Mission Design Engineer

Mission Design Engineer

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.

As a Mission Design Engineer, you will lead mission-level analysis and system design using advanced modeling and simulation tools such as AFSIM and EADSIM. You will evaluate system effectiveness in operational scenarios, translate mission needs into engineering requirements, and inform design decisions through simulation, test, and rapid iteration.

In addition to modeling and analysis, you will play an active role in prototype hardware design, integration, and test, working closely with cross-functional teams to ensure mission-driven insights are realized in real-world systems. This role connects operational analysis directly to hardware, ensuring that simulation results drive tangible performance improvements in deployed systems.

Responsibilities:

• Develop and execute mission-level simulations using AFSIM and EADSIM to evaluate system performance in contested, multi-domain environments.
• Translate operational scenarios and customer needs into system requirements, constraints, and performance metrics.
• Conduct trade studies, sensitivity analyses, and campaign-level assessments to inform system architecture and design decisions.
• Analyze interactions between sensors, weapons, communications, and threat systems to assess mission effectiveness.

• Build, maintain, and extend simulation frameworks representing real-world operational conditions.
• Use simulation outputs to guide design trades across propulsion, GNC, avionics, and software.
• Correlate simulation results with ground and flight test data to improve model accuracy and predictive capability.
• Develop tools and workflows to rapidly evaluate new concepts and configurations.

• Collaborate with hardware and software teams to integrate mission requirements into prototype systems.
• Support system-level integration and ensure alignment between modeled performance and actual system behavior.
• Participate in flight tests and live-fire events, including pre-test analysis, real-time support, and post-test evaluation.
• Use test results to refine both system design and simulation models.

• Work across engineering disciplines (GNC, propulsion, avionics, software, manufacturing).
• Communicate mission-level insights to inform design tradeoffs and prioritization.
• Support design reviews, technical briefings, and customer engagements.

Basic Qualifications:

• Bachelor's degree in aerospace engineering, mechanical engineering, electrical engineering, physics, or related field.
• 2+ years of experience in mission analysis, operational analysis, systems engineering, or aerospace/defense modeling & simulation.
• Experience with AFSIM, EADSIM, or similar tools (e.g., STK, MATLAB/Simulink, custom simulation frameworks).
• Experience translating mission needs into engineering requirements and design trades.
• Familiarity with aerospace or defense systems (missiles, aircraft, spacecraft, or launch vehicles).
• Strong analytical and communication skills.
• Ability to obtain and maintain a Top Secret/SCI clearance.

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.

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.

Benefits And Perks:

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits -…