If you would like to see more articles like this please support our coverage of the space program by becoming a Spaceflight Now Member. If everyone who enjoys our website helps fund it, we can expand and improve our coverage further. A Delta 4-Heavy rocket stands inside the mobile shelter on Space Launch Complex-6 at Vandenberg Air Force Base ahead of liftoff later this spring. Credit: United Launch Alliance United Launch Alliance recently raised a Delta 4-Heavy rocket, one of four left in the company’s backlog, vertical on its launch pad at Vandenberg Air Force Base in California in preparation for liftoff with a top secret U.S. government spy satellite at the end of April.