Transcript: Space exploration is expensive, and space travel using humans is even more expensive. The high cost almost forces international cooperation. This started in the 1970s with the Apollo-Soyuz program. In the 1980s the United States developed the first reusable spacecraft, the space shuttle. The space shuttle was envisaged originally as something like a truck that could go into space forty or fifty times a year at a moderate cost. The reality has not been so happy. The space shuttle costs each flight fifty or a hundred times more than originally planned and has never gone up more than ten or twelve times a year. Two of the five space shuttles have been catastrophically lost with the astronauts on board. The Mir Space Station built by the Russians degraded so badly that it had to be abandoned. The International Space Station is now underway cooperatively between Europe, the United States, Russia, and Japan, but the cost is making all of those countries reconsider their involvement.