Intelligent Fiber Optic Systems Corporation (IFOS) proposes an innovative fiber optic-based, multiplexable, highly ruggedized, integrated sensor system for real-time measurement and monitoring of temperature in an Ablative Thermal Protection System (TPS). Such measurement will allow for an effective estimation of temperature gradient and subsequent calculation of heat flux. IFOS will initially develop such a system for thermal monitoring in Small Probe applications. However, the technology will readily be applicable to other NASA vehicle applications where TPS is employed. The IFOS fiber optic sensors will incorporate Fiber Bragg Gratings (FBGs). These sensors are extremely light-weight, small, electromagnetically immune, and electrically passive. Multiple sensing FBGs can be fabricated on a single fiber for simplified design and reduced cost. The proposed fiber optic sensing technology is highly sensitive and accurate. It is also low-cost and lends itself to high-volume production. In the Phase I, IFOS will perform a feasibility study of its proposed temperature measurement and monitoring system.