1998

International Space Station

Early-twentieth-century rocket pioneers such as Konstantin Tsiolkovsky and Robert Goddard were among the first to work out the technical details of orbiting stations and habitats in space. For most of the century, however, the idea of a human outpost in Earth orbit was only realized in science fiction books, magazines, TV shows, and movies. In the 1970s the Soviet Union launched the first of nine long-duration Salyut space research modules, followed up in the 1980s by the orbital assembly of their Mir space station—the first long-duration, multicrew outpost in space.

NASA’s plans to launch a US space station (called Freedom) in the 1980s never materialized, due to cost overruns and technical delays. The fall of the Soviet Union in 1991, technical problems with the Mir station, and the high cost of launching and operating space vehicles in general all compelled NASA, Russia, and other space-faring nations to pool resources toward the design and operation of a joint International Space Station (ISS), begun in 1993.

The first component of the new ISS was a Russian electrical power, propulsion, and storage module called Zarya, launched into low Earth orbit (about 230 miles [370 kilometers] above the surface) on a Russian Proton rocket in November 1998. The second component, a US docking, airlock, and research module called Unity, was launched and connected to Zarya a few weeks later by the crew of the space shuttle Endeavour. Fifteen more launches of shuttles and Russian Proton and Progress rockets over the next 13 years added additional solar panels, living quarters, laboratories, airlocks, and docking ports. Completed in 2011, the ISS now spans the area of a US football field, with a total mass of more than 920,000 pounds (420,000 kilograms), making it the largest artificial satellite ever constructed. In addition to the United States and Russia, the European, Japanese, and Canadian space agencies are also key partners.

The ISS is primarily an international research laboratory designed to take advantage of its unique microgravity, orbital environment to enable space-related medical, engineering, and astrophysical research. But it also serves an important role as an outpost for a permanent human presence in space, a place where we can learn how to live and work there, and how best to prepare to venture further beyond low Earth orbit for deep space voyages of exploration.

The International Space Station orbits about 190 miles (305 kilometers) above Earth’s surface. Assembly of the space research outpost began in 1998; this 2009 photo taken by the crew of the space shuttle Discovery shows the station’s solar panels, trusses, and pressurized modules.