Live coverage: Delta 4 countdown and launch journal

Meet the Vulcan, the next-generation rocket family brought to you by United Launch Alliance that comes with a bold reusability plan, multiple configurations for medium- to heavy-lift, all-American engines and serves as the eventual replacement for the historic Atlas and Delta rocket lines.

A nuclear blast detection satellite and an assortment of experiments will be boosted directly into geosynchronous orbit 22,300 miles above Earth in 2019 by the most-powerful version of United Launch Alliance’s Atlas 5 rocket, the Air Force has decided.

A SpaceX Falcon 9 rocket fired its nine first stage engines for a brief hold-down firing Friday at Cape Canaveral, passing a key milestone before launch July 24 with a Dragon space station resupply ship.