Photos: X-37B gallery archive

A United Launch Alliance Atlas 5 rocket, flying in its basic two-stage configuration with no strap-on solids, was stacked aboard a mobile launch platform at Cape Canaveral’s Vertical Integration Facility on Feb. 22 and 23 in preparation to send Orbital ATK’s S.S. John Glenn cargo ship into orbit for the International Space Station.

Using a new, uprated main engine for the first time on a rocket of its kind, a United Launch Alliance Delta 4-Medium+ vehicle will soar into space Wednesday night carrying a $566 million Air Force communications satellite.

SpaceX and United Launch Alliance have split up to $645 million in new contracts to deploy U.S. Air Force navigation and surveillance satellites into orbit from 2019 through 2021.