Thermal Protection Systems Nondestructive Evaluation Tool

To address NASA's need for evaluation of bondline and in-depth integrity for lightweight rigid and/or flexible ablative materials, Physical Optics Corporation (POC) proposes to develop a novel Thermal Protection System Nondestructive Evaluation Tool (TERRET) providing accurate in situ detection, identification, and spatial localization of internal and surface defects (cracks, voids, delaminations, porosity, and inclusions), and evaluation of bondlines and in-depth integrity of lightweight, rigid, and/or flexible ablative materials and large-area multilayer thermal protection system (TPS) structures with complex geometries. TERRET is based on the POC-patented innovative X-ray Compton imaging tomography technique and POC-patented apodized aperture X-ray imaging optics with high spatial resolution and a wide field of view, substantially modified and optimized to meet NASA's requirements for operation on a wide range of lightweight TPS materials, noncontact operation, portability, and ease of use. TERRET will provide detection and spatial localization of defects and damage in TPS material and structures, with spatial resolution of ~1 mm and sensitivity of 1% in material density difference. In Phase I POC will demonstrate the feasibility of TERRET for NDE of TPS by fabricating and testing a TRL-4 prototype, with the goal of achieving TRL-6 by the end of Phase II.