After a three day delay, NASA's Wide-field Infrared Survey Explorer this morning blasted into space courtesy of a Delta II rocket and will soon begin bathing the cosmos with infrared light, picking up the glow of hundreds of millions of objects and producing millions of images.
The space agency says the WISE spacecraft will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The idea behind the spacecraft is to uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets.
WISE will also scan for near-Earth objects, such as asteroids and comets, with orbits that come close to crossing Earth's path. The mission is expected to find hundreds of these bodies, and hundreds of thousands of additional asteroids in our solar system's main asteroid belt, NASA stated. By measuring the objects' infrared light, astronomers will get the first good estimate of the size distribution of the asteroid population. This information will tell us approximately how often Earth can expect an encounter with a potentially hazardous asteroid, NASA said.
The idea of getting a better handle on near-Earth asteroids could ease some concerns that NASA had been missing some of these occurrences. A National Academy of Sciences report earlier this year said that while Congress mandated four years ago that NASA detect and track 90% of space rocks known as near earth objects (NEO) 140 kilometer in diameter or larger, it has not authorized any funds to build additional observatories, either in space or on the ground, to help NASA achieve its goals.
WISE’s infrared telescope and detectors are kept chilled inside a Thermos-like tank of solid hydrogen, called a cryostat. This prevents WISE from picking up the heat, or infrared, signature of its own instrument. The solid hydrogen, called a cryogen, is expected to last about 10 months and will keep the WISE telescope at a minus 429 degrees Fahrenheit, NASA stated.
After a one-month checkout period, WISE will spend six months mapping the whole sky. It will then begin a second scan to uncover even more objects and to look for any changes in the sky that might have occurred since the first survey, according to NASA. This second partial sky survey will end about three months later when the spacecraft's frozen-hydrogen cryogen runs out. Data from the mission will be released to the astronomical community in two stages: a preliminary release will take place six months after the end of the survey, or about 16 months after launch, and a final release is scheduled for 17 months after the end of the survey, or about 27 months after launch.
WISE will join two other infrared missions in space -- NASA's Spitzer Space Telescope and the Herschel Space Observatory, a European Space Agency mission with important NASA participation. WISE is different from these missions in that it will survey the entire sky, NASA stated.