What is the name of the Hubble spectrograph installed in 2009?

The Cosmic Origins Spectrograph was installed on Hubble in 2009. Astronauts fitted COS during Servicing Mission 4, the final Hubble servicing mission, which was carried out by Space Shuttle Atlantis in May 2009.

COS is an ultraviolet spectrograph designed to examine faint, compact targets such as stars and quasars. Instead of producing a conventional picture, it spreads incoming light into a spectrum, allowing astronomers to measure the fingerprints of atoms and molecules, including material between galaxies.

The instrument covers far-ultraviolet wavelengths from about 90 to 205 nanometers and near-ultraviolet wavelengths from roughly 170 to 320 nanometers. Its design emphasizes high sensitivity, making it particularly valuable for studying very faint objects.

Space Telescope Imaging Spectrograph, another option, is also a Hubble spectrograph, which makes it an understandable distractor. However, STIS was originally installed in 1997 and was repaired during the 2009 mission; COS was the new spectrograph installed that year. COS occupied the axial bay formerly used by COSTAR.