The Falcon 9 is grounded pending an investigation, possibly delaying upcoming crew flights. //

"Upper stage restart to raise perigee resulted in an engine RUD for reasons currently unknown," Musk wrote in an update two hours after the launch. RUD (rapid unscheduled disassembly) is a term of art in rocketry that usually signifies a catastrophic or explosive failure. //

Going into Thursday's mission, the current version of SpaceX's Falcon 9 rocket, known as the Falcon 9 Block 5, was indisputably the most reliable launch vehicle in history. Since debuting in May 2018, the Falcon 9 Block 5, which NASA has certified for astronaut flights, never had a mission failure in all of its 297 launches before the ill-fated Starlink 9-3 mission. //

The Falcon 9's only total in-flight launch failure occurred on its 19th flight on June 28, 2015, when the upper stage's liquid oxygen tank burst a couple of minutes after launch from Cape Canaveral Space Force Station, Florida. The rocket disintegrated in the upper atmosphere, dooming a Dragon cargo capsule en route to the space station.

SpaceX resumed Falcon 9 launches six months later in December 2015. On that flight, SpaceX landed the Falcon 9's first stage booster back at Cape Canaveral for the first time, a historic achievement and a harbinger of the company's later success in reusing rockets. //

SpaceX's Falcon family of rockets, which counted 335 consecutive successful launches since the on-pad explosion in 2016, or 344 flights since an in-flight failure. Both numbers are all-time industry records.