Space observatories are instruments deployed in outer space to study the universe beyond the limits of Earth's atmosphere. There are several different synonyms used to describe space observatories including astronomical observatories, space telescopes, and orbital observatories. Many of these synonyms are used interchangeably to describe instruments that are designed to study celestial objects, phenomena, and cosmic radiation. Other synonyms include satellite observatories, planetary observatories, and deep-space observatories. Some of the most well-known space observatories include the Hubble Space Telescope, Kepler Space Telescope, and the Chandra X-ray Observatory. Despite the different synonyms, these instruments all serve the same purpose of expanding our understanding of the universe.