An emitting structure for simulating an irradiance signature of a missile is provided. The emitting structure includes one or more radiation sources, each of which includes at least one ultraviolet radiation source and at least one infrared radiation source. The emitting structure also includes a spherical shell and a mechanism for positioning the radiation source(s) along a three dimensional boundary of the spherical shell. The emitting structure can locate and operate one of the radiation sources to simulate the irradiance signature of the missile.