Aug 3 2005
From The Space Library
Space Shuttle Discovery astronauts Soichi Noguchi and Stephen K. Robinson completed a final spacewalk during which Robinson performed an unprecedented maneuver to complete a critical operation of the orbiter's thermal protection system. The principle objective of the spacewalk was to remove two pieces of protruding heat shielding~called gap fillers~from the bottom of the orbiter. NASA was concerned that the fillers might add extra heat to the orbiter's heat-shielding tiles upon reentry into Earth's atmosphere, thereby threatening the mission. Astronauts James M. Kelly and Wendy B. Lawrence used the robotic arms of the Shuttle and those of the ISS to lower Robinson to the underside of Discovery, while Noguchi monitored the operation. Despite concerns that Robinson might lose communication with the other astronauts, the operation was a success. The maneuver was the first time that an astronaut had worked on the underside of an orbiter while in space. During the spacewalk, Noguchi and Robinson also installed an external stowage platform and a new iteration of an experiment to test materials in the environment of space. (NASA, “NASA's Spacewalking Astronaut Completes Unique Repair,” news release 05-212, 3 August 2005; NASA, “Space Shuttle Mission Archives: STS-114,” http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/archives/STS-114.html (accessed 24 June 2009).)
Astronomers using NASA's Spitzer Space Telescope (SST) detected, for the first time, a large population of black holes known as type-2 quasars. Quasars~supermassive black holes~are the universe's brightest objects. Although scientists had observed the light from type-1 quasars, they had never before been able to detect type-2 quasars because, despite the brightness of type-2 quasars, the gas and dust rings that surround them obscure the quasars' visible light and block their emission of x-rays. Space telescopes and other scientific instruments rely on x-ray emissions to detect and to analyze these celestial phenomena. However, Alejo Martínez- Sansigre of the University of Oxford led a team of astronomers who used the SST to detect infrared light emitted by type-2 quasars, thereby capturing evidence of 2 1 quasars. The research also indicated that the growth of black holes has been concentrated in obscure regions of the universe and has tended to occur in the cores of forming galaxies during brief, highly productive periods. The new data suggested that thousands more such quasars might exist in the universe. (NASA, “NASA's Spitzer Finds Hidden, Hungry Black Holes,” news release 05-211, 3 August 2005; Alejo Martínez-Sansigre et al., “The Obscuration by Dust of Most of the Growth of Supermassive Black Holes,” Nature 463, no. 7051 (4 August 2005): 666-669.)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
