SpaceX is investigating a malfunction with the Falcon 9 rocket’s upper stage that caused it to reenter the atmosphere and fall into the sea outside its intended disposal area after a successful launch of the Crew Dragon spacecraft carrying NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov to the International Space Station. The upper stage’s Merlin vacuum engine underperformed during its deorbit burn, leading to an off-course reentry. This incident marks the third grounding of Falcon 9 in three months, following a similar issue in July.