There are a number of sensor technologies that are currently matured and commercially available for vehicle health management (VHM) of aerospace systems. However, in a number of instances available sensors cannot survive, perform, or produce reliable data in the intended operational environment. For example, monitoring the integrity of the thermal protection systems (TPS) requires robust measurement capabilities, with extreme thermal and vibration survivability requirements. Similarly, in gas turbine engine environments rotating components, vibrations, oil, temperature, etc. create a hostile and difficult environment for sensor placement and reliable operation. This paper will focus on the technology readiness levels of various sensor technologies available for VHM of aerospace systems, which are a critical component of any VHM system.