Aeronomy of Ice in the Mesosphere
The Aeronomy of Ice in the Mesosphere (AIM or Explorer 90) was a NASA satellite launched in 2007 to conduct a planned 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).
Source: Wikipedia — Aeronomy of Ice in the Mesosphere (CC BY-SA 4.0)