The International Space Station weighs almost 400 tonnes and covers an area as big as a football pitch. It would have been impossible to build the Space Station on Earth and then launch it into space in one go - there is no rocket big enough or powerful enough. To get round this problem the Space Station was taken into space piece-by-piece and gradually built in orbit, approximately 400 km above the Earth's surface. This assembly required more than 40 missions.

A partnership between European countries (represented by ESA), the United States (NASA), Japan (JAXA), Canada (CSA) and Russia (Roscosmos), the International Space Station is the world's largest international cooperative programme in science and technology.

In the following list the Space Station assembly flights are coded with a number and a letter: A stands for America, R for Russian, E for European and J for Japanese. UL is 'Utilisation Flight', LF means 'Logistics Flight' and ULF is an abbreviation from 'Utilisation and Logistics Flight'.