May 16, 2009
Astronauts Complete Toughest Repair Job Yet
Mission Specialists John Grunsfeld and Andrew Feustel completed the third spacewalk of Atlantis' mission to the Hubble Space Telescope in 6 hours and 36 minutes, stepping smoothly through the difficult tasks of repairing a delicate camera and installing its most sensitive spectrograph ever.
Grunsfeld and Feustel began the spacewalk at 8:35 a.m., removing the telescope's16-year-old "contact lens," the Corrective Optics Space Telescope Axial Replacement (COSTAR), and safely tucked it into the shuttle's payload bay. The two then installed the new Cosmic Origins Spectrograph (COS), which will allow Hubble to peer farther into the universe than ever before in the near and far ultraviolet ranges.
The successfully installed $88 million spectrograph is designed to detect faint light from faraway quasars. They made room for the gadget by removing the corrective lenses that restored Hubble's vision in 1993.
"This is really pretty historic," Grunsfeld said as he and Feustel hoisted out the phone booth-size box containing Hubble's old contacts.
This addition to the Hubble is expected to provide greater insight into how planets, stars and galaxies formed.
Later in the mission, Grunsfeld and Feustel used specially designed tools to carry out a job that was never intended to do during a spacewalk, repairing the Advanced Camera for Surveys (ACS). The camera, known for some of the most famous imagery captured by Hubble, had stopped working in early 2007 when its backup power supply short-circuited. The two removed 32 screws from an access panel to efficiently replace the camera's four circuit boards and install a new power supply.
"This activity is dedicated to studying the behavior of tiny screws in space," he joked.
Grunfeld carefully opened up the burned-out camera and pulled out each of the four electronic cards that needed to be replaced.
"Somehow I don't think brain surgeons go 'woo-hoo' when they pull something out," one of the astronauts observed from inside Atlantis.
The new cards and power supply pack fit the 19-year-old observatory perfectly, seeming like it took no time at all. The astronauts even found themselves running ahead of schedule.
In a test conducted from the Space Telescope Operations Control Center at Goddard Space Flight Center in Greenbelt, Md., engineers powered up the 851-pound COS to make sure its power and data connection were operating. While the astronauts sleep, the team will conduct additional functional tests on each component to determine if the astronauts will need to perform additional work. The COS will be calibrated over the next several weeks.
The spacewalk was the 80th in space shuttle history. Grunsfeld now ranks fourth among all spacewalkers, with 51 hours and 28 minutes to his credit over seven excursions.
Tomorrow, astronauts Michael Good and Mike Massimino will repair the Space Telescope Imaging and Spectrograph (STIS) and install the New Outer Blanket Layer (NOBL).
The crew's sleep period will begin at 8:31 p.m. will wake at 4:31 a.m. tomorrow. The next status report will be issued tomorrow morning or earlier, if events warrant.
If everything goes according to plan, the last spacewalk is set for Monday, while the telescope is to be released from Atlantis on Tuesday.
This mission to the Hubble cost over $1 billion.
Image Credit: NASA-----------
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