Q&A with John Shannon, Boeing’s SLS vice president and program manager (members only)

The first of up to seven United Launch Alliance missions lifted off Jan. 19 from Vandenberg Air Force Base in California, where a Delta 4-Heavy launcher fired into orbit with 2.1 million pounds of thrust from three hydrogen-fueled RS-68A main engines with a U.S. government spy satellite.

United Launch Alliance’s Atlas 5 rocket, modified for crewed launches, rolled out of the Vertical Integration Facility Wednesday for the 1,800-foot trek to pad 41 in preparation for liftoff with Boeing’s Starliner crew capsule on an unpiloted mission to the International Space Station.

The next launch of a SpaceX Falcon Heavy rocket has been delayed from July to October to await the readiness of its U.S. military payload, and the following Falcon Heavy flight has been rescheduled from late this year to some time in 2022, military officials said.