Caelum Incognitum — The interactive encyclopedia of ufology
PAN (unidentified aerospace phenomenon)
Classifications & scales
Term used by GEIPAN, the French space agency CNES’s investigation unit, in place of “UFO”. Cases are rated A to D: A (certain explanation), B (probable explanation), C (no conclusion possible for lack of data) and D (reliable data, yet the phenomenon remains unexplained after in-depth investigation). D cases are a small minority of the total.