Cosmic Origins Spectrograph
Hubble ultraviolet spectrograph
The Cosmic Origins Spectrograph is Hubble's high-throughput ultraviolet spectrograph, optimized for faint point sources such as distant quasars and tenuous intergalactic gas. Separate far- and near-ultraviolet channels cover about 900 to 3200 angstroms. Medium-resolution gratings operate near resolving power 20,000, while low-resolution modes operate near 3,000. COS minimizes reflective surfaces in the far-ultraviolet optical path to preserve sensitivity and uses photon-counting detectors suited to weak ultraviolet signals. Astronauts installed it during STS-125.
Parent systems
The larger spacecraft or system this hardware belongs to.
Instrument dossier
Identity and integration
- Official designation
- Cosmic Origins Spectrograph (COS)
- Installed
- STS-125, May 2009
- Parent observatory
- Hubble Space Telescope
Science capability
- Far-ultraviolet coverage
- Approximately 900 to 2150 angstroms
- Near-ultraviolet coverage
- Approximately 1650 to 3200 angstroms
- Medium-resolution modes
- Resolving power near R 20,000
- Low-resolution modes
- Resolving power near R 3,000
- Science apertures
- Two circular apertures, each 2.5 arcseconds in diameter
- Sensitivity performance
- More than 30 times the STIS sensitivity for far-ultraviolet observations of faint point sources
Detector and optical systems
- Far-ultraviolet detector
- Photon-counting cross-delay-line detector
- Optical strategy
- Minimal-reflection far-ultraviolet light path for high throughput
Mechanical and electrical
- Instrument mass
- 850 pounds
- Instrument dimensions
- 0.9 x 0.9 x 2.2 meters
Installation and operations
- Installation operation
- Installed in an axial instrument bay during STS-125 after COSTAR was removed
Additional specifications
- Instrument class
- High-throughput ultraviolet spectrograph
- Replaced instrument
- Corrective Optics Space Telescope Axial Replacement
- Crew relationship
- Installed by the STS-125 servicing crew
Supported mission records
Missions that carried, used, tested, serviced, or depended on this hardware.
Photo Archive
Documented views of this individual vehicle, with source and credit retained alongside each image.