Principal Mechanical Engineer

Principal Mechanical EngineerMission Technologies, a division of HII, is expanding - and we're looking for bold, inventive Principal Mechanical Engineers to join our fast-moving, interdisciplinary teams in our Alexandria, VA. At Mission Technologies, we design and build customized, mission-enabling solutions for the defense and intelligence communities—solutions that fuse cutting-edge technology with real-world tradecraft. Our teams are filled with imaginative builders, hands-on problem solvers, and curious minds from a wide range of backgrounds. Here, collaboration isn't just a value—it's the way the work gets done. You'll be part of small, high-trust teams that turn ideas into functional hardware at remarkable speed. If you love tackling open-ended problems, experimenting with new technologies, and seeing your designs come to life in the field, this is the place for you. Bring your mechanical engineering expertise—and shape the role based on your strengths, interests, and creativity. You'll work on rapid-turn projects that go from concept to deployment, contributing to hardware used by end-users around the world. Your impact will include:Hands-On Design & Prototyping: Apply your mechanical engineer fundamentals to a diverse, mission-critical projects. This includes developing solutions like electromechanical devices, motion platforms, electronics packaging, and multi-spectral signature management (visible, NIR, thermal, acoustic, RF).DFM Focus: Leverage your understanding of Design for Manufacturing (DFM) to ensure your designs are optimized for both subtractive and additive manufacturing methods.Cross-Functional Collaboration: Work shoulder-to-shoulder with senior engineers, technicians, managers, and end-user clients in small, close-knit teams. Clear communication and adaptability are key as you iterate quickly within small, agile teams.System Integration: Use your awareness of electrical systems to ensure all mechanical designs integrate seamlessly into complete products.Joining HII means joining a team with decades of proven impact: Impactful Work: Earn a sense of accomplishment by making meaningful contributions to our nation's top security priorities. Rapid Prototyping: Access to some of the most comprehensive secure rapid prototyping facilities in the mid-Atlantic region, including a full in-house machine shop, composite fabrication, finishing, electronics assembly, and testing capabilities.Essential Job Responsibilities:Provide support to the design, development, prototype fabrication, and verification testing of unique specialty productsPerform detailed system and sub-system analysis, simulation, and design work as requiredWork with complicated mechanical system concepts and detailed designs to properly determine the necessary design tradeoffsInterface with project teams and external customers as required, to support specialized product developmentParticipate in the assembly, system test planning, and system test procedure generationAdequately document processes, procedures, and testing using structured formats. Where formats do not currently exist, provide a recommended format for reviewLearn and utilize the Quality Management System (QMS) and existing tools and templatesMinimum Qualifications:Level Requirements: Level 5: 15 years relevant experience with Bachelors in related field; 13 years relevant experience with Masters in related field; or 10 years relevant experience with PhD or Juris Doctorate in related field.Clearance Requirement: Active US Secret clearance required, with ability to obtain TS/SCI.Technical Requirements: Experience with mechanical CAD tools. Proven mechanical design experience (mechanisms, power trains, thermal management, structures, embedded electronics). Experience with various manufacturing methods (additive, machining, sheet metal, PCBAs, cable harnesses, composites). Hands-on assembly experience. Strong documentation skills (2D engineering drawings, PowerPoint, Visio, Adobe suite). Creativity and comfort with open-ended, precedent-free problem solving.Preferred Requirements:Advanced fabrication experience (welding, composite layups, machining, industrial finishes and paints).Simple embedded electronics work (Jetson, Arduino, RPi) and associated Python or C++ programming skills.Experience using computational fluid dynamics (CFD and/or FEA for stress, deformation, and modal analysis).Working knowledge of RF systems (signal analyzers, SDRs, antennas, amplifiers).Experience with project management (Earned value mgmt, estimating, requirements capture).Physical Requirements: May require working in an office, industrial, shipboard, or laboratory environment. Capable of climbing ladders and tolerating confined spaces and extreme temperature variances.