CAPE CANAVERAL, Fla. – At NASA's Kennedy Space Center, workers from NASA's Goddard Space Flight Center receive the Cosmic Origins Spectrograph, or COS, secured in its transportation canister, in the airlock of the Payload Hazardous Servicing Facility. 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

CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, STS-119 Mission Specialists Joseph Acaba, left, and Richard Arnold inspect hardware slated to fly on their upcoming space shuttle mission. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, STS-119 Commander Lee Archambault inspects hardware slated to fly on his upcoming space shuttle mission. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, the STS-119 crew takes time to familiarize themselves with hardware slated to fly on their upcoming space shuttle mission. From left are Pilot Tony Antonelli, Mission Specialist Richard Arnold, Commander Lee Archambault, and Mission Specialists Steve Swanson, Joseph Acaba and John Phillips. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - In the Space Station Processing Facility at NASA's Kennedy Space Center, STS-119 Mission Specialist Richard Arnold, assisted by Mission Specialist Joseph Acaba at right, gets some hands-on training with hardware slated to fly on his upcoming space shuttle mission. Mission Specialist Steve Swanson observes at left. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, from left, STS-119 Mission Specialists Steve Swanson, Richard Arnold and Joseph Acaba inspect hardware slated to fly on their upcoming space shuttle mission. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, from left, STS-119 Mission Specialist Richard Arnold, Commander Lee Archambault, and Mission Specialists John Phillips and Steve Swanson familiarize themselves with hardware slated to fly on their upcoming space shuttle mission. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett