A NASAspacecraft aimed at probing the mysteries of Earth's highest clouds is gearingup for launch.
The spaceagency's Aeronomy of Ice in the Mesosphere (AIM) satellite is counting down towardsan April 25 space shot to begin the first-ever mission dedicated to trackingEarth's odd noctilucent- or 'night shining' - clouds.
First observedin 1885, the clouds - also known as polar mesospheric clouds (PMC) - are madeof ice crystals hovering some 50 miles (80 kilometers) above Earth. They are onlyvisible at night when they reflect sunlight after the Sun has dipped belowthe planet's horizon.
In recentyears, the previously rare clouds have been found to shine brighter, occur morefrequently and appear at lower latitudes than ever before, leading somescientists to speculate that their behavior may be related to global climatechanges, such as global warming, said Vicki Elsbernd, NASA's AIM mission programexecutive at the agency's Washington, D.C. headquarters, during a Wednesdaybriefing.
Built forNASA by Orbital Sciences and overseen by researchers at Hampton University inHampton, Virginia, the $140million AIM spacecraft is slated to rocket spaceward at 4:26:49 p.m. EDT (2026:49GMT) on April 25 atop an air-launched Pegasus XL rocket. About the size of a smallpiano, the 430-pound (195-kilogram) spacecraft will depart from California'sVandenberg Air Force Base on a two-year mission.
"Othersatellite missions have made measurements of these clouds, but they weren'toptimized and it was not their intent in the beginning," AIM principalinvestigator Jim Russell, of Hampton University, told reporters Wednesday. "Theyprovided information, but not enough to really address the fundamental questionof why [the clouds] form and how they vary."
Because similarcloud formations are seen high above the surface of Mars, researchers hope tobetter understand their implications for life on Earth and future missions tothe red planet, Elsbernd added.
"We're veryexcited about the AIM launch," Elsbernd said. "We expect that the new discoveriesfrom AIM, along with our other great observatory missions, will literally rewritethe textbooks in our understanding of Sun and its effects on the Earth's atmosphereand on the solar system."
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