To address the NASA GSFC need for significant improvements in wide bandgap materials and detectors for UV applications, Physical Optics Corporation (POC) proposes to develop a new AlGaN nanowire photocathode for Silicon Microchannel Plate solar-blind photodetector fabricated directly on the MCP entrance plane. This innovative photocathode and the technology of its growth on the Si microchannel plate enables us to meet NASA requirements for windowless operation in the FUV range with high quantum efficiency, low noise, radiation-hardness, reliability, and potentially low cost. In Phase I, POC demonstrated the technology of GaN and AlN nanowire growth by Hydride Vapor Phase Epitaxy and investigated the properties of nanowire surfaces. In Phase II, POC will optimize this technology for fabrication of an AlGaN nanowire photocathode on a silicon MCP structure and demonstrate photodetector operation in the FUV range. This innovative, efficient, solar-blind, and radiation-hard UV photodetector with low background noise and a large sensing area will offer NASA capabilities to design new instrumentation with improved sensitivity and spatial or spectral resolution for FUV and UV instruments for several missions devoted to a better understanding of the origin of the Universe and its evolution to modern form.