Watch the Falcon 9 launch from pad 39A

SpaceX test-fired the Crew Dragon spacecraft’s eight SuperDraco abort engines Wednesday at Cape Canaveral, paving the way for a high-altitude rocket escape test and demonstrating engineers have apparently fixed the problem that triggered an explosion during a similar ground firing in April.

These photographs span activities in March as the news media got an up-close viewing of the Orbital ATK commercial Cygnus cargo ship, its placement aboard a mobile transporter and delivery of the craft to the United Launch Alliance Atlas 5 rocket assembly building for hoisting and mating. Liftoff is scheduled for April 18.

SpaceX launched a classified payload for the National Reconnaissance Office on Monday after a first stage sensor problem halted a countdown Sunday. Liftoff from launch pad 39A at NASA’s Kennedy Space Center in Florida occurred at 7:15 a.m. EDT (1115 GMT), and the first stage landed at nearby Cape Canaveral around nine minutes later. The upper stage’s flight entered a pre-planned news blackout a few minutes after launch.