The proposed project seeks to increase the reliability of cold spray additive manufacturing (AM). Cold spray technology has been developed into a large format (1 m x 1 m in x-y) commercial AM system (called WarpSPEE3D) by the Australian company SPEE3D. The Australian Army is currently testing the enclosed, modular AM system in the Australian bush as a field-ready AM system. Supply chain and logistics issues can cause long delays in obtaining spare parts needed for Army vehicle and machine repairs, and the result is reduced readiness and increased vulnerability of units at or near the battlefield. Cold spray AM is the fastest commercial metal AM technique currently available, and its use at forward operating bases could help close the supply gap and deliver spare parts for vehicles within hours rather than days or weeks. Elementum 3D, Inc. has purchased a commercial WarpSPEE3D system. In partnership with the Georgia Institute of Technology and Addiguru, the company proposes in this project to evaluate the feasibility of an in situ combined mass and optical measurement system to monitor and control the deposition rate of material for lightning fast, defect-free spare part fabrication.