 As the International Space Station modules design began in the early 1990s, KSC began to work with other NASA centers and international partners to prepare for processing before launch on board the Space Shuttles.KSC utilized its hands-on experience processing the 22 Spacelab missions in the Operations and Checkout Building to gather expectations of ISS processing.These experiences were incorporated into the design of the Space Station Processing Facility (SSPF), which began construction in 1991.