International Space Station

A joint project of NASA, Roscosmos, ESA, JAXA, and CSA, the ISS has hosted continuous human habitation since 2 November 2000 and is the largest structure ever assembled in orbit at over 400,000 kilograms and the size of an American football field. It has served as a microgravity laboratory for more than 3,000 scientific experiments, advancing research in medicine, materials science, fundamental physics, and Earth observation across 25 years of uninterrupted operation.