Cosmic Origins Spectrograph

The Cosmic Origins Spectrograph (COS) is a science instrument that was installed on the Hubble Space Telescope during Servicing Mission 4 (STS-125) in May 2009. It is designed for ultraviolet (90–320 nm) spectroscopy of faint point sources with a resolving power of ≈1,550–24,000. Science goals include the study of the origins of large scale structure in the universe, the formation and evolution of galaxies, and the origin of stellar and planetary systems and the cold interstellar medium. COS was developed and built by the Center for Astrophysics and Space Astronomy (CASA-ARL) at the University of Colorado at Boulder and the Ball Aerospace and Technologies Corporation in Boulder, Colorado.

COS is installed into the axial instrument bay previously occupied by the Corrective Optics Space Telescope Axial Replacement (COSTAR) instrument, and is intended to complement the Space Telescope Imaging Spectrograph (STIS) that was repaired during the same mission. While STIS operates across a wider wavelength range, COS is many times more sensitive in the UV.^[1][2]