SpaceX has confirmed that following the outcome of an investigation into how its Falcon 9 rocket exploded in September 2016 it will relaunch the craft on January 8.
For the past four months investigators, which included officials from the Federal Aviation Administration, the US Air Force , the National Aeronautics and Space Administration , the National Transportation Safety Board and several industry experts, scoured more than 3,000 channels of video and telemetry data covering a very brief timeline of events in order to establish what anomaly caused Falcon 9’s explosion in September.
The 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, leading to ignition and the subsequent failure of the COPV.
Falcon 9 uses COPVs to store cold helium which is used to maintain tank pressure, and each COPV consists of an aluminium inner liner with a carbon overwrap. The recovered COPVs showed buckles in their liners.
The accident investigation team worked systematically through an extensive fault tree analysis and concluded that one of the three composite overwrapped pressure vessels (COPVs) inside the second stage liquid oxygen (LOX) tank failed.
However, the team also identified several other credible causes for the COPV failure, all of which involve accumulation of super chilled LOX or SOX in buckles under the overwrap.
In response, SpaceX has put into place a number of corrective actions that address all credible causes and focus on changes which avoid the conditions that led to September’s explosion.
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.
In the long term, SpaceX will implement design changes to the COPVs to prevent buckles altogether, which will allow for faster loading operations.
The rocket that SpaceX plan to launch on January 8 will launch from Vandenberg’s Space Launch Complex 4E (SLC-4E) with the Iridium NEXT satellite aboard.