The NASA Administrator appeared at the space agency’s Michoud Assembly Facility in New Orleans, Louisiana, where the 212ft rocket is being assembled.
Once completed, the rocket will be sent to NASA’s Stennis Space Center near Bay St Louis, Mississippi.
Mr Bridenstine said: “The completion of the SLS core stage is a major milestone and a testament to American enterprise and ingenuity.
“With more than 1,100 large and small businesses in 44 states contributing to the design and assembly, the SLS rocket will empower America to achieve the Artemis program’s goal of landing the first woman and next man on the Moon by 2024.”
