Senior Test 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.

Senior Test Engineer, Solid Rocket Motors & Hypersonic Systems

We are seeking a Senior Test Engineer to lead testing activities for solid rocket motors (SRM) and integrated hypersonic strike vehicles at Castelion. This role is responsible for developing and executing test plans for static fire testing, environmental qualification, functional verification, and flight test support. You will work hands-on with propulsion hardware, instrumentation, data acquisition systems, and test infrastructure while ensuring the highest standards of safety, data quality, and mission success. Partnering closely with Propulsion, Manufacturing, Integration & Test, and Design teams, you will drive test readiness for prototype, qualification, and production hardware on aggressive development timelines for programs like Blackbeard.

Responsibilities

• Lead the development of comprehensive test plans, procedures, and requirements for SRM static fires, environmental testing (vibration, thermal, shock, humidity), functional checkout, and vehicle-level integration testing.
• Design, commission, and operate test fixtures, instrumentation setups, and data acquisition systems for thrust, pressure, temperature, vibration, and other critical parameters.
• Execute and oversee static fire tests, environmental stress screening, and other qualification tests, ensuring safe operations with energetic materials and high-consequence hardware.
• Perform real-time test monitoring, data reduction, analysis, and reporting; identify anomalies and lead root-cause investigations with cross-functional teams.
• Support flight test campaigns, including pre-flight checkout, range coordination, telemetry monitoring, and post-flight data analysis.
• Drive continuous improvement in test processes, safety protocols, and efficiency while integrating automation and digital tools for data capture and analysis.
• Collaborate with Manufacturing and Propulsion on testability, design-for-test feedback, and hardware maturation from prototype to rate production.
• Author and maintain test documentation, safety plans, and compliance records in accordance with DoD, range safety, and energetic materials standards.
• Mentor junior test engineers and contribute to building robust test capabilities at Castelion facilities and partner ranges.
• Manage test schedules, resources, and interfaces with internal teams, suppliers, and external test ranges.

Basic Qualifications

• Bachelor's Aerospace Engineering, Systems Engineering, or related field
• 5 years of engineering test experience for solid rocket motors

Preferred Skills and Experience

• Master's degree in Mechanical Engineering, Aerospace Engineering, Systems Engineering, or related field.

• 6–10+ years of test engineering experience in aerospace or defense, with at least 3+ years focused on propulsion, solid rocket motors, or missile systems testing.
• Proven track record developing and executing complex test programs from component through system level, including energetic or hazardous testing.

• Strong hands-on experience with test instrumentation, data acquisition (e.g., LabVIEW, MATLAB, or similar), sensors (pressure transducers, accelerometers, thermocouples), and high-speed data systems.
• Proficiency in test stand design, fixture development, and environmental test equipment (shakers, thermal chambers, etc.).
• Experience with static fire testing, thrust measurement, and ballistic performance evaluation for solid rocket motors.
• Working knowledge of safety protocols for energetic materials, ordnance handling, and high-pressure systems.
• Familiarity with telemetry, flight test operations, and post-test data analysis tools.

• Direct experience with solid rocket motor static fire testing or hypersonic propulsion testing on DoD or NASA programs.
• Background in fast-paced environments (aerospace startups, SpaceX, Anduril, etc.).
• Experience supporting production acceptance testing and scaling test operations for rate production.
• Prior work at test ranges or with range safety processes.
• Familiarity with ITAR-controlled programs and classified testing environments.

• Strong technical problem-solving and analytical skills with a data-driven approach.
• Excellent collaboration and communication abilities across engineering, manufacturing, and test teams.
• Proven ability to lead test execution in high-stakes, safety-critical environments.
• Mentoring mindset and willingness to develop junior engineers.
• Organized, proactive, and comfortable managing multiple concurrent test activities under tight schedules.

Benefits And Perks

• Employee Equity: Meaningful equity for all full-time employees - share value has increased 150x in three years
• Personal Time Off: Four (4) weeks of paid time off to unplug, reset, and come back sharp—velocity matters, burnout doesn't
• Company Paid Holidays: Ten (10) company paid holidays
• Medical: We offer plans at 100% employee covered and 80% of dependent coverage
• Dental & Vision: We cover 90% employees and 80% for dependents to ensure you and your family have access to quality preventive and ongoing care
• FSA/HSA: To support long-term health and financial resilience, we offer FSA and HSA options that allow employees to set aside pre-tax dollars for eligible medical and dependent care expenses
• Retirement: 401k plan offered to support long term financial growth along side high-impact, high-velocity work
• Paid Parental Leave: We support growing families with meaningful time to bond and recover. Birthing parents are eligible for up to 10 weeks of paid leave, while non-birthing parents may take up to 4 weeks of paid leave. This time can be used for pre-natal care, pregnancy, childbirth, and related medical needs—ensuring every parent has the support they need during this important life moment.8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees
• Meals & Catering: Frequently catered lunches and team meals, plus company-covered meals when extra time or effort is required
• Snacks & Beverages: Fully stocked kitchen with unlimited snacks and drinks to keep you fueled throughout the day
• Performance & Fitness: $100 monthly fitness stipend to support peak performance and health, both inside and outside of work
• EV Charging: Onsite electric vehicle charging available for employees

Physical Demands

• Must be willing to work extended hours and/or weekends as needed

• Must be able to travel up to 30%
• Must be able to lift more than 50lbs

ITAR Requirements

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.

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. Failure to obtain or maintain any required clearance or authorization may result in reassignment, leave, or separation from employment, consistent with business needs and applicable law.

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.

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.