LMI is actively seeking a skilled, experienced Senior Software Test Engineer to join LMI's Space Market modeling and simulation (M&S) development team in Colorado Springs, CO. This role involves working directly with USSF and US Government customers, as well as analytical partners, to translate wargame, exercise, training, and analytic needs into responsive, high-performance software applications within LMI's Modeling, Simulation, Prototyping, Wargaming, & Analysis platform, RAPTR. The ideal candidate is adept at applying systems engineering principles in modern software environments, with strong understanding of software integration and testing, and familiarity with Dev. Sec. Ops pipelines, CI/ CD practices, and cloud-native architectures. Candidates should be comfortable working across disciplines to integrate and test modeling and simulation software in secure environments (both on-prem and cloud-based), collaborating closely with developers and engineers to validate end-to-end functionality, and lead agile software systems engineering activities. LMI is a new breed of digital solutions provider dedicated to accelerating government impact with innovation and speed. Investing in technology and prototypes ahead of need, LMI brings commercial-grade platforms and mission-ready AI to federal agencies at commercial speed. Leveraging our mission-ready technology and solutions, proven expertise in federal deployment, and strategic relationships, we enhance outcomes for the government, efficiently and effectively. With a focus on agility and collaboration, LMI serves the defense, space, healthcare, and energy sectors - helping agencies navigate complexity and outpace change. Headquartered in Tysons, Virginia, LMI is committed to delivering impactful results that strengthen missions and drive lasting value. This position requires an active Top Secret clearance and on-site presence in Colorado Springs, CO. Responsibilities Review, develop, document, and maintain system requirements and traceability across program. Collaborate across engineering disciplines, working closely with software developers and system architects to validate end-to-end functionality and M&S effectiveness. Lead integration and test of M&S software applications in secure DoD environments, ensuring interoperability, performance, and usability. Define test strategies, plans, procedures, and acceptance criteria for component, integration, and system-level testing. Design and execute verification & validation activities. Analyze test results, perform root cause analyses, and recommend corrective actions. Apply modern Dev. Sec. Ops practices - including CI/ CD pipelines, automated testing, containerized deployments, and infrastructure as code - to streamline integration and test activities. Contribute to risk, issue, and opportunity management; assess and report technical readiness and critical path impacts. Document software development plans, results and test findings, and readiness assessments for formal customer deliverables Actively collaborate in cross-functional engineering working groups to review, assess, and mature software artifacts such as system architecture, system behavior, system interfaces and requirements, software test plans, UI/ UX designs, functional allocation, Interface Control Documents/ Descriptions (IC - Ds), and data models Qualifications Required:Bachelor's degree in Computer Science/ Engineering, Systems Engineering or equivalent STEM field with 10 years of professional experience (8 years with Master's degree)Strong understanding of software testing principles and methodologies. Practical experience with requirements tracing and configuration management. Experience writing test plans and procedures and executing systems-level integration and verification. Familiarity with software collaboration tools (Jira, Confluence, Git)Familiarity with secure software development practices and CI/ CD pipelines. Strong systems thinking, analytical and problem-solving skills. Excellent communication and teamwork abilities. Active TS Clearance, US Citizenship required. Desired:Advanced degree in Systems Engineering or related field. Familiarity with modeling and simulation concepts Knowledge of cloud (AWS, Azure, or Google Cloud), containerization, and CI/ CD test infrastructure (Docker, Kubernetes)Knowledge of cybersecurity best practices and Do. W certification to field processes. Prior experience working on government-related projects. Space domain exercise, training, or wargaming experience and familiarity with space-focused software solutions. Active TS clearance with SCI eligibility. Target salary range: $100,000 - 170,000. Final compensation will be determined by a variety of factors including but not limited to your skills, experience, education, and/or certifications. #LI-SH 1 Applicants must meet eligibility requirements for a U.S. Government security clearance. Only US Citizens are eligible for a security clearance. For this position, LMI will only consider applicants with security clearances or applicants who are eligible for security clearances, due to the nature of the work.