On July 11 a SpaceX Falcon 9 rocket failed to reach its intended orbit resulting in the loss of 20 Starlink v2 mini satellites. This Loss Of Mission (LOM) follows a run of 325 successful Falcon 9 flights, hence a highly unusual occurrence for SpaceX. The company have a full manifest of high profile missions, so have requested permission from the FAA to continue launch operations. SpaceX suggest this ‘anomaly’ doesn’t pose any threat to public safety, and are currently waiting for a determination from the FAA. Quite aggressively, SpaceX want to launch 4 Starlink missions between July 19 and July 22, which seems optimistic as the FAA has yet to issue a waiver. If, for any reason, the FAA decide not to overlook this anomaly, ultimately this could still end up in the company’s favor.
Currently SpaceX are performing a thorough investigation to determine the root cause of the anomaly, with full oversight from federal authorities. Realistically the FAA could wait until this mishap investigation is complete, and review all the remedial actions, before making a determination on the vehicle’s safety. This suggests all Falcon 9 and Falcon Heavy missions will be delayed for the duration of this investigation, with some considerable impact on the company. However, as they say: “it’s always darkest before dawn” and the situation isn’t as dire as it first appears…
Prior experience
In June 2015, SpaceX’s CRS-7 mission for NASA suffered a similar LOM after the second stage exploded during ascent. NASA were fairly sanguine over the loss of this ISS cargo mission, they know launch failures happen all the time, particularly with relatively young space companies. However, the next morning they rang SpaceX to see if they needed any help starting the complex technical investigation. SpaceX were surprised by this offer and reported they had already spent 2,000 man-hours on the investigation, and thought they would be alright. Essentially every available engineer at SpaceX had been assigned to help, and many had worked through the night. Over the following weeks these engineers diligently identified all the possible causes of the explosion and constructed a fault tree, with these possible causes as its branches leading to the root failure. If any possible cause didn’t match the data received from the rocket, this allowed them to remove a branch from the fault tree, narrowing the possible suspects by a process of elimination.
Examining the telemetry closely, they discovered a high pitched ‘pop’ had been recorded just milliseconds before the stage exploded. Using data from accelerometers they managed to triangulate this sound to a strut that secured one of the helium bottles used to pressurize the stage. Given this evidence and the now denuded fault tree they determined the strut must have failed, causing the helium bottle to break free. This had fractured the attached pipework, releasing extremely high pressure helium into the propellant tank– like a bomb exploding... From that point on, SpaceX disregarded all supplier quality assurances and stress tested all components before final assembly, to ensure none would fail during flight. However, the other possible causes identified in the investigation were not forgotten, any risk they posed was either minimized or eliminated completely, considerably improving the vehicle’s overall safety. In addition, SpaceX took the opportunity to make many other improvements to the vehicle and support equipment, including the Autonomous Spaceport Drone Ship (ASDS).
Six months later SpaceX returned to flight with their new “Full Thrust” version of Falcon 9 and managed to perform the first booster landing at the Cape, in a momentous return to service. Essentially they had used the downtime to significantly improve Falcon 9 performance and reliability, allowed them to recover and reuse the first stage, which constitutes ~70% of the vehicle.
What to expect
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