Photos: Atlas 5 rocket soars from West Coast

Virgin Orbit could attempt its first orbital test launch later this month over the Pacific Ocean southwest of Los Angeles, capping a development program for an air-launched small satellite carrier that began in earnest eight years ago.

The fifth and final satellite for the U.S. Navy’s new mobile network to provide rugged smartphone communications to all branches of the military has arrived at the launch site for blastoff in May.

A critical test-firing of the Space Launch System’s core stage engines cut off about a minute into a planned eight-minute burn Saturday on a test stand at NASA’s Stennis Space Center in Mississippi. The rocket’s four engines ignited at 5:27 p.m. EST (2227 GMT) for a test that was to pave the way for the core stage’s shipment to the Kennedy Space Center for launch preparations.