Workers roll into position in the clean room of the Payload Hazardous Servicing Facility for instrument testing and integration with the Flight Support System carrier.

At NASA's Kennedy Space Center, workers from NASA's Goddard Space Flight Center roll the Cosmic Origins Spectrograph, or COS, into position in the clean room of the Payload Hazardous Servicing Facility for instrument testing and integration with the Flight Support System carrier. The COS will be installed on the Hubble Space Telescope on space shuttle Atlantis' STS-125 mission. COS will be the most sensitive ultraviolet spectrograph ever flown on Hubble and will probe the "cosmic web" - the large-scale structure of the universe whose form is determined by the gravity of dark matter and is traced by galaxies and intergalactic gas. COS's far-ultraviolet channel has a sensitivity 30 times greater than that of previous spectroscopic instruments for the detection of extremely low light levels. Launch of STS-125 is targeted for Oct. 8. Photo credit: NASA/Jack Pfaller