COSTAR—Corrective Optics Space Telescope Axial Replacement. The instrument placed inside the Hubble Space Telescope to correct the flaw in the telescope’s primary mirror.
deploy—To move an object, such as a satellite, into position.
Faint-Object Camera—Unique camera aboard the Hubble Space Telescope that takes pictures of exceptionally faint objects too dim to be seen by telescopes on Earth. It was developed by the European Space Agency, an important contributor to the telescope project.
Goddard High-Resolution Spectrograph—Instrument aboard the Hubble Space Telescope that analyzes ultraviolet light from glowing objects in space.
guidance system—The system aboard the Hubble Space Telescope that points it in the direction scientists wish to view.
gyroscope—A spinning device used to stabilize vehicles such as boats, planes, or spacecraft. They are an important part of the Hubble Space Telescope’s guidance system.
High-Speed Photometer—Instrument aboard the Hubble Space Telescope that can measure the size or magnitude of a star and its distance from Earth.
light-year—A measure of distance used by astronomers. Light travels at 186,000 miles per second, covering a distance of 5.9 trillion miles in one year. Therefore, 5.9 trillion miles equals one light-year.
optical telescope assembly—The central component of the Hubble Space Telescope, consisting of the primary and secondary mirror construction.
payload bay—The area of the space shuttle where cargo is stored.
Remote Manipulator System—The robotic arm in the payload bay of the space shuttle. It is controlled from the rear of the shuttle’s flight deck and was a major tool in the repair of the Hubble Space Telescope.
solar array—Silicon panels that use light from the sun to generate electrical power. The Hubble Space Telescope is powered by two solar arrays.
spectrograph—An instrument that divides light rays or other forms of radiation into a spectrum and then records that spectrum.
spherical aberration—Defect in the curvature of an optical mirror, preventing light from being focused into a single point.
ultraviolet—A part of the light spectrum that is invisible to human eyes. Most ultraviolet light from space is absorbed by Earth’s atmosphere.
Wide Field Planetary Camera—Camera aboard the Hubble Space Telescope that takes pictures of wider areas of the sky than the Faint-Object Camera. It can also narrow its field of vision to take detailed pictures of nearby objects such as planets, asteroids, and comets.