Science "CAREs" About Edge-of-Space Cloud Behavior Published Dec. 13, 2010 By Eva Blaylock Space Vehicles KIRTLAND AIR FORCE BASE, New Mexico -- In the interest of investigating the phenomena of noctilucent--or night-shining--clouds, Air Force Research Laboratory worked with other science community participants to assist the Naval Research Laboratory and Department of Defense Space Test Program in launching the Charged-Aerosol Release Experiment rocket. The spacecraft's successful launch from the National Aeronautics and Space Administration Wallops Flight Facility, Virginia, took place aboard a NASA four-stage Black Brant XII suborbital sounding rocket. For its part, AFRL collected measurements of the release using optical equipment deployed to Cape May, New Jersey, along with Global Positioning System and ultra-high-frequency receivers located at Martha's Vineyard and aboard a downrange boat. Although difficult to spot with the naked eye, naturally occurring noctilucent clouds are best visible just after sunset, when sunlight from below the horizon illuminates them. Also known as polar mesospheric clouds, noctilucents consist of ice crystals and are the highest clouds in the earth's atmosphere, tending to hover around 50 to 55 mi above the planet's surface. Released a bit higher than this (at about 173 mi altitude), the CARE rocket's exhaust particles will trigger an artificial cloud formation that simulates natural noctilucents and thus enables associated data collection. This experiment will not only help scientists gain insight into the formation, evolution, and properties of noctilucent clouds, but also assist their development and validation of simulation models for predicting the upper-atmospheric distribution of dust particles from rocket motors.