La NASA est\u00e1 retirando su \u00fanico telescopio espacial dedicado a la caza de asteroides, poniendo fin a una misi\u00f3n de 10 a\u00f1os que inicialmente comenz\u00f3 como algo completamente diferente: un explorador astrof\u00edsico destinado a abrir los ojos de los cient\u00edficos al universo infrarrojo. El telescopio NEOWISE de la NASA ha buscado asteroides, enanas marrones y galaxias luminosas. La nave espacial pronto se quemar\u00e1 en la atm\u00f3sfera de la Tierra.<\/p>\n
NASA is retiring its only dedicated asteroid-hunting space telescope, ending a 10-year mission that initially began as something else entirely: an astrophysics surveyor meant to open scientists\u2019 eyes to the infrared universe.<\/p>\n
The\u00a0telescope launched into Earth orbit as the Wide-Field Infrared Survey Explorer<\/a>\u00a0(WISE) in 2009, mapped the infrared skies for a year, then went into hibernation in early 2011 after running out of coolant. But in late 2013\u00a0NASA reawakened the spacecraft<\/a>, rechristened as Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE)\u2014a reference to its new quarry, asteroids with orbits that send them swooping within the general vicinity of our planet.<\/p>\n But not even a second lease on life was expected to let the remarkably productive telescope endure for this long. And even now NASA is only ending the NEOWISE mission because the spacecraft has sunk low enough in Earth\u2019s tenuous upper atmosphere that it will burn to pieces in just a few months. The telescope concludes its survey July 31; NASA will send final shutdown commands to the spacecraft on August 8.<\/p>\n \u201cI don\u2019t feel that it\u2019s really a big loss,\u201d says Edward Wright, an astronomer at the University of California, Los Angeles, who was principal investigator for the WISE mission. \u201cIt\u2019s been a very successful mission, so I\u2019m really happy with that…. The only thing that\u2019s causing our troubles is the atmosphere, and really, I can\u2019t complain about the atmosphere because I breathe it every day.\u201d<\/p>\n The WISE Era<\/b><\/p>\n In the 1990s Wright and his colleagues began discussing the telescope that would become WISE, inspired by improvements in infrared detectors. \u201cBasically, we said we want to find unique objects,\u201d Wright says. That\u2019s how WISE came to be a full-sky survey focused on infrared light, which has wavelengths longer than visible light and which permits scientists to peer through dust that can otherwise hide stars and galaxies from view.<\/p>\n Wright\u2019s wish list for the mission included two particular targets. He wanted to find the most luminous galaxy in the universe\u2014which the telescope did, spotting one shining as bright as 300 trillion suns. And he wanted to find the closest star to our sun, which he suspected would be a\u00a0brown dwarf<\/a>\u2014a faintly glowing gassy object several times larger than Jupiter yet still too small to fuse hydrogen to helium and shine as \u201ctrue\u201d stars do. Although the triple star system of\u00a0Alpha Centauri<\/a>\u00a0remains the sun\u2019s closest-known stellar neighbor, WISE did pin down a pair of brown dwarfs just 6.5 light-years from our solar system.<\/p>\n And even before its asteroid-hunting heyday, the WISE mission made a name for itself among planetary scientists just as much as astrophysicists. With its full powers, the spacecraft was able to peer into the main asteroid belt between Mars and Jupiter, observing more than 150,000 space rocks in this region of the solar system. \u201cIt was just a demon asteroid-finder,\u201d Wright says of the telescope during its primary mission.<\/p>\n In fact, it was during the telescope\u2019s WISE era that scientists on the project made what\u2019s still a favorite discovery of Amy Mainzer, a planetary scientist at the University of California, Los Angeles, and principal investigator for the NEOWISE mission. That discovery was of the first-ever\u00a0Trojan asteroid in Earth\u2019s orbit<\/a>. Trojan asteroids orbit the sun along the same path as a planet, either trailing behind or advancing ahead\u2014Jupiter boasts the largest posse of these rocks, with more than 13,000 of them, but other planets claim a handful as well. And Earth has one, too, WISE determined: a 1,000-foot-wide rock. \u201cI thought that was really cool,\u201d Mainzer says. \u201cIt turns out Earth has a little friend\u2014not so little, actually.\u201d<\/p>\n