Mission
WISE surveyed the sky in four wavelengths of the infrared band, at a very high sensitivity. Its detector arrays have 5-sigma sensitivity limits of 120, 160, 650, and 2600 microjanskies (µJy) at 3.3, 4.7, 12, and 23 micrometres (aka microns). This is a factor of 1,000 times better sensitivity than the survey completed in 1983 by the IRAS satellite in the 12 and 23 micrometres (micron) bands, and a factor of 500,000 times better than the 1990s survey by the Cosmic Background Explorer (COBE) satellite at 3.3 and 4.7 micrometres. On the other hand, IRAS could also observe 60 and 100 micron wavelengths.
- Band 1 – 3.4 micrometres (microns) – broad-band sensitivity to stars and galaxies
- Band 2 – 4.6 micrometres – detect thermal radiation from the internal heat sources of sub-stellar objects like brown dwarfs
- Band 3 – 12 micrometres – detect thermal radiation from asteroids
- Band 4 – 22 micrometres – sensitivity to dust in star-forming regions (material with temperatures of 70–100 kelvins)
The primary mission lasts ten months: one month for checkout, six months for a full-sky survey, then an additional three months of survey until cryogenic coolant runs out. The partial second survey pass will facilitate the study of changes (e.g. orbital movement) in observed objects.
Read more about this topic: Wide-field Infrared Survey Explorer
Famous quotes containing the word mission:
“Not in vain is Ireland pouring itself all over the earth. Divine Providence has a mission for her children to fulfill; though a mission unrecognized by political economists. There is ever a moral balance preserved in the universe, like the vibrations of the pendulum. The Irish, with their glowing hearts and reverent credulity, are needed in this cold age of intellect and skepticism.”
—Lydia M. Child (1802–1880)
“When you’re dealing with monkeys, you’ve got to expect some wrenches.”
—Alvah Bessie, Ranald MacDougall, and Lester Cole. Raoul Walsh. Captain Nelson, Objective Burma, giving a subaltern a mission (1945)
“We can come up with a working definition of life, which is what we did for the Viking mission to Mars. We said we could think in terms of a large molecule made up of carbon compounds that can replicate, or make copies of itself, and metabolize food and energy. So that’s the thought: macrocolecule, metabolism, replication.”
—Cyril Ponnamperuma (b. 1923)