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.  

Castelion is seeking a hands-on Mechanical Assembly, Integration & Test Lead to own the physical assembly, integration, and testing of its long-range hypersonic strike vehicles. This role will lead complete vehicle integration from early prototypes through qualification and production transition, establishing the processes, tooling, and technical rigor required for repeatable flight-hardware builds. The ideal candidate combines deep mechanical judgment with a strong understanding of electrical, avionics, propulsion, and structural interfaces. This is a hands-on technical leadership role that will work directly with engineers and technicians to resolve integration issues, execute ground and flight-test campaigns, and deliver flight-ready vehicles at a high cadence.
Responsibilities 
•  Own assembly, integration, and mechanical test processes for complete long-range hypersonic strike vehicle assemblies, including solid rocket motors, structural and composite components, mechanisms, electrical systems, and avionics.
•  Develop a deep understanding of vehicle-level interfaces, subsystem interactions, operational environments, and field use.
•  Define vehicle integration strategies, build sequences, test flows, acceptance criteria, and readiness assessments.
•  Partner with design, manufacturing, systems, and quality engineering teams to transition hardware from concept and prototype through qualification and production.
•  Evaluate designs for manufacturability, assembly, testability, serviceability, and producibility; drive requirements and design changes through technical reviews.
•  Develop, document, validate, and qualify manufacturing, assembly, and test processes.
•  Create and maintain work instructions, test procedures, manufacturing bills of material, inspection requirements, and quality standards.
•  Design and commission tooling, test stands, lifting equipment, jigs, fixtures, and other integration and test equipment.
•  Lead hands-on build and test operations alongside engineers and technicians, including flight-hardware assembly, subsystem installation, functional testing, environmental testing, acceptance testing, and test-data review.
•  Establish acceptance criteria, assess test results, and make technical recommendations for subsystem and vehicle readiness.
•  Lead fault isolation, root cause analysis, corrective action, and resolution of mechanical and cross-disciplinary integration issues.
•  Coordinate with supply chain, vendors, fabricators, and subcontractors to ensure components and subsystems are delivered in a configuration ready for vehicle integration.
•  Establish scalable processes that support rapid development while enabling repeatable, production-ready vehicle builds.
•  Balance technical rigor, safety, schedule, and program objectives in a fast-paced hardware-development environment.
Basic Qualifications
•  Bachelor’s degree in mechanical engineering, aerospace engineering, or a related technical field.
•  8+ years of professional experience in aerospace, defense, or another high-reliability hardware environment, with significant responsibility for vehicle integration, assembly, testing, or production transition.
•  Demonstrated ownership of complex aerospace hardware from prototype development through qualification or production.
•  Experience leading hands-on assembly, integration, and test activities for complex mechanical or electromechanical systems.
•  Strong understanding of mechanical design, structural interfaces, fasteners, materials, tolerances, and assembly processes.
•  Experience integrating electrical, avionics, wiring, and power or data systems into mechanical assemblies.
•  Proficiency with 3D CAD software; Siemens NX experience preferred.
•  Ability to lead cross-functional technical work and resolve ambiguous, system-level hardware problems.
Preferred Skills and Experience
•  Experience with missiles, launch vehicles, spacecraft, aircraft, propulsion systems, or other complex flight vehicles.
•  Experience developing and executing qualification, environmental, functional, and acceptance test campaigns.
•  Experience with solid rocket motors, energetic systems, or propulsion-system integration.
•  Experience designing tooling, fixtures, ground-support equipment, or mechanical test equipment.
•  Experience with large-scale assembly operations, including lifting and handling, crane operations, facility logistics, and safe hardware flow.
•  Experience with instrumentation, data-acquisition systems, test automation, and data analysis using Python, MATLAB, or similar tools.
•  Proficiency in geometric dimensioning and tolerancing and analysis of complex tolerance stack-ups.
•  Experience developing production processes, manufacturing bills of material, work instructions, inspection plans, and configuration-controlled build records.

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 application, participate in the interview process, or otherwise participate in the hiring process, please contact hr@castelion.com. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law. 

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation. 

EAR/ITAR Requirements 

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.