Description: To incorporate the (1x24) optical switches into the FOSS unit architecture, research will be conducted into establishing communication and synchronization between the optical switches, peripheral sensors and accompanying data acquisition system, sweeping laser and the data management system. # The optical switches will cycle through sensing fibers periodically until an event is triggered. The use of peripheral sensors will provide feedback to the optical switches to intelligently interrogate sensing fibers of interest temporarily, then resume periodic switching. The use of optical switches will also allow for a redundant interrogation path by allowing interrogation from two ends of a sensing fiber. In the event where a sensing fiber is damaged, the fiber could be examined from two ends to recover data that may otherwise have been lost. Redundancy may be critical for certain research vehicles, and is currently unobtainable with the current system architecture.

Benefits: This research also demonstrated the ability to greatly increase sensor counts, and in turn, sensing area of the Armstrong FOSS units. Increase sensing area is highly desirable since damage from MMOD impacts can occur anywhere over a surface, and the resulting damage to the TPS can cause voids in the surface of any size. With all the variability of impact locations and size, a full surface monitoring system could help detect these changes to the TPS. These increase in sensor counts can be achieved with minimal weight and size penalties. The main trade off is the reduction in data acquisition speed. While the switch is changing position, the FOSS unit cannot make measurements. Also, depending on the number of switch positions being implemented, it