The LOC included Launch Complex 39, a Launch Control Center, and a 130 million cubic foot (3.7 million cubic meter) Vertical Assembly Building (VAB) in which the space vehicle (launch vehicle and spacecraft) would be assembled on a Mobile Launcher Platform and then moved by a transporter to one of several launch pads. Although at least three pads were planned, only two, designated A and B, were completed in October 1965. The LOC also included an Operations and Checkout Building (OCB) to which Gemini and Apollo spacecraft were initially received prior to being mated to their launch vehicles. The Apollo spacecraft could be tested in two vacuum chambers capable of simulating atmospheric pressure at altitudes up to 250,000 feet (76 km), which is nearly a vacuum.