{"id":14971,"date":"2017-01-02T21:12:59","date_gmt":"2017-01-02T13:12:59","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/spacex-failure-probe-complete-flights-to-resume-sunday-from-california\/"},"modified":"2017-01-02T21:12:59","modified_gmt":"2017-01-02T13:12:59","slug":"spacex-failure-probe-complete-flights-to-resume-sunday-from-california","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/spacex-failure-probe-complete-flights-to-resume-sunday-from-california\/","title":{"rendered":"SpaceX failure probe complete; flights to resume Sunday from California"},"content":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION<\/p>\n

\"\"
File photo. Credit: NASA<\/figcaption><\/figure>\n

After an exhaustive investigation, SpaceX engineers have identified the most likely cause of the spectacular explosion of a Falcon 9 rocket during a pre-launch test Sept. 1 that destroyed the booster and its $195 million satellite payload, the company announced Monday.<\/p>\n

SpaceX engineers believe the Cape Canaveral Air Force Station mishap was triggered by the failure of a high-pressure helium tank, one of three used to pressurize the second stage liquid oxygen tank.<\/p>\n

Putting corrective actions in place, the company said Monday it plans to resume flights with a launch from Vandenberg Air Force Base northwest of Los Angeles on Jan. 8 to boost 10 Iridium NEXT satellite telephone relay stations into orbit.<\/p>\n

It is not yet known when SpaceX plans to resume flights from Cape Canaveral. Launch complex 40 at the Florida Air Force station was heavily damaged in the Sept. 1 mishap, and the company plans to use a repurposed space shuttle launch pad at the nearby Kennedy Space Center for its next Falcon 9 flight from Florida.<\/p>\n

Sources indicate the first flight from Kennedy will be another commercial mission. The next SpaceX flight to deliver cargo to the International Space Station, the company\u2019s 10th under contract to NASA, is expected to take place some time after the commercial mission.<\/p>\n

SpaceX\u2019s Falcon 9 rocket uses super-cooled, or \u201cdensified,\u201d liquid oxygen and RP-1 kerosene fuel to provide additional performance during ascent. To achieve and maintain the desired low temperatures, propellant loading begins just 35 minutes before launch.<\/p>\n

To push propellants to the rocket\u2019s engines, the Falcon 9 uses highly pressurized helium stored in aluminum bottles, wrapped in a tough, insulating carbon composite material. The bottles, known as composite overwrap pressure vessels, or COPVs, are mounted inside the propellant tanks, submerged in frigid liquid oxygen and chilled kerosene.<\/p>\n

On Sept. 1, about five minutes before a planned test firing of the Falcon\u2019s nine Merlin 1D first stage engines \u2014 a routine pre-launch test for SpaceX \u2014 the second stage suddenly exploded in a spectacular conflagration that was caught on video and widely seen around the world.<\/p>\n

The rocket and it\u2019s $195 million payload, a commercial communications satellite, were destroyed, causing heavy damage to launch complex 40 at the Cape Canaveral Air Force Station. Just 93 milliseconds elapsed from the first signs of trouble to the explosion.<\/p>\n

\u201cInvestigators scoured more than 3,000 channels of video and telemetry data covering a very brief timeline of events,\u201d SpaceX said in a statement posted to its website. \u201cBecause the failure occurred on the ground, investigators were also able to review umbilical data, ground-based video, and physical debris.<\/p>\n

\u201cTo validate investigation analysis and findings, SpaceX conducted a wide range of tests at its facilities in Hawthorne, California and McGregor, Texas.\u201d<\/p>\n

SpaceX is generally tight-lipped when it comes to technical details, and the statement posted Monday provided only a general overview of the team\u2019s findings. It said accident investigators \u201cconcluded that one of the three composite overwrapped pressure vessels (COPVs) inside the second stage liquid oxygen (LOX) tank failed.\u201d<\/p>\n

\u201cSpecifically, the investigation team concluded the failure was likely due to the accumulation of oxygen between the COPV liner and overwrap in a void or a buckle in the liner,\u201d the company said.<\/p>\n

Investigators believe those extremely low temperatures may have caused some of that trapped oxygen to solidify. In any case, when the tank was pressurized, trapped oxygen pushing against the carbon overwrap fibers likely generated friction \u201cleading to ignition and the subsequent failure of the COPV.\u201d<\/p>\n

Liquid oxygen has a temperature of around minus 298 degrees Fahrenheit, but SpaceX chills the propellant to around minus 340 degrees for use aboard the Falcon 9. The RP-1 kerosene fuel, which normally is stored at a room temperature 70 degrees, also is chilled. The lower temperatures increase the propellants\u2019 density.<\/p>\n

A rocket engine\u2019s thrust is directly proportional to the rate propellants are consumed and expelled. By \u201cdensifying\u201d the Falcon 9 propellants, more fuel can be stored and pumped through the engines, increasing performance.<\/p>\n

While earlier rockets, including the Titan 2 booster used to launch NASA\u2019s Gemini spacecraft in the 1960s, used propellant cooling to increase density, and thus engine performance, the upgraded Falcon 9 is believed to be the first utilizing super-cooled cryogenic oxygen.<\/p>\n

SpaceX founder Elon Musk said in 2015, when propellant cooling was first implemented in the Falcon 9, that \u201cwe\u2019re sub-cooling the propellant, particularly the liquid oxygen, close to its freezing point, which increases the density quite significantly.\u201d<\/p>\n

Failure investigators \u201cidentified several credible causes for the COPV failure, all of which involve accumulation of super chilled LOX or SOX (solidified oxygen) in buckles under the overwrap,\u201d the company said in its statement.<\/p>\n

\u201cThe corrective actions address all credible causes and focus on changes which avoid the conditions that led to these credible causes. In the short term, this entails changing the COPV configuration to allow warmer temperature helium to be loaded, as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads.\u201d<\/p>\n

The company did not provide any details about those earlier helium loading procedures but said it plans to redesign the helium bottles in the long term \u201cto prevent buckles altogether, which will allow for faster loading operations.\u201d<\/p>\n

The Sept. 1 failure was the second involving the Falcon 9\u2019s second-stage helium pressurization system.<\/p>\n

During a June 2015 launch to deliver supplies to the space station, a strut holding a second-stage helium tank in place inside the liquid oxygen tank failed, allowing the helium bottle to shoot up and crash into the top of the oxygen tank, triggering a catastrophic rupture.<\/p>\n

It was SpaceX\u2019s first outright Falcon 9 failure in 19 launchings dating back to the rocket\u2019s maiden flight in June 2010. After taking steps to ensure all internal struts met design specifications, SpaceX launched nine successful missions in a row before the Sept. 1 launch pad disaster, all of them using densified propellants.<\/p>\n","protected":false},"excerpt":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION File photo. Credit: NASA After an exhaustive investigation, SpaceX engineers have identified the most likely cause of the spectacular explosion of a Falcon 9 rocket during a pre-launch test Sept. 1 that destroyed the booster and its $195 million satellite payload, the company announced Monday. SpaceX engineers believe […]<\/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":[3143,479,530,2193,3269,2899,1574,316],"class_list":["post-14971","post","type-post","status-publish","format-standard","hentry","category-news","tag-amos-6","tag-falcon-9","tag-iridium","tag-iridium-next","tag-iridium-next-mission-1","tag-orbital-atk","tag-space-launch-complex-4-east","tag-spacex"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14971"}],"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=14971"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14971\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=14971"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=14971"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=14971"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}