Development Test Engineer

About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production at scale. We're designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Development Test Engineer

The Development Test Engineer owns the planning, execution, and analysis of tests that turn designs into flight-ready hardware. This role sits at the center of engineering, manufacturing, and operations—translating requirements into real-world validation through benchtop, environmental, subsystem, and vehicle-level testing. You will design test hardware, write procedures, run tests, break things early, and close the loop back into design with clear data and recommendations.

This is a hands-on role for engineers who thrive in fast-paced, ambiguity-heavy environments and believe the fastest way to learn is to test real hardware.

Responsibilities

• Own development and qualification testing for avionics, mechanisms, propulsion, structures, and integrated vehicle subsystems

• Design and build test fixtures, ground support equipment (GSE), and instrumentation for benchtop, environmental, and system-level tests

• Author test plans, procedures, and reports aligned with program requirements and qualification intent

• Execute vibration, thermal, shock, EMI/EMC, functional, and performance testing

• Instrument hardware and vehicles with sensors (strain, temp, pressure, accel, current/voltage) and DAQ systems

• Lead anomaly detection, root-cause analysis, and corrective action closure

• Partner closely with design engineering to feed test results back into rapid design iteration

• Support integration operations, range testing, and flight test campaigns as needed

• Maintain rigorous configuration control, data management, and test documentation

• Improve test infrastructure, automation, and data quality to increase test cadence and learning velocity Basic Qualifications

• Bachelors degree in Mechanical, Electrical, Aerospace, or related engineering field

• 3+ years of hands-on development and test experience (academic, industry, or both)

• Experience planning and executing hardware tests from concept through report-out

• Proficiency with test instrumentation and lab equipment (DAQs, oscilloscopes, power supplies, sensors)

• Ability to design and fabricate simple test fixtures and GSE (CAD + shop familiarity)

• Strong debugging, troubleshooting, and root-cause analysis skills

• Comfortable working across disciplines in high-ownership environments

• Willingness to support extended hours, weekends, travel, and on-site operations during critical test campaigns

• Operates with high ownership, bias to action, attention to detail, and a test-driven engineering mindset

• Comfortable working in fast-moving environments where hardware is the source of truth Preferred Skills and Experience

• Aerospace, missile, launch vehicle, space, or defense hardware testing

• Environmental testing: vibration, thermal-vacuum, thermal cycling, shock

• Test automation and data analysis using Python, MATLAB, or similar

• Flight test, range operations, or hardware-in-the-loop (HIL) experience

• Familiarity with requirements verification, qualification evidence, and failure tracking

• Hands-on machining, wiring, soldering, or rapid prototyping experience All employees are granted long-term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.

Leadership Qualities

Bias to Action and Creative Problem Solving . Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.

High Commitment, High Initiative . A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.

Clear Communicator . Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

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. 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.