Mechanical Engineer at Castelion in Allen, TX

Job description

Why Castelion, Why Now Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability. This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function. Mechanical Engineer Design, build, and test the mechanical components and assemblies that enable Castelion’s next-generation RF sensors. In this role, you will work at the intersection of mechanical, thermal, and electrical engineering to develop electro-mechanical solutions from initial concept through production. You will own the mechanical design of RF sensor circuit card assemblies (CCAs), develop test fixtures that enable rapid integration and validation, and work hands-on with cross-functional engineering teams to turn designs into reliable, production-ready hardware. Responsibilities Own the mechanical design and development of RF sensor circuit card assemblies (CCAs), ensuring designs meet system-level requirements for fit, function, structural integrity, and thermal performance. Design, develop, and release mechanical fixtures and tooling required for CCA integration, characterization, verification, and testing. Create and maintain detailed engineering documentation, including CAD models, drawings, tolerances, material specifications, part numbers, and revision-controlled design records. Collaborate closely with electrical, thermal, and systems engineers to develop integrated hardware solutions and resolve mechanical design and interface challenges. Lead mechanical integration, testing, and design verification activities, using test results and integration feedback to drive rapid design iterations and improvements Identify and resolve mechanical integration issues through hands-on troubleshooting, prototyping, experimentation, and root-cause analysis. Optimize designs for manufacturability, reliability, and repeatability, accounting for fabrication methods, assembly processes, and production constraints. Drive mechanical designs from initial concept through prototyping, integration, testing, and production release, taking ownership of technical execution and deliverables. Continuously improve hardware designs based on test data, manufacturing feedback, and evolving system requirements. Basic Qualifications Bachelor’s degree in Mechanical Engineering or a related engineering discipline. 2+ years of professional mechanical engineering experience, preferably in aerospace, automotive, defense, or other hardware-focused industries. Proficiency in 3D CAD design and mechanical drawing development using Siemens NX, SolidWorks, or similar tools. Foundational understanding of statics, dynamics, thermal principles, materials, tolerances, and mechanical interfaces. Experience developing mechanical components, assemblies, prototypes, or fixtures. Strong attention to detail in engineering drawings, materials selection, part numbers, tolerances, and technical documentation. Ownership mentality and a willingness to take responsibility, work hands-on with hardware, and learn through rapid iteration. Ability to collaborate effectively across mechanical, electrical, thermal, and test engineering disciplines. Preferred Skills and Experience Experience integrating, testing, and validating electro-mechanical subsystems within complex hardware systems. Familiarity with PCB design concepts, electrical schematics, circuit card layouts, and mechanical enclosure integration. Experience designing mechanical interfaces, enclosures, mounting solutions, and test fixtures for electronic assemblies. Familiarity with RF sensors, radar, avionics, or communications systems in aerospace or defense environments.