Zachary Piper Solutions is seeking a Model-Based Systems Engineer (MBSE) Level 3 to support advanced aerospace and defense programs within a leading national security organization. You’ll join a high‑impact Systems Engineering & Integration team driving next‑generation autonomous and weapons system development across highly complex, proprietary programs. This role is ideal for engineers who thrive in fast-paced environments and want to contribute directly to mission-critical, cutting-edge systems. This role is fully onsite in St. Louis, Missouri or Seattle, Washington. Candidates must hold an active secret clearance. Responsibilities Include: • Support cross-functional engineering teams in developing advanced autonomous and complex systems aligned with program milestones and customer expectations. • Implement and mature Model-Based Systems Engineering (MBSE) methodologies within a Digital Engineering ecosystem. • Develop and maintain system architectures, requirements, and interfaces using tools such as Cameo, MSOSA, and SysML. • Execute full lifecycle systems engineering activities, including: • Requirements decomposition & traceability • System architecture modeling • Interface definition & management • Operational and environments analysis • Specification development • Trade studies and technical assessments • Risk identification & mitigation • Verification, validation, and test planning • Certification planning & execution • Support technical reviews, documentation, and customer-facing deliverables. • Collaborate with SMEs across multiple engineering disciplines to integrate complex system capabilities. Required Qualifications: • Bachelor’s degree in Engineering, Engineering Technology, Computer Science, Physics, Mathematics, Chemistry, or related technical field. • 5+ years of engineering experience with a Bachelor’s, 3+ years with a Master’s, or relevant experience with a PhD. • Hands-on experience with MBSE, Cameo/MSOSA, and/or SysML. • Active Secret Clearance (required prior to start). • Ability to work 100% onsite in St. Louis or Seattle. Preferred Skills: • Experience supporting proprietary or classified aerospace/defense programs. • Background in autonomy, mission systems, or advanced weapons system development. • Familiarity with Digital Engineering pipelines and model-based lifecycle integration. • Strong communication skills and comfort working with multidisciplinary engineering teams. Compensation and Benefits: • Salary Range: $90,000-$160,000 **depending on experience** • Full Benefits: Cigna Medical, Dental, Vision, 401K, PTO, Sick Leave if required by law, and Holidays