Super Heavy booster used for the third Starship integrated flight test. It was lost to a hard water landing due to multiple Raptor engines failing to reignite.
Super Heavy booster used for the sixth Starship integrated flight test.
Lost to the ocean after a soft splashdown, as part of an offshore divert from the originally planned tower catch at the launch site.
First Super Heavy booster to complete a cryogenic proof test at the Orbital Launch Pad, as well as the first full stack cryogenic proof test for a Starship vehicle. Booster 4 is now on display at SpaceX's Rocket Garden in Boca Chica.