This proposal describes the development of passive surface acoustic wave (SAW) sensors and multi-sensor systems for NASA application to remote wireless sensing of temperature and pressure distributions in space vehicles and demanding environments. SAW devices are a mature technology used in numerous commercial wireless communication applications, satellites, and military systems. Research into the use of SAW devices as solid-state physical sensors is a relatively recent development, with potential emerging applications such as automotive tire pressure sensing. Much of the work reported has focused on single sensor devices and systems, with little work done on dense multi-sensor systems. The system proposed herein consists of multiple passive solid-state SAW sensors that can be interrogated remotely using RF signals, and that respond with a signal that encodes both the sensor's identity as well as measurements of temperature and pressure. The proposed research will study several innovative aspects of SAW sensor technology, including: new piezoelectric materials which can operate over large temperature ranges; new SAW device embodiments for measurement of temperature and pressure and their wireless transmission in multi-sensor environments; transceiver design and optimization given the SAW operating parameters; and innovative packaging and antenna considerations for rugged, small devices.