Photos: Atlas 5 rocket soars from West Coast

Three rockets under the existing Block Buy between the Pentagon and United Launch Alliance have been assigned configurations and payloads.

A critical test firing Saturday of the four main engines powering the first stage of NASA’s gargantuan Space Launch System moon rocket is the final major hurdle before the fully assembled booster’s costly, oft-delayed launch late this year on an unpiloted test flight.

Launching the U.S. Navy’s fifth MUOS mobile communications satellite, a United Launch Alliance Atlas 5 rocket thundered away from Cape Canaveral today.