services-program"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13936"}],"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=13936"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13936\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=13936"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=13936"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=13936"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}