Snapshots from Atlas 5 launch

The twin 177-foot-tall solid-fueled boosters for the first flight of NASA’s Space Launch System have been stacked inside the Vehicle Assembly Building at the Kennedy Space Center to await arrival of the rocket’s cryogenic core stage, which is set for a second engine test on a firing stand in Mississippi later this month.

NASA and SpaceX officials are moving forward with preparations to launch the next commercial Crew Dragon mission to the International Space Station next week after a Flight Readiness Review Thursday, pending a final evaluation of a discovery by SpaceX that it has potentially been loading slightly more propellant than expected into its Falcon 9 rockets.

Final preparations began this weekend at NASA’s Stennis Space Center in Mississippi to load super-cold liquid hydrogen and liquid oxygen into the massive core stage of the Space Launch System heavy-lift rocket for the first time as soon as Monday.