Senior Software Engineer

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. Responsibilities Develop, customize, and maintain STK-based applications to support mission planning, analysis, and visualization Integrate STK (Engine, Components, or Desktop) with external tools, models, and data sources to enable end-to-end mission workflows Implement backend services using Python and support frontend interfaces as needed Analyze and interpret simulation results, providing actionable insights to engineering teams and stakeholders Support traceability between mission analysis outputs and system models, ensuring consistency across the digital engineering environment Support deployment and execution of applications in modern environments (e.g., containerized or cloud-based) Contribute to documentation, user guides, and technical deliverables Troubleshoot and enhance existing tools to improve performance, usability, and scalability Qualifications BS or equivalent in Computer Science, Engineering, Mathematics, or equivalent technical degree 5+ years’ prior work experience in the aerospace or defense industry, with demonstrated software development experience Experience customizing or automating STK-based tools or applications highly desired (including STK, STK Engine, STK Components, and/or Cesium) Experience integrating tools via APIs (REST or similar) Proficiency in Python and experience with backend frameworks such as Flask is required Strong expertise in React JS for building modern and responsive user interfaces is highly desirable Knowledge of version control systems, preferably Git is highly desirable Proven experience as a Full Stack Developer or similar role is highly desirable Capable of self-management and responsibly executing multiple tasks in accordance with priorities and deadlines Active Top Secret (TS) clearance required (SCI eligibility preferred) Preferred Qualifications Experience with STK Engine, STK Components, or Cesium Experience linking STK analyses to MBSE environments (e.g., parameter passing, trade studies, digital thread integration) Familiarity with digital engineering ecosystems, mission thread development, or model orchestration tools Experience with Docker, cloud environments, or DevSecOps practices Frontend development experience (e.g., React) Equal Opportunity Employer/Protected Veterans/Individuals with Disabilities. #J-18808-Ljbffr