Space Launch Complex 4 (SLC-4) is a launch site at Vandenberg Air Force Base with two pads, both of which are used by SpaceX for Falcon 9 launch operations.The complex was previously used by Atlas and Titan rockets between 1963 and 2005. It consisted of two launch pads, SLC-4W and SLC-4E, which were formerly designated PALC2-3 and PALC2-4 respectively. Both pads were built for use by Atlas-Agena rockets, but were later rebuilt to handle Titan rockets.