Photos: Delta 4 awaits blastoff

SpaceX is replacing two engines on the Falcon 9 booster set to launch four astronauts next month on the company’s first operational Crew Dragon flight to the International Space Station, following an investigation that revealed a subcontractor failed to adequately clean out narrow vent ports on multiple engines across the company’s fleet, officials said Wednesday.

A United Launch Alliance Atlas 5 rocket blasted off from Cape Canaveral at 8:38 a.m. EST (1338 GMT) Friday to place the Global Positioning System 2F-12 navigation satellite into space. Follow the mission in our live journal.

A commercial communications satellite will blast off Thursday from French Guiana on top of a Soyuz rocket, on the way to a station over the Americas to supply bandwidth to airline travelers and broadcasters in the United States, Canada and Mexico.