SMARTPS-A Rapid Inspection Method for Thermal Protection Systems
SRI is assisting the NASA AmesResearch Center in the development of technology for more rapid
inspection of the thermal protection system (TPS) of future reusable space vehicles.
Currently, an inspector looks into the gaps between each of the more than 20,000 tiles
on a space shuttle. If hot gases penetrate too close to the vehicle's hull during reentry,
the adhesive holding the tiles in place overheats and changes from its natural red color to
black. The inspector is looking for that color change.
SRI is developing wireless, embedded over-limit temperature sensors for more efficient inspection.
These small, lightweight sensors will passively respond to environmental changes (overheating)
while the vehicle reenters the atmosphere, and will be integrated with commercial radio frequency
identification (RFID) tag technology. One sensor will be placed in the adhesive in each gap.
On the ground, RF illumination powers each microtag.
When queried, each microtag responds with its unique identifying code and temperature status,
providing registered tile-health data to the inspectors.
Passive wireless embedded microtags have numerous applications beyond space vehicles, including
condition-based maintenance of aircraft and bridge decks, and quality control of inventory,
shipments, and industrial processes.
Currently, an inspector looks into the gaps between each of the more than 20,000 tiles
on a space shuttle. If hot gases penetrate too close to the vehicle's hull during reentry,
the adhesive holding the tiles in place overheats and changes from its natural red color to
black. The inspector is looking for that color change.
atmosphere, and will be integrated with commercial radio frequency
identification (RFID) tag technology. One sensor will be placed in the adhesive in each gap.
On the ground, RF illumination powers each microtag.
When queried, each microtag responds with its unique identifying code and temperature status,
providing registered tile-health data to the inspectors. 
R&D Divisions