SpaceX believes that vibrations caused a failure of a fuel line in the aft section of the upper stage (i.e., Starship, not its Super Heavy booster), leading to a fuel leak. Two minutes after separation and ignition of the upper stage engines, this leak also ignited. The leak and consequent fire were so significant that they exceeded Starship’s venting capacity, which is used to extinguish such fires. This raging fire dramatically increased the pressure in the aft section and began to compromise the rocket engines. After two minutes of this, these engines started to shut down automatically, which somehow led to communications loss to ground control (which really shouldn’t be the case). Three minutes after this loss of communication, Starship entered into a self-destruction sequence