A high performance, inexpensive, airborne simulator that will serve as the prototype for a small satellite based imaging system capable of mapping thermal anomalies on the surface of the earth with a high revisit rate and high spatial resolution is proposed. The Thermal Mapping Airborne Simulator for Small Satellite Sensor (TMAS) will be developed to a TRL 8 in the Phase II and the space-qualified system will be developed and built in Phase III. The proposed system will deliver high spatial resolution (133 urad), high signal to noise performance, three spectral bands, and onboard processing to extract the information of greatest value, orthorectify the imagery, and reduce the size of the data for transmission. This sensor system is designed to fit within the size, weight, and power (SWaP) envelopes of typical remote sensing aircraft and small satellites. The proposed design incorporates a step stare scanning mirror, a two band (LWIR 8 to 9 um and MWIR 4 5 um) Quantum Well Infrared Photodetector (QWIP), a short wave IR sensor (1.6 um), and an FPGA based image processing and orthorectification processing module.