載人的人工結構物，在固定的軌道上運行的基地，作長期天文觀測、地球資源與環境研究、軍事偵查，以及無重力狀況下材料暨生物系統的研究。2001年時，在低地球軌道上安置有九座太空站，運作的時間長短不一。1971年蘇聯在地球軌道上設立世界第一座太空站禮炮1號（參閲Salyut）作為科學研究之用。從1974年至1982年，另外五座禮炮太空站成功進入軌道，兩座配備軍事偵查。1986年蘇聯發射和平號太空站的核心艙是科學用太空站，之後十年又擴充加入額外的五個艙。美國在1973年第一次發射太空站，稱為太空實驗室計畫，配備太陽觀測平台與醫學實驗室。1998年美國與俄羅斯開始在軌道上建造國際太空站，綜合實驗室與居住艙，最後至少有十六個國家參與。2000年國際太空站接受第一名常駐的工作人員。
space station
Manned artificial structure designed to revolve in a fixed orbit as a long-term base for astronomical observations, study of the earth's resources and environment, military reconnaissance, and investigations of materials and biological systems in weightless conditions. As of 2001, nine space stations have been placed in a low earth orbit and occupied for varying lengths of time. The Soviet Union orbited the world's first space station, Salyut 1 (see Salyut), designed for scientific studies, in 1971. From 1974 to 1982 five more Salyut stations—two outfitted for military reconnaissance—were successfully placed in orbit and occupied. In 1986 the U.S.S.R. launched the core module of Mir, a scientific station that was expanded with five additional modules over the next decade. The U.S. orbited its first space station in 1973; called Skylab, it was equipped as a solar observatory and medical laboratory. In 1998 the U.S. and Russia began the in-orbit construction of the International Space Station (ISS), a complex of laboratory and habitat modules that would ultimately involve contributions from at least 16 countries. In 2000 the ISS received its first resident crew.
