STS-120 was a space shuttle mission to the International Space Station (ISS) that launched on 23 October 2007 from the Kennedy Space Center, Florida. The mission is also referred to as ISS-10A by the ISS program. STS-120 delivered the Harmony module and reconfigured a portion of the station in preparation for future assembly missions. STS-120 was flown by Space Shuttle Discovery, and was the twenty-third space shuttle mission to the ISS.
The International Space Station programme is tied together by a complex set of legal, political and financial agreements between the sixteen nations involved in the project, governing ownership of the various components, rights to crewing and utilization, and responsibilities for crew rotation and resupply of the International Space Station. It was conceived in 1984 by President Ronald Reagan, during the Space Station Freedom project as it was originally called.