An employee walks out from the core stage of the Space Launch System, which will power the Artemis 1 lunar mission, as NASA Administrator Jim Bridenstinein tours the NASA Michaud Assembly Facility in New Orleans, Thursday, Aug. 15, 2019. (AP Photo/Gerald Herbert)

NASA's top official says the rocket expected to power the next mission to the moon is about 90 percent complete.

NASA administrator Jim Bridenstine spoke during a visit Thursday to a facility in New Orleans where the core stage is being built.

The 212-foot-tall (65-meter-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 in 2020.

Plans call for the rocket to carry a crewless Orion capsule in a double loop around the during 25½ days in flight.

Future missions are expected to carry U.S. astronauts, including the first female astronaut to land on the moon.

  • NASA Administrator Jim Bridenstine talks to reporters in front of the core stage of the Space Launch System, which will power the Artemis 1 lunar mission, as he visits the NASA Michaud Assembly Facility in New Orleans, Thursday, Aug. 15, 2019. (AP Photo/Gerald Herbert)

  • NASA Administrator Jim Bridenstine talks to reporters in front of the core stage of the Space Launch System, which will power the Artemis 1 lunar mission, as he visits the NASA Michaud Assembly Facility in New Orleans, Thursday, Aug. 15, 2019. (AP Photo/Gerald Herbert)

  • People walk in front of the core stage of the Space Launch System, which will power the Artemis 1 lunar mission, as NASA Administrator Jim Bridenstinein tours the NASA Michaud Assembly Facility in New Orleans, Thursday, Aug. 15, 2019. (AP Photo/Gerald Herbert)

  • NASA Administrator Jim Bridenstine talks to reporters in front of the core stage of the Space Launch System, which will power the Artemis 1 lunar mission, as he visits the NASA Michaud Assembly Facility in New Orleans, Thursday, Aug. 15, 2019. (AP Photo/Gerald Herbert)