Junior Manufacturing Engineer Jobs in California

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 Manufacturing Engineer, Solid Rocket Motors

We are seeking a Senior Manufacturing Engineer to lead key manufacturing processes for solid rocket motors (SRM) supporting Castelion's hypersonic strike weapons, including the Blackbeard program. This role focuses on developing, optimizing, qualifying, and executing production processes for propellant mixing and casting, motor cases, liners/insulators, nozzles, and final motor integration.

You will drive process improvements, support the transition from prototype and research builds to scalable high-rate production, and ensure high quality, safety, and efficiency. Working closely with Design, Propulsion, Automation & Controls, Quality, and Test teams, you will contribute to new product introduction, continuous improvement, and facility ramp-up at our manufacturing sites.

Responsibilities

• Lead development and optimization of assigned SRM manufacturing processes, including propellant formulation/mixing, vacuum casting, filament winding, liner/insulator application, nozzle assembly, curing, and integration.
• Drive Design for Manufacturability (DFM), Design for Assembly (DFA), PFMEA, control plans, and statistical process control (SPC) to improve yield, reduce cycle time, and lower cost.
• Support new product introduction (NPI) and design change implementation by providing manufacturing input and executing process qualifications.
• Perform root-cause analysis and lead corrective/preventive actions for process issues and defects.
• Integrate NDE methods (ultrasonic, CT, shearography, thermography) and in-process inspection into production workflows.
• Collaborate with Automation & Controls to implement robotics, vision systems, and digital tools (MES, data analytics) for improved efficiency and traceability.
• Author and maintain work instructions, process documentation, and training materials; mentor junior manufacturing engineers.
• Ensure compliance with energetic materials handling, DoD 4145.26-M, ATF regulations, ITAR, and explosive safety standards.
• Support equipment qualification, process validation, and production ramp at the Midland, TX facility and the Project Ranger campus in New Mexico.
• Interface with suppliers on materials, tooling, and equipment to resolve issues and improve incoming quality.

Basic Qualifications

• Bachelor's or advanced degree in aerospace engineering, manufacturing engineering, materials engineering, mechanical engineering or physics.

• 5+ years of manufacturing engineering experience, including at least 3+ years hands-on work with solid rocket motors, energetic materials processing, or complex assembly in aerospace or defense.

Preferred Experience

• Bachelor's or Master's degree in Manufacturing Engineering, Mechanical Engineering, Chemical Engineering, Aerospace Engineering, Materials Science, or related field.

• 6–10+ years of manufacturing engineering experience, including at least 3+ years hands-on work with solid rocket motors, energetic materials processing, or complex assembly in aerospace or defense.
• Demonstrated success developing and scaling manufacturing processes from prototype to low-rate or rate production.

• Strong hands-on experience with propellant mixing/casting, composite filament winding or layup, liner/insulator processing, and propulsion hardware assembly.
• Proficiency in CAD (SolidWorks or NX), GD&T, tooling/fixture design, and process documentation.
• Familiarity with industrial automation, PLCs, robotics, or MES systems is a plus.
• Working knowledge of energetic materials safety and hazardous process manufacturing.

• Experience in fast-paced environments such as aerospace startups.
• Background supporting high-rate composite manufacturing, insensitive munitions practices, or vertical integration of propulsion hardware.
• Prior involvement in facility stand-up, equipment qualification, or production ramp activities.
• Familiarity with ITAR-controlled programs and classified manufacturing.

• Strong technical problem-solving and data-driven decision-making abilities.
• Excellent collaboration and communication skills across engineering, production, and quality teams.
• Ability to mentor junior engineers and contribute to process standardization.
• Safety-first mindset with attention to detail in high-consequence energetic environments.
• Proactive, hands-on approach with the ability to manage multiple priorities in a fast-paced setting.

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.