A Delta IV Heavy Launch Vehicle launches from Space Launch Complex-6 from Vandenberg Air Force Base. – Photo by Reuters.

This photo shows the Delta IV Heavy Launch Vehicle sits on the launch pad in preparation for its launch. – Photo by AP.

A Delta IV Heavy Launch Vehicle launches from Space Launch Complex-6. – Photo by Reuters.

A Boeing Delta IV Heavy rocket rises from the launch pad. – Photo by AP.

A Boeing Delta 4 Heavy rocket, which may someday be used to send humans into space, rises from the launch pad during its first unmanned launch. – Photo by AP.

A Boeing Delta 4 Heavy rocket, which may someday be used to send humans into space, rises from the launch pad during its first unmanned launch. – Photo by AP.