Weapons Integration Engineer (Multiple Levels)

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. Weapons Integration Engineer (Multiple Levels) As a Weapons Integration Engineer you will be part of the team that ensures Castelion weapon systems integrate seamlessly with ground launchers, tactical/multi-role aircraft, and future systems. You will own platform integration efforts from early concept and capability studies through prototype development, test, and operational deployment - collaborating with propulsion, avionics, GNC, software, flight test, and manufacturing teams to deliver mission-ready solutions. • Weapons Integration Engineer • Sr. Weapons Integration Engineer • Weapons Integration Engineer, Mission Systems • Weapons Integration Engineer, Airworthiness & Certification • Weapons Integration Engineer, Launcher & Platforms • Weapons Integration Engineer, Special Programs (TS/SCI required) Core Responsibilities • Serve as the primary technical liaison between Castelion and government customers, platform manufacturers, and other external stakeholders to ensure alignment between mission requirements and system designs. • Support development of advanced weapon concepts and technologies, with emphasis on missile integration for ground launchers and tactical aircraft. • Develop, maintain, and execute fast-paced integration plans and schedules to deliver and field weapon systems. • Lead mission planning, verification, and test efforts (including live-fire and flight tests): pre-test analysis, real-time mission support, and post-test evaluation and reporting. • Review and assess interface specifications, drawings, and design documents for functional, electrical, software, and physical interfaces; identify and close interface gaps. • Collaborate across internal engineering teams (propulsion, avionics, GNC, software, flight test, manufacturing) to perform design trades and optimize overall system performance with a focus on platform compatibility. • Develop and coordinate technical specifications, integration documentation, and certification/supporting artifacts required for customer acceptance and regulatory compliance. • Represent Castelion at customer meetings, design reviews, test campaigns, and demonstrations. • Ensure contract deliverables meet customer requirements, schedule, and quality standards. Focus Areas & Specialization Tracks Weapons Integration Engineers at Castelion operate across the full system lifecycle, from early concept through deployment. While all engineers are expected to maintain strong system-level ownership, individuals may develop deeper expertise in one or more of the following areas: • Mission Systems Integration Define and integrate mission-level capabilities by translating operational requirements into system performance. Includes mission planning, CONOPS development, fire control integration, and software development to deliver mission-ready weapon systems. • Airworthiness & Certification Ensure systems meet safety, regulatory, and platform certification requirements. Includes development of airworthiness strategies, compliance with military standards, and coordination with government certification authorities. Lead qualification efforts and guide systems through safety review boards (WSESRB, JS-WSR, FISTRP, AISSRB, SSSTRP), as well as Seek Eagle, NAVAIR Airworthiness, and related certification processes. • Launchers & Platform Integration Lead integration of weapon systems with tactical aircraft, ground launchers, and emerging platforms. Define and validate mechanical, electrical, and software interfaces while coordinating with platform manufacturers and external partners. Includes hands-on prototype development, integration hardware, test equipment, and travel to customer sites. • Test & Evaluation (T&E) Plan and execute ground and flight test campaigns, including live-fire events. Responsibilities include pre-test analysis, real-time mission support, post-test data analysis, and rapid iteration based on results. Conduct fit checks, system validation, and integration verification activities. • Logistics, Fielding & Operational Support Support transition from development to operational deployment. Includes fielding strategies, sustainment planning, user coordination, and ensuring mission readiness in real-world environments. Basic Qualifications • Bachelors degree in aerospace, mechanical, electrical engineering, physics, or related technical field. • 2+ years experience in systems engineering, mission/weapon integration, or related roles within defense or aerospace. • 2+ years experience in technical project management or weapons system development. • Hands-on experience with launch vehicles, weapons systems, system integration, or aerospace defense platforms • Experience working with the DoD or other national security agencies. • Strong analytical skills: ability to synthesize complex technical information and communicate effectively to engineers and non-technical stakeholders • Ability to obtain and maintain Top Secret/SCI clearance • Ability to travel up to 25% for customer meetings, test campaigns, and program execution Preferred Skills and Experience • Masters degree in a relevant technical field. • Hands-on experience with hypersonic weapons, missile defense, or platform integration • Strong background in mission design, development, integration, and test for missiles, spacecraft, or similar systems • Demonstrated success integrating weapons or sensors with tactical aircraft and/or ground-based launch systems • Active Top Secret/SCI clearance preferred Additional Requirements • Ability to put in extended hours, including evenings and weekends, when required to meet aggressive timelines • This role is based in Torrance, CA and requires full-time onsite presence Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details. Other Duties Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice. Additional Eligibility Requirements This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply. Affirmative Action/EEO Statement Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law. Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an appl