To address NASA's need for advanced nondestructive evaluation (NDE) of complex built-up spacecraft structures, Physical Optics Corporation (POC) proposes to develop a new Multifunctional Compton Inspection Tool (MCIT) for operation onboard the International Space Station (ISS), based on POC's previously developed Compton imaging tomography (CIT) approach. CIT works by acquiring two-dimensional (2D) images of Compton-scattered X-ray radiation produced by multiple slice views of the object, with subsequent three-dimensional (3D) reconstruction of the inspected structure for high-resolution detection and localization of defects. The MCIT incorporates new features and modifications of the CIT, which permit it to operate in multiple modes with enhanced functionality, smaller form factor, and smaller weight. The proposed MCIT will allow noncontact, single-sided inspection of various spacecraft structures (such as micrometeoroid and orbital debris (MMOD) shields, pressure vessels, ISS modules, and thermal protection of visiting spacecraft) from either within the pressurized habitable compartments or open space. In Phase I POC will demonstrate the feasibility of using MCIT for NDE of spacecraft components by fabricating and testing a TRL-4 prototype, with the goal of achieving TRL-6 by the end of Phase II.