Mechanical Engineer

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 and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts. This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact. Role Overview: As a Mechanical Engineer (Test & Tooling), you will own the design, development, and deployment of mechanical systems that enable rapid, high-fidelity testing and scalable production of avionics and integrated weapon subsystems. You will lead the creation of environmental test fixtures (vibration, thermal, HALT/HASS), hardware-in-the-loop (HITL) and vehicle-in-the-loop (VITL) support hardware, production test equipment, and production tooling that accelerates build and integration. You will partner closely with cross-functional design, test, and manufacturing engineering teams to ensure hardware can be validated quickly, reliably, and at large scale for production. This role requires stro...