Stats: Delta 4 history and backlog (updated March 30)

SpaceX called off a Falcon 9 countdown Wednesday due to the threat of lightning from thunderstorms along Florida’s Space Coast, pushing back the departure of a cargo mission for the International Space Station until Thursday.

These are artist’s concepts and press conference briefing slides from the United Launch Alliance unveiling of its new Vulcan rocket to debut in 2019.

Payload readiness has delayed next weekend’s planned Delta 4-Heavy rocket launch for the U.S. National Reconnaissance Office.