On February 1, 2003, the Space Shuttle Columbia broke up on reentry. The Columbia Accident Investigation Board (CAIB) concluded that the accident was caused by a piece of insulating foam that fell from the external tank. To foretell or prevent such event in the future we plan to add intelligence to the Shuttle thermal protection system, using “smart tiles” that have integrated damage sensors. The tiles will let us know early enough when the surface of the Shuttle has been damaged, so that repairs can be done.
Optical fibers cannot be integrated into the tiles of the Thermal Protection System (TPS) of the Space Shuttle without some margin of error, and manufacturability of fibers is challenging. The fibers are brittle, hard to place in location, and hard to connect or couple to any source, which makes them hard to handle and difficult to integrate into the tiles. Maltreatment of the fibers can cause them to break or develop surface flaws. We have successfully integrated fibers into tiles, and also coupled them to light emitting diodes (LEDs) and PIN photodiodes to transmit and receive a signal through the fibers. The signal will serve as a sensor and damage to the fiber will indicate changes in transmission. Jon’s most recent work involves transmitting an electrical signal from one fiber end to another while having an air gap between the fibers and amplifying the signal.