13 April 2007: A spacecraft called the Aeronomy of Ice in the Mesosphere (AIM) will take flight from Vandenberg Air Force Base in California aboard a Pegasus launch vehicle. The AIM satellite is scheduled to launch on April 25. From AIM, scientists will begin a two-year study of “noctilucent” clouds.
Primarily composed of water ice, these silvery blue, iridescent clouds that shine brightly at night 50 miles above the earth’s surface were first observed in 1885 by scientist Robert Leslie after a volcanic eruption on the Indonesian island of Krakatoa. Since then, the clouds have been observed and noted on numerous missions. Scientists have noticed that these clouds are becoming brighter, occurring more frequently, and at lower latitudes.
Scientists believe that there may be a connection between the build up of carbon dioxide at the earth’s surface or “global warming” and an increase in frequency of ice clouds forming 50 miles above the earth’s surface. The buildup of carbon dioxide that causes a warming effect at the earth’s surface is believed to be causing a freezing effect above the earth. Scientists think this may be the reason we are seeing more noctilucent clouds.
By measuring Polar Mesospheric Clouds and the thermal, chemical and dynamical environment in which they form, the connection between these clouds and the meteorology of the polar mesosphere will be better understood. The study will help in understanding long-term variability in the mesospheric climate and its relationship to global change.
The AIM mission is comprised of three experiments: the Solar Occulation for Ice Experiment, the Cloud Imaging and Particle Size Experiment, and the Cosmic Dust Experiment. The mission is expected to provide insights into long term mesospheric changes.