The Shuttle–Mir Program was a collaborative space program between Russia and the United States, which involved American Space Shuttles visiting the Russian space stationMir, Russian cosmonauts flying on the shuttle and American astronauts engaging in long-duration expeditions aboard Mir. The program, under the code name 'Phase One', was intended to allow the United States to learn from Russian experience into long-duration spaceflight and to foster a spirit of cooperation between the two nations and their respective space agencies, NASA and RKA, in preparation for further cooperative space ventures. Announced in 1993 with the first mission occurring in 1994, the program continued until its scheduled completion in 1998, and consisted of eleven shuttle missions, a joint Soyuz flight and almost 1000 days in space for American astronauts over seven expeditions. The program was, however, marred by various concerns, notably the safety of Mir following a fire and collision on board the station, financial issues with the cash-strapped Russian Space Program and worries from astronauts about the attitudes of the program administrators. Nevertheless, a large amount of science, expertise in space station construction and knowledge in working in a cooperative space venture was gained from the combined operations, allowing 'Phase Two' of the joint project, the construction of the International Space Station, to proceed much more smoothly than otherwise possible.