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