Live coverage: Atlas 5 countdown and launch journal

The change will allow the U.S. Space Force to expedite the process of building out its GPS constellation in medium Earth orbit. The launch date for the next satellite, GPS III Space Vehicle 09, could be within weeks.

A rocket engine that could power United Launch Alliance’s next-generation rocket has passed a major design review, clearing the way for full-scale hotfire testing starting next year and certification for test flights in 2019, according to Aerojet Rocketdyne, the powerplant’s developer.

United Launch Alliance called off a launch attempt Monday after hitting a snag during preparations to fill an Atlas 5 rocket with cryogenic propellants at Cape Canaveral, delaying the liftoff of a new U.S. Space Force infrared surveillance satellite until no earlier than Tuesday.