Time-lapse: The Falcon 9 and Crew Dragon roll to the launch pad (members only)

NASA has declared assembly complete on the core stage for the first Space Launch System heavy-lift rocket in New Orleans, signaling a long-awaited transition from manufacturing to testing as the core stage is set to move to the nearby Stennis Space Center in Mississippi for a hold-down firing next year of its four shuttle-era main engines.

The Starlink 17-12 mission will send the two dozen broadband internet satellites into a polar, low Earth orbit. SpaceX is targeting liftoff from pad 4E at Vandenberg Space Force Base no earlier than Friday, Sept. 19, at 9:31 a.m. PDT (12:31 p.m. EDT / 1631 UTC).

SpaceX’s Falcon 9 rocket took off from Cape Canaveral on its 15th flight just before sunset Wednesday, putting on a spectacular sky show en route to space with a NOAA satellite to measure the solar wind.