Stats: Atlas 5 and Delta 4 histories and backlogs (updated April 20)

The Atlas 5 rocket emerges Monday from the Vertical Integration Facility for rollout to Complex 41 at Cape Canaveral in preparation to launch the Orbital ATK Cygnus resupply ship to the International Space Station.

SpaceX’s next Falcon 9 rocket arrived at launch pad 39A Thursday for a customary hold-down engine firing. Liftoff from Florida’s Space Coast is targeted for Sunday, weather permitting.

DigitalGlobe’s WorldView 4 commercial satellite, which will join sister-craft WorldView 3 in orbit to snap the highest quality Earth imagery available on the market at 31-centimeter resolution, was built by Lockheed Martin and will be launched Friday atop an Atlas 5 rocket from Vandenberg Air Force Base, California.