AIM-Aeronomy of Ice in the Mesosphere

The Aeronomy of Ice in the Mesosphere (AIM) satellite mission is exploring Polar Mesospheric Clouds (PMCs), also called noctilucent clouds, to find out why they form and why they are changing.

The AIM mission has been extended by NASA through the end of FY12. During this time the instruments will monitor noctilucent clouds to better understand their variability and possible connection to climate change. Individual instrument data collection status, as well as spacecraft and instrument health, will be monitored throughout the life of the mission and reported periodically

The Aeronomy of Ice in the Mesosphere (AIM) is a satellite to conduct a 26-month study of noctilucent clouds (NLCs). It is ninetieth Explorer program mission and is part of the NASA-funded Small Explorer program (SMEX). On April 25, 2007 AIM was boosted into a 600 km (370 mi) high polar orbit by a Pegasus-XL rocket, which was air-launched from the Lockheed L-1011 Stargazer aircraft operated by Orbital Sciences.

The noctilucent clouds AIM is to study, also known as polar mesospheric clouds, occur in the Earth's atmosphere at altitudes of roughly 80 kilometers (50 mi) above the surface, far higher than other clouds. The AIM mission will help determine what factors — temperature, water vapor, and dust particles — lead to the formation of these clouds. The clouds seem to be a relatively recent phenomenon: they were first seen in 1885, and lately seem to be occurring more frequently.