PREFIRE (Polar Radiant Energy in the Far InfraRed Experiment) Auxiliary Satellite Data for PREFIRE Satellite 2 contains data fields extracted from external satellite datasets for each coincident PREFIRE Thermal Infrared Spectrometer (TIRS-PREFIRE) field of view, which is then used to process PREFIRE Level 2 and 3 products. Dual CubeSats each carry a TIRS-PREFIRE, a push broom spectrometer with 63 channels measuring mid- and far-infrared (FIR) radiation from approximately 5 to 53 µm. Most polar emissions are in the FIR but have not been measured on a large scale. PREFIRE aims to fill knowledge gaps in the global energy budget by more accurately characterizing polar emissions. This information will then be assimilated into global circulation and other models to predict future conditions more accurately.This collection contains surface-type information from VIIRS, Aqua, and NISE (SSMIS). Its primary purpose is to provide surface type information for the PREFIRE Level 2 spectral flux product (PREFIRE_SAT1_2B-FLX) and the Level 3 surface emissivity product (PREFIRE_SAT1_3-SFC-SORTED-ALLSKY), which is sorted by surface type. Science data retrieval started July 24, 2024 and is ongoing. Geographic coverage is global, with the greatest concentration of data in the polar regions. Within the orbital swath there are eight distinct tracks of data associated with the eight separate spatial scenes for each PREFIRE-TIRS. At the beginning of the mission, the approximate scene footprint sizes were 11.8 km x 34.8 km (cross-track x along-track), with gaps between each scene of approximately 24.2 km. The entire swath was ~264 km across. Note that the scene footprint and swath sizes quoted here are for the orbit altitude soon after launch. However, the footprint size will slowly become smaller as the orbit altitude decreases with time. This data has a temporal resolution of 0.707 seconds and is available in netCDF-4.The auxiliary satellite data for the sister instrument aboard PREFIRE-SAT2 can be found in the PREFIRE_SAT2_AUX-SAT collection.