Falcon 9 booster B1048 was a reusable orbital-class Block 5 Falcon 9 first-stage booster manufactured by SpaceX. B1048 was the third Falcon 9 Block 5 to fly and the second Block 5 booster to re-fly. It became the second orbital-class booster to fly a third time and is the first booster ever to be launched five times. B1048 service came to an end on its fifth flight when an engine shut down prematurely on launch. Whilst the primary mission was unaffected and the Starlink payload deployed successfully, B1048 was unable to land. In a subsequent investigation, SpaceX found that isopropyl alcohol, used as cleaning fluid, was trapped and ignited causing the engine to be shut down. To address the issue, in a following launch SpaceX indicated that the cleaning process was not done.