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 Silicon Microchannel Plate solar-blind photodetector with an AlGaN nanowire photocathode fabricated directly on the MCP entrance plane (NW-Si-MCP). This innovative photocathode and the technology of its growth on the Si microchannel plate enables us to meet NASA requirements for high quantum efficiency, low noise, radiation-hard, reliable, and potentially low cost solar-blind photodetectors. The large size and high number of microchannels offers superior spectral and spatial resolution for future NASA space instruments involved in the investigation of the origin of Universe, planet finding, and understanding Sun-Earth interactions while simultaneously improving the sensitivity of new instruments and avoiding an expensive increase of their cost due to optical system size. In Phase I, POC will demonstrate the feasibility of fabrication of AlGaN nanowire photocathodes for NW-Si-MCP detectors by fabricating the photocathode samples and demonstrating their quantum efficiency in the spectral range from 100 nm to 200 nm (TRL level 4). In Phase II, POC plans to develop a fully functional NW-Si-MCP prototype and demonstrate its long-term operation in harsh conditions (TRL level 6).