NextGen Federal Systems, LLC is seeking a Software Engineer with experience in Systems Tool Kit (STK) to support the development and integration of mission analysis and modeling applications. These applications enable multi-domain analysis—including air, space, ground, and maritime systems—by leveraging physics-based modeling and simulation to assess system performance, coverage, communications, and operational effectiveness. Responsibilities include software development, configuration, and execution; result interpretation; documentation; and modification and maintenance of tools and code. The selected candidate must be quick to learn, adaptable, and agile, interfacing directly with end-customers and customer leadership. The software engineer will provide a full range of systems and software engineering to support critical mission analyses.