Nasa’s top official says the rocket expected to power the next mission to the moon is about 90% complete.
Nasa administrator Jim Bridenstine spoke during a visit to a facility in New Orleans where the core stage is being built.
The 212-foot-tall core stage is made up of two liquid propellant tanks and four RS-25 engines.
In the months to come, the engine section will be attached to the rest of the core section. If all goes well, it will power the Artemis 1 test flight in 2020.
Plans call for the rocket to carry a crewless Orion capsule in a double loop around the moon during 25-and-a-half days in flight.
Future missions are expected to carry US astronauts, including the first female astronaut to land on the moon.