Snapshots from Atlas 5 launch

The head of NASA’s human spaceflight programs has abruptly resigned, announcing his departure from the space agency two days before before he was to chair a crucial readiness review ahead of the launch of the first crewed U.S. space mission in nearly a decade.

A replay of the United Launch Alliance Atlas 5 rocket launching the classified NROL-55 payload for the National Reconnaissance Office from Vandenberg Air Force Base, California.

United Launch Alliance and Boeing teams worked through the weekend on closeouts of the Starliner crew capsule, inspections and final outfitting of the Atlas 5 rocket. A launch readiness review Tuesday approved the continuation of final preparations for liftoff from Cape Canaveral Friday of the first Starliner spacecraft on an unpiloted test flight to the International Space Station.