Senior Aerothermal and CFD Engineer

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

We are seeking a Sr. Aerothermal & CFD Engineer to develop aerodynamic, aerothermal, and fluid dynamic solutions for Castelion's long-range hypersonic strike vehicles. This role is critical to predicting and optimizing vehicle performance in extreme flight environments, including high-Mach atmospheric flight and re-entry regimes. You will work hands-on with multidisciplinary engineering teams to analyze, model, and validate aerodynamic and thermal behavior using computational and experimental methods in a fast-paced, hardware-driven environment.

Responsibilities

• Develop aerodynamic and aerothermal models for hypersonic flight vehicles across a wide range of Mach numbers and flight conditions
• Perform computational fluid dynamics (CFD) analyses to predict pressure, heating, flow separation, shock interactions, and control surface effectiveness
• Analyze transient and steady-state thermal environments to support TPS, structures, propulsion, and subsystem integration
• Develop and validate aerodynamic databases for simulation, guidance, control, and flight performance analysis
• Work closely with TPS, structures, propulsion, GNC, and flight sciences teams to ensure seamless integration of aerodynamic and thermal design solutions
• Support vehicle configuration trades and optimization studies to improve performance, controllability, and thermal survivability
• Correlate CFD predictions with wind tunnel, arc-jet, ground test, and flight test data to improve model fidelity
• Develop tools and workflows for aerodynamic, thermal, and fluid dynamic analysis and automation
• Support flight test planning and post-flight data analysis, translating results into system-level improvements
• Mentor junior engineers and contribute to best practices in CFD and aerothermal analysis
• Partner closely with program leadership to make technical trades aligned with mission success

Basic Qualifications

• Bachelor's, Master's, or PhD in Aerospace Engineering, Mechanical Engineering, or related field
• 5+ years of experience in aerodynamic, aerothermal, or CFD analysis for aerospace or high-speed flight systems
• Strong background in compressible fluid dynamics, hypersonic aerodynamics, and heat transfer
• Experience performing CFD analysis using tools such as STAR-CCM+, Fluent, FUN3D, CFD++, or equivalent
• Familiarity with turbulence modeling, boundary layer analysis, and high-temperature gas effects in hypersonic flow regimes
• Experience generating aerodynamic and aerothermal databases for simulation and flight analysis
• Familiarity with wind tunnel testing, flight test correlation, or experimental aerothermal methods
• Experience with scripting and automation tools such as Python or MATLAB for data processing and workflow development
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high-flight cadence environment

Additional Requirements

• Willingness to support extended hours or weekend work during critical integration, test, and flight milestones.

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.