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Space Telescope Imaging Spectrograph (STIS)

The Space Telescope Imaging Spectrograph (STIS) is a general-purpose spectrograph that spans ultraviolet, visible, and near-infrared wavelengths. It was installed in February 1997 during the Second Servicing Mission. A spectrograph works by breaking up light from an object into its individual wavelengths so that its composition, temperature, motion, and other chemical and physical properties can be analyzed. STIS stopped functioning in 2004 due to a power supply failure, but astronauts replaced a low-voltage power supply board during Servicing Mission 4.