Four months after a fueling accident led to the loss of a Falcon 9 rocket and its satellite payload, SpaceX said Monday morning that it has concluded an investigation into the incident and submitted its findings to the Federal Aviation Administration. The company also announced a target date of January 8th for a return to flight.
The SpaceX investigation, in concert with the FAA, US Air Force, NASA, and the National Transportation Safety Board, concluded that one of three composite overwrapped pressure vessels, or COPVs, inside the rocket's second stage liquid oxygen tank failed. "Specifically, 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, leading to ignition and the subsequent failure of the COPV," the company stated in an update.
COPVs are used in rocketry to contain high pressure fluids and offer a substantial weight savings over all-metal tank designs. In a general sense, a composite simply means a matrix of carbon fibers contained within a resin, which is then wrapped over a pressure barrier. The Falcon 9 rocket uses COPVs that consist of a carbon wrap over an aluminum liner to store cold helium, which in turn is used to maintain tank pressure.