$150 billion (total cost to date)
Orbiting the earth 15 times every day, the International Space Station continues to provide research in such fields as biology, physics, astronomy, and meteorology. The ISS currently consists of ten modules in low orbit traveling at approximately 17,000 miles per hour at an altitude of some 217 miles. Construction of the next four additional modules has been completed and each awaits their scheduled shipment between December 2008 and October of 2009. The latest addition, a Russian mini-research module, will be launched in March 2010.
The concept for this massive project was first conceived in the early 1990s, motivated to a large degree by the end of the space race between the United States and the Soviet Union. At that time a decision was made by the U.S. to begin negotiations that would lead to a Memorandum of Agreement between the space agencies of the U.S., Russia, Canada, Japan, and Europe (representing 11 European countries) for the construction of a space station that would be a truly international joint effort. The basic plan called for the construction of specifically designed modules by the U.S., European, Japanese, and Russian space agencies that would be launched and combined in orbit.
The First Module
The first module, one that provided electrical power, storage, propulsion, and guidance during initial assembly of the space station, was launched by Russia in November of 1998. This launch was quickly followed by a Space Shuttle delivery of the second module that December. This Boeing-made aluminum section provided six docking locations for other future modules and is the module that connects fluids, environmental controls and life support systems, and electrical and data systems to the work and living areas of the station. In July 2000 the so-called service module was placed into orbit by the Soviet Union providing the main living quarters for the crews, as well as providing the environmental systems, various electronic controls and additional docking ports.
With these three modules connected together the ISS was rendered inhabitable, a situation taken advantage of that November when two Russian cosmonauts and one American astronaut became the first crew members living in the ISS. It will eventually accommodate a six-member crew.
Between February 2001 and May 2008, seven additional modules were launched into orbit, six of them by the Space Shuttle. Also included was the robotic arm from Canada that handles large payloads, moves equipment and supplies around the station, supports astronauts working in space, etc. The remaining five modules will complete the ISS by 2010. From that point on the ISS will remain in operation until around 2016.