{"678927":{"#nid":"678927","#data":{"type":"news","title":"NEOWISE, the NASA Mission That Cataloged Objects Around Earth for Over a Decade, Has Come to an\u00a0End","body":[{"value":"\u003Cdiv class=\u0022theconversation-article-body\u0022\u003E\u003Cp\u003EThe NASA project NEOWISE, which has given astronomers a detailed view of near-Earth objects \u2013 some of which could strike the Earth \u2013 ended its mission and burned on reentering the atmosphere after over a decade.\u003C\/p\u003E\u003Cp\u003EOn a clear night, the sky is full of bright objects \u2013 from stars, large planets and galaxies to tiny asteroids flying near Earth. These asteroids are commonly known as \u003Ca href=\u0022https:\/\/www.unoosa.org\/oosa\/sk\/ourwork\/topics\/neos\/index.html\u0022\u003Enear-Earth objects\u003C\/a\u003E, and they come in a wide variety of sizes. Some are tens of kilometers across or larger, while others are only tens of meters or smaller.\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/www.rmg.co.uk\/stories\/topics\/near-earth-objects-neos-near-misses\u0022\u003EOn occasion, near-Earth objects smash into Earth\u003C\/a\u003E at a high speed \u2013 roughly 10 miles per second (16 kilometers per second) or faster. That\u2019s about 15 times as fast as a rifle\u2019s muzzle speed. An impact at that speed can easily damage the planet\u2019s surface and anything on it.\u003C\/p\u003E\u003Cp\u003EImpacts from large near-Earth objects are generally rare over a typical human lifetime. But they\u2019re more frequent on a geological timescale of millions to billions of years. The best example may be a 6-mile-wide (10-kilometer-wide) asteroid that crashed into Earth, killed the dinosaurs and created Chicxulub crater \u003Ca href=\u0022https:\/\/doi.org\/10.1126\/science.208.4448.1095\u0022\u003Eabout 65 million years ago\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003ESmaller impacts are very common on Earth, as there are more small near-Earth objects. An international community effort called \u003Ca href=\u0022https:\/\/www.space.com\/planetary-defense-explained\u0022\u003Eplanetary defense\u003C\/a\u003E protects humans from these space intruders by cataloging and monitoring as many near-Earth objects as possible, including those closely approaching Earth. Researchers call the near-Earth objects \u003Ca href=\u0022https:\/\/theconversation.com\/nasa-is-crashing-a-spacecraft-into-an-asteroid-to-test-a-plan-that-could-one-day-save-earth-from-catastrophe-190888\u0022\u003Ethat could collide\u003C\/a\u003E with the surface \u003Ca href=\u0022https:\/\/cneos.jpl.nasa.gov\/about\/neo_groups.html\u0022\u003Epotentially hazardous objects\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/doi.org\/10.1088\/0004-637X\/743\/2\/156\u0022\u003ENASA began its NEOWISE mission\u003C\/a\u003E in December 2013. This mission\u2019s primary focus was to use the space telescope from the \u003Ca href=\u0022https:\/\/www.jpl.nasa.gov\/missions\/wide-field-infrared-survey-explorer-wise\/\u0022\u003EWide-field Infrared Survey Explorer\u003C\/a\u003E to closely detect and characterize near-Earth objects such as asteroids and comets.\u003C\/p\u003E\u003Cp\u003ENEOWISE contributed to planetary defense efforts with its research to catalog near-Earth objects. Over the past decade, it helped \u003Ca href=\u0022https:\/\/ae.gatech.edu\/directory\/person\/masatoshi-toshi-hirabayashi\u0022\u003Eplanetary defenders\u003C\/a\u003E \u003Ca href=\u0022https:\/\/www.astro.umd.edu\/people\/ykim1231.html\u0022\u003Elike us\u003C\/a\u003E and our colleagues study near-Earth objects.\u003C\/p\u003E\u003Ch2\u003EDetecting near-Earth objects\u003C\/h2\u003E\u003Cp\u003ENEOWISE was a game-changing mission, as it revolutionized how to survey near-Earth objects.\u003C\/p\u003E\u003Cp\u003EThe NEOWISE mission \u003Ca href=\u0022https:\/\/doi.org\/10.1088\/0004-6256\/140\/6\/1868\u0022\u003Econtinued to use the spacecraft\u003C\/a\u003E from \u003Ca href=\u0022https:\/\/science.nasa.gov\/mission\/neowise\/\u0022\u003ENASA\u2019s WISE mission\u003C\/a\u003E, which ran from late 2009 to 2011 and conducted an \u003Ca href=\u0022https:\/\/wise2.ipac.caltech.edu\/docs\/release\/allsky\/\u0022\u003Eall-sky infrared survey\u003C\/a\u003E to detect not only near-Earth objects but also distant objects such as galaxies.\u003C\/p\u003E\u003Cp\u003EThe spacecraft orbited Earth from north to south, passing over the poles, and it was in \u003Ca href=\u0022https:\/\/www.esa.int\/Enabling_Support\/Space_Transportation\/Types_of_orbits#SSO\u0022\u003Ea Sun-synchronous orbit\u003C\/a\u003E, where it could see the Sun in the same direction over time. This position allowed it to scan all of the sky efficiently.\u003C\/p\u003E\u003Cp\u003EThe spacecraft could survey astronomical and planetary objects by detecting the signatures they emitted in the mid-infrared range.\u003C\/p\u003E\u003Cp\u003EHumans\u2019 eyes can \u003Ca href=\u0022https:\/\/science.nasa.gov\/ems\/09_visiblelight\/\u0022\u003Esense visible light\u003C\/a\u003E, which is electromagnetic radiation between 400 and 700 nanometers. When we look at stars in the sky with the naked eye, we see their visible light components.\u003C\/p\u003E\u003Cp\u003EHowever, \u003Ca href=\u0022https:\/\/www.icc.dur.ac.uk\/%7Ett\/Lectures\/Galaxies\/Images\/Infrared\/Regions\/irregions.html\u0022\u003Emid-infrared light\u003C\/a\u003E contains waves between 3 and 30 micrometers and is invisible to human eyes.\u003C\/p\u003E\u003Cp\u003EWhen heated, an object stores that heat as thermal energy. Unless the object is thermally insulated, it releases that energy continuously as electromagnetic energy, in the mid-infrared range.\u003C\/p\u003E\u003Cp\u003EThis process, known as \u003Ca href=\u0022https:\/\/www.britannica.com\/science\/thermal-radiation\u0022\u003Ethermal emission\u003C\/a\u003E, happens to near-Earth objects after the Sun heats them up. The smaller an asteroid, the fainter its thermal emission. The NEOWISE spacecraft could sense thermal emissions from near-Earth objects at a high level of sensitivity \u2013 meaning it could detect small asteroids.\u003C\/p\u003E\u003Cp\u003EBut asteroids aren\u2019t the only objects that emit heat. The spacecraft\u2019s sensors could pick up heat emissions from other sources too \u2013 including the spacecraft itself.\u003C\/p\u003E\u003Cp\u003ETo make sure heat from the spacecraft wasn\u2019t hindering the search, the WISE\/NEOWISE spacecraft was designed so that it could actively cool itself using then-state-of-the-art \u003Ca href=\u0022https:\/\/doi.org\/10.1088\/0004-637X\/743\/2\/156\u0022\u003Esolid hydrogen cryogenic cooling systems\u003C\/a\u003E.\u003C\/p\u003E\u003Ch2\u003EOperation phases\u003C\/h2\u003E\u003Cp\u003ESince the spacecraft\u2019s equipment needed to be very sensitive to detect faraway objects for WISE, it used solid hydrogen, which is extremely cold, to cool itself down and avoid any noise that could mess with the instruments\u2019 sensitivity. Eventually the coolant ran out, but not until WISE had successfully completed its science goals.\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/doi.org\/10.1088\/0004-6256\/140\/6\/1868\u0022\u003EDuring the cryogenic phase\u003C\/a\u003E when it was actively cooling itself, the spacecraft operated at a temperature of about -447 degrees Fahrenheit (-266 degrees Celsius), slightly higher than the universe\u2019s temperature, which is about -454 degrees Fahrenheit (-270 degrees Celsius).\u003C\/p\u003E\u003Cp\u003EThe cryogenic phase lasted from 2009 to 2011, until the spacecraft went into hibernation in 2011.\u003C\/p\u003E\u003Cp\u003EFollowing the hibernation period, NASA decided to reactivate the WISE spacecraft under the NEOWISE mission, with a more specialized focus on detecting near-Earth objects, which was still feasible even without the cryogenic cooling.\u003C\/p\u003E\u003Cp\u003EDuring this \u003Ca href=\u0022https:\/\/doi.org\/10.1088\/0004-637X\/743\/2\/156\u0022\u003Ereactivation phase\u003C\/a\u003E, the detectors didn\u2019t need to be quite as sensitive, nor the spacecraft kept as cold as it was during the cryogenic cooling phase, since near-Earth objects are closer than WISE\u2019s faraway targets.\u003C\/p\u003E\u003Cp\u003EThe consequence of losing the active cooling was that two long-wave detectors out of the four on board became so hot that they could no longer function, limiting the craft\u2019s capability.\u003C\/p\u003E\u003Cp\u003ENevertheless, NEOWISE used its two operational detectors to continuously monitor both previously and newly detected near-Earth \u003Ca href=\u0022https:\/\/doi.org\/10.3847\/PSJ\/ac15fb\u0022\u003Eobjects in detail\u003C\/a\u003E.\u003C\/p\u003E\u003Ch2\u003ENEOWISE\u2019s legacy\u003C\/h2\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/science.nasa.gov\/mission\/neowise\/\u0022\u003EAs of February 2024\u003C\/a\u003E, NEOWISE had taken more than 1.5 million infrared measurements of about 44,000 different objects in the solar system. These included about 1,600 discoveries of near-Earth objects. NEOWISE also provided detailed size estimates for more than 1,800 near-Earth objects.\u003C\/p\u003E\u003Cp\u003EDespite the mission\u2019s contributions to science and planetary defense, it was decommissioned in August 2024. The spacecraft eventually started to fall toward Earth\u2019s surface, until it reentered Earth\u2019s atmosphere and burned up on Nov. 1, 2024.\u003C\/p\u003E\u003Cp\u003ENEOWISE\u2019s contributions to hunting near-Earth objects gave scientists much deeper insights into the asteroids around Earth. It also gave scientists a better idea of what challenges they\u2019ll need to overcome to detect faint objects.\u003C\/p\u003E\u003Cp\u003ESo, did NEOWISE find all the near-Earth objects? The answer is no. Most scientists still believe that there are far more near-Earth objects out there that still need to be identified, particularly smaller ones.\u003C\/p\u003E\u003Cp\u003ETo carry on NEOWISE\u2019s legacy, NASA is planning a mission called \u003Ca href=\u0022https:\/\/science.nasa.gov\/mission\/neo-surveyor\/\u0022\u003ENEO Surveyor\u003C\/a\u003E. \u003Ca href=\u0022https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ad0468\/meta\u0022\u003ENEO Surveyor\u003C\/a\u003E will be a next-generation space telescope that can study small near-Earth asteroids in more detail, mainly to contribute to NASA\u2019s planetary defense efforts. It will identify hundreds of thousands of near-Earth objects that are as small as about 33 feet (10 meters) across. The spacecraft\u2019s launch is scheduled for 2027.\u003C!-- Below is The Conversation\u0027s page counter tag. 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More info: https:\/\/theconversation.com\/republishing-guidelines --\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis article is republished from \u003C\/em\u003E\u003Ca href=\u0022https:\/\/theconversation.com\u0022\u003E\u003Cem\u003EThe Conversation\u003C\/em\u003E\u003C\/a\u003E\u003Cem\u003E under a Creative Commons license. Read the \u003C\/em\u003E\u003Ca href=\u0022https:\/\/theconversation.com\/neowise-the-nasa-mission-that-cataloged-objects-around-earth-for-over-a-decade-has-come-to-an-end-237921\u0022\u003E\u003Cem\u003Eoriginal article\u003C\/em\u003E\u003C\/a\u003E\u003Cem\u003E.\u003C\/em\u003E\u003C\/p\u003E\u003C\/div\u003E","summary":"","format":"full_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EThe NASA project NEOWISE, which has given astronomers a detailed view of near-Earth objects \u2013 some of which could strike the Earth \u2013 ended its mission and burned on reentering the atmosphere after over a decade.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"The NASA project NEOWISE, which has given astronomers a detailed view of near-Earth objects \u2013 some of which could strike the Earth \u2013 ended its mission and burned on reentering the atmosphere after over a decade."}],"uid":"27469","created_gmt":"2024-12-17 18:53:15","changed_gmt":"2024-12-17 18:57:56","author":"Kristen Bailey","boilerplate_text":"","field_publication":"","field_article_url":"","location":"Atlanta, GA","dateline":{"date":"2024-12-03T00:00:00-05:00","iso_date":"2024-12-03T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"675877":{"id":"675877","type":"image","title":" WISE, NEOWISE\u2019s predecessor mission, imaged the entire sky in the mid-infrared range. NASA\/JPL\/Caltech\/UCLA","body":"\u003Cdiv\u003E\u003Cp\u003EWISE, NEOWISE\u2019s predecessor mission, imaged the entire sky in the mid-infrared range. \u003Ca href=\u0022https:\/\/science.nasa.gov\/mission\/neowise\/\u0022\u003ENASA\/JPL\/Caltech\/UCLA\u003C\/a\u003E\u003C\/p\u003E\u003C\/div\u003E","created":"1734461777","gmt_created":"2024-12-17 18:56:17","changed":"1734461777","gmt_changed":"2024-12-17 18:56:17","alt":" WISE, NEOWISE\u2019s predecessor mission, imaged the entire sky in the mid-infrared range. NASA\/JPL\/Caltech\/UCLA","file":{"fid":"259551","name":"file-20241122-17-69o6oy.png","image_path":"\/sites\/default\/files\/2024\/12\/17\/file-20241122-17-69o6oy.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2024\/12\/17\/file-20241122-17-69o6oy.png","mime":"image\/png","size":1395778,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2024\/12\/17\/file-20241122-17-69o6oy.png?itok=In3Dpmpq"}}},"media_ids":["675877"],"related_links":[{"url":"https:\/\/theconversation.com\/neowise-the-nasa-mission-that-cataloged-objects-around-earth-for-over-a-decade-has-come-to-an-end-237921","title":"Read This Story on The Conversation"}],"groups":[{"id":"660364","name":"Aerospace Engineering"},{"id":"1214","name":"News Room"},{"id":"1188","name":"Research Horizons"}],"categories":[],"keywords":[],"core_research_areas":[],"news_room_topics":[{"id":"71911","name":"Earth and Environment"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Ch5\u003EAuthors:\u003C\/h5\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/theconversation.com\/profiles\/toshi-hirabayashi-1647682\u0022\u003EToshi Hirabayashi\u003C\/a\u003E, Associate Professor of Aerospace Engineering, \u003Ca href=\u0022https:\/\/theconversation.com\/institutions\/georgia-institute-of-technology-1310\u0022\u003E\u003Cem\u003EGeorgia Institute of Technology\u003C\/em\u003E\u003C\/a\u003E and \u003Ca href=\u0022https:\/\/theconversation.com\/profiles\/yaeji-kim-2259743\u0022\u003EYaeji Kim\u003C\/a\u003E, Postdoctoral Associate in Astronomy, \u003Ca href=\u0022https:\/\/theconversation.com\/institutions\/university-of-maryland-1347\u0022\u003E\u003Cem\u003EUniversity of Maryland\u003C\/em\u003E\u003C\/a\u003E\u003C\/p\u003E\u003Ch5\u003EMedia Contact:\u003C\/h5\u003E\u003Cp\u003EShelley Wunder-Smith\u003Cbr\u003E\u003Ca href=\u0022mailto:shelley.wunder-smith@research.gatech.edu\u0022\u003Eshelley.wunder-smith@research.gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}