International Space Station program out of 28 flights have not been to the ISS, and only the planned Hubble Space Telescope servicing mission in 2009 will not be ISS-related out of 13 planned missions until the end of the Space Shuttle program in 2010). The Space Shuttle was retired from service upon the conclusion of Atlantis' final flight on July 21, 2011. NASA was reliant even at the time on some of the resupply contracts being fielded out to Soyuz and Progress and the other unmanned tugs, but it had launched a few years earlier into a program of aggressive development of commercial US
Space Shuttle program launched on September 29, 1988. The longest Shuttle mission was STS-80 lasting 17 days, 15 hours. The final flight of the Space Shuttle program was STS-135 on July 8, 2011. Since the Shuttle's retirement in 2011, many of its original duties are performed by an assortment of government and private vessels. The European ATV Automated Transfer Vehicle supplied the ISS between 2008 and 2015. Classified military missions are being flown by the US Air Force's unmanned space plane, the X-37B. By 2012, cargo to the International Space Station was already being delivered commercially under NASA's Commercial Resupply Services by SpaceX's