Mission Design Engineer

About the role

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.

Mission Design Engineer
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:

Mission Design & Operational Analysis

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.

Modeling, Simulation & Data-Driven Design

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.

Prototype Development, Integration & Test

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.

Cross-Functional Collaboration

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 - including 100% employee-covered medical  and strong dependent coverage, along with dental and vision plans. We also provide paid  parental leave to support growing families, a $100 monthly fitness stipend to promote  health and performance, and onsite EV charging for convenience. In addition, employees  enjoy perks like catered meals, company-covered food during high-demand periods, and a  fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance,  it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–  issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are  eligible for a security clearance.

Affirmative Action/EEO Statement

Employment with Castelion is governed on the basis of competence and qualifications and  will not be influenced in any manner by race, color, religion, gender, national  origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity,  marital status, mental or physical disability or any other legally protected status.