AEM (Application Explorer Missions) was a series of three Explorer spacecraft that investigated Earth and its environment. Each spacecraft had a name other than its AEM and Explorer designations. All of the subsystems used in the spacecraft were taken or modified from other programs such as IUE, IMP, RAE, and Nimbus. All the spacecraft could be launched into a range of orbits, from equatorial to polar, by Scout rockets. For more details, see HCMM (AEM-1, Explorer 58), SAGE (AEM-2, Explorer 60), and Magsat (AEM-3, Explorer 61).