Careers

We are seeking an experienced Accounts Payable (AP) Clerk to join our growing finance team. This role will directly support our Accounting Manager and be responsible for ensuring accurate and timely processing of vendor invoices, payments, and employee expense reports. The ideal candidate is detail-oriented, organized, and thrives in a fast-paced, dynamic environment where accuracy and accountability are critical.

As Construction Project Manager, you will be responsible for planning and executing the build-out of new operational and R&D sites for Castelion. You will work closely with internal stakeholders, contractors, architects, and local authorities to ensure our facilities are delivered on time, within budget, and aligned with our mission needs. This role requires a high level of autonomy, field presence, and the ability to thrive in fast-moving, ambiguous environments.

We’re hiring a Cybersecurity Engineer with experience securing systems in regulated, compliance-heavy environments. If you’re well-versed in frameworks like NIST SP 800-171, CMMC, or ISO 27001, and you know how to turn complex regulatory requirements into practical, enforceable security controls, you’ll feel right at home here.

Were hiring a Director of Communications to lead Castelions storytelling and external communications efforts. This role is responsible for crafting and amplifying our public voice across leading media outlets and key external stakeholders.

We are seeking a skilled Facilities Technician to support the upkeep, maintenance, and safe operation of our facilities. This hands-on role involves performing a wide range of tasks, including routine maintenance, repairs, and general facility upkeep across systems such as plumbing, electrical, HVAC, and carpentry. The ideal candidate will demonstrate a proactive approach to problem-solving, and the ability to work independently within a fast-paced, mission-driven environment.

We are seeking a highly capable Flight Test Director to lead the planning, coordination, and execution of weapon development flight test events. In this role, you will be responsible for ensuring that every test is conducted safely, legally, and in alignment with engineering objectives. You will serve as the central authority for final test readiness, go/no-go decisions, and on-site leadership during test campaigns.

The Flight Test Operations Manager is the mission enabler for all field test activity. You’ll own the end-to-end logistics and ground operations that ensure every test campaign launches on time, safely, and without friction. From site prep and transportation to emergency planning and team sustainment, you’ll make sure people, equipment, and assets are exactly where they need to be.

The ISSM’s primary function serves as a principal expert and manager on all matters, technical and otherwise, involving the security of information systems under his/her purview. Primary support will be working within Special Access Programs (SAPs) supporting Department of Defense (DoD) agencies, such as HQ Air Force, NAVY, Army, DARPA, etc. The position will provide “day-to-day” support, oversight, and maintenance for Collateral, Sensitive Compartmented Information (SCI) and Special Access Program (SAP) activities.

As a Mission Integration Engineer, you will be the primary technical liaison between Castelion and our government customers, supporting the integration of advanced weapons systems into operational environments. You will drive the entire lifecycle of weapons programs, from early capability studies through prototype development, test, and operational deployment.

We’re seeking a highly analytical, detail-oriented Senior FP&A Analyst to join our lean, high-impact team. In this role, you will help drive financial visibility and decision-making across a rapidly scaling defense hardware company. You will support planning, forecasting, and performance analysis to enable fast, confident decisions by our leadership and engineering teams.

We are seeking a highly skilled and security-cleared Senior Network Engineer to design, implement, manage, and maintain complex network infrastructures supporting our mission-critical systems. The ideal candidate will bring deep technical knowledge of networking protocols and architecture, an understanding of cybersecurity requirements (e.g., DISA STIGs, RMF), and proven experience operating in a fast paced, growing organization.

We’re looking to hire a Senior IT Service Desk Engineer who thrives in fast-paced, high-pressure environments and brings strong technical acumen paired with a people-first attitude. This role is ideal for individuals with experience supporting, engineering or aerospace firms, DoD contractors, or high-growth startups. If you’re the kind of person who stays cool when things go down and can turn a stressful IT moment into a positive interaction, we want to meet you.

We are seeking a highly skilled and security-focused Senior IT Systems Administrator to join our team. In this role, you will be expected to be a leader in the design, implementation, maintenance, and security of critical IT infrastructure in compliance with DoD and industry standards. We want to give you the autonomy you need to shine and show what you’ve got! Ideally, youll thrive as someone who is able to handle senior level systems projects end-to-end with minimal oversight, while still delivering high quality work!

As a Shipping and Receiving Specialist, you’ll play a critical role in our supply chain operations. We’re looking for a hands-on, detail-oriented professional who thrives in a fast-paced, high-standards environment. This role requires precision, accountability, and a solutions-oriented mindset to ensure materials are received, processed, and shipped accurately and efficiently.

As a Sourcing Specialist, you will be integral in working with the cross-functional groups defining, designing, building, and testing Castelion vehicle and missile subsystems. This role requires an established supply chain professional with breadth to engage new suppliers and program sourcing strategies to align with short term development schedules and long term sourcing focus for low cost, sustainable supply chain plans. We seek intelligent, collaborative, and driven leaders who are passionate about problem-solving and eager to lay the groundwork for a team to contribute to an extraordinary mission. If you thrive in challenging environments and are excited by the prospect of making a tangible impact, we want to hear from you.

As the Supply Chain Manager, you will be integral in working with the cross-functional groups defining, designing, building, and testing Castelion subsystems. This role requires an established supply chain professional with breadth to engage with engineering to execute the necessary program sourcing strategies to align with short term development schedules and long-term sourcing focus for low cost, sustainable supply chain plans. We seek intelligent, collaborative, and driven leaders who are passionate about problem-solving and eager to lay the groundwork for a team to contribute to an extraordinary mission. If you thrive in challenging environments and are excited by the prospect of making a tangible impact, we want to hear from you.

Castelion is seeking a detail-oriented and highly motivated Apprentice Technician to join our manufacturing team. In this role, you will support the design, setup, execution, and documentation of tests on hypersonic missile components and systems during the development phase. You will work closely with design and manufacturing engineering teams to ensure products meet rigorous performance, reliability, and safety standards.

Castelion is looking for an Avionics Manufacturing Specialist, reporting to the Head of Avionics, to support the development of the systems that will be required for the design and build of long-range hypersonic strike vehicles. This will be a full-time, exempt position located in our El Segundo facility. As an Avionics Manufacturing Specialist, you will work closely with our engineering teams to execute highly technical electrical builds for our research vehicles, assist in advancing designs, and play a critical role in defining and maturing manufacturing, assembly and integration processes.

Castelion is seeking an accomplished Composites Material Technician to help advance cutting-edge manufacturing processes for our hypersonic products. In this role, the Composites Material Technician will work closely with the materials engineering team to define and execute manufacturing processes for the fabrication of ultra-high temperature ceramic matrix composite (CMCs) materials. The role will require; the mastering of complex processes such as chemical vapor deposition (CVD), operation of high-temperature furnaces and ovens, and the production of prepreg materials.

Castelion is seeking a detail-oriented and highly motivated Development Test Technician to join our manufacturing team. In this role, you will support the design, setup, execution, and documentation of tests on hypersonic missile components and systems during the development phase. You will work closely with design and manufacturing engineering teams to ensure products meet rigorous performance, reliability, and safety standards.

We’re looking for a highly skilled, hands-on Electrical Technician to support our engineering team during off-hours, ideally nights or weekends. This is a very part-time role, perfect for someone with a steady hand and a sharp eye who enjoys diving into detailed electrical work.

We are seeking an experienced Environmental, Health, and Safety (EH&S) Engineer to join our team in a fast-paced, high-volume manufacturing environment. The ideal candidate will be responsible for ensuring the safety and environmental compliance of our manufacturing processes while driving continuous improvement in health, safety, and environmental performance. This role requires a strong understanding of process safety management, hazard analysis, regulatory compliance, and best practices for industrial safety in the energetics sector.

Castelion is seeking a detail-oriented and highly motivated Lead R&D Technician to join our manufacturing team. In this role, you will support the design, setup, execution, and documentation of tests on hypersonic missile components and systems during the development phase. You will work closely with design and manufacturing engineering teams to ensure products meet rigorous performance, reliability, and safety standards.

Castelion is seeking an expert in composites manufacturing to help define and scale our in-house composites manufacturing processes from raw material to flight parts. This will include scaling our current ceramic matrix composite (CMC) production line and supporting day to day production of all composite vehicle components including nozzles, aeroshells, fins, etc. This role will report directly to Castelion’s Head of Manufacturing and work closely with the engineering leadership team to identify and eliminate roadblocks to achieving long term company goals. As an early hire on the manufacturing team, this role will be highly influential in defining manufacturing and production strategy and culture at Castelion.

A a Senior Manufacturing Engineer – Machining, you will lead the rapid expansion of Castelion’s in-house machining capabilities, enabling our mission to fly early and often. This role is critical to our ability to quickly iterate, test, and deliver hardware. You’ll be responsible for standing up infrastructure, processes, and tools that accelerate prototype part delivery – minimizing the time from design release to parts in hand. Beyond rapid prototyping, you’ll also define best practices for design for manufacturability (DFM) of machined components and contribute to the long-term machining strategy for both prototyping and production environments.

Castelion is looking for an expert in the development and maturation of complex mechanical assemblies. This position will be tasked with bringing a mechanical product from conception to full scale production

Castelion is seeking an expert in the manufacture and design of high performance solid rocket motor cases. This role will work closely with design engineering and technician teams to build and execute on testing and validation efforts to keep pace with the research and development timetable of our products. You will be apart of a team responsible for serving as a critical node in implementing feedback from testing and validation efforts, streamlining designs and implementing manufacturing changes to quickly mature our products for flight testing and production. Desire for product and process ownership is a must in this role.

We are seeking an experienced and highly motivated Site Development Lead to oversee the planning, design, and execution of site development projects from concept to completion. This leadership role requires a strategic thinker with strong technical knowledge and a proven ability to manage a team while ensuring the project exceeds company goals, is completed on time, and stays within budget. The Site Development Lead will play a key role in coordinating with internal teams, external partners, and stakeholders to ensure the success of critical development projects.

Castelion is seeking driven and talented Flight Software Engineer Interns for Fall 2025. You’ll help design, build, and test the real-time embedded software that powers our next-generation missile systems, ensuring they operate reliably under extreme conditions. You’ll work alongside experienced flight software, GNC, systems, and hardware engineers to design, implement, test, and debug critical flight code. You won’t be writing throwaway code; your contributions will directly support flight tests, hardware-in-the-loop simulation, and real mission deployments.

As an Embedded Software Engineer you will be at the forefront of creating, developing, and testing the software that drives and simulates our flight systems. Your role involves close collaboration with fellow Castelion engineers across software and hardware domains to implement and debug software across the entire technology stackfrom applications and operating systems to networking, firmware, and simulationensuring complete mission success. We seek intelligent, collaborative, and driven engineers who are passionate about problem-solving and eager to contribute to an extraordinary mission. If you thrive in challenging environments and are excited by the prospect of making a tangible impact, we want to hear from you.

Castelion is seeking an Embedded Software Engineer to architect, implement, and harden software running on resource constrained, mission critical systems. You’ll write low-level C and Rust, accelerate workloads with CUDA, and own secure processing paths (crypto, secure boot, key management) from concept through field test. You’ll collaborate closely with electrical, systems, and test teams to bring new hardware online fast and keep it reliable.

Castelion is seeking motivated and talented embedded software engineering interns for 2025. Youll help create the software that drives and simulates our missile systems, from low-level firmware on microcontrollers to high-level integration and testing tools. Youll work alongside experienced embedded, hardware, and flight systems engineers to design, implement, test, and debug real systems in the loop. You wont be writing throwaway code; your contributions will directly support our rapid prototyping and real-world tests.

Position Overview: Castelion is seeking driven and talented Flight Software Engineer Interns for 2025. You’ll help design, build, and test the real-time embedded software that powers our next-generation missile systems, ensuring they operate reliably under extreme conditions. You’ll work alongside experienced flight software, GNC, systems, and hardware engineers to design, implement, test, and debug critical flight code. You won’t be writing throwaway code; your contributions will directly support flight tests, hardware-in-the-loop simulation, and real mission deployments.

As the Head of Flight Software Engineering, you will lead the development of innovative flight software for Castelion’s advanced missile systems, playing a critical role in achieving our mission of peace through deterrence. This role demands a highly motivated individual with deep expertise in flight software development, a passion for mentoring teams, and a commitment to deliver robust, mission-critical systems. You will oversee all aspects of flight software design, development, integration, and testing, ensuring that Castelion’s cutting-edge systems perform reliably under the most demanding conditions.

Interested in Castelion but not sure which job to apply for? Drop your resume here and we can help you figure it out.

As the Lead Avionics Engineer specializing in Flight Termination Systems (FTS), you will be responsible for the design, development, testing, and qualification of systems that ensure the safe termination of a flight if it deviates from its planned trajectory. You will work with both hardware and software components, as well as coordinating with various key stakeholders.

We’re looking for a Lead Mechatronics Engineer to guide the development and integration of actuation systems across our missile programs. In this role, you’ll lead a small, cross-functional team that owns the design, integration, and validation of servo systems providing fin control, thrust vector control, and other critical actuation functions.

Castelion is seeking a hands-on, high-agency Mechanical Engineer excited to take ownership of real flight hardware and grow alongside a fast-moving team. You will work on the design, fabrication, and integration of critical flight structures and mechanisms across Castelion’s hypersonic vehicles. This role is ideal for someone who thrives in fast-paced environments, learns quickly, and wants to see their work go from concept to flight in weeks-not years. You’ll be empowered to take on meaningful responsibilities immediately. This is a rare opportunity to grow as a full-stack engineer while working on hardware that matters.

We are seeking a Senior Aerodynamics Engineer to lead aerodynamic analysis and design for our high-performance missile and vehicle systems. This role is critical in shaping the aerodynamic performance of our systems from concept through flight test. You will work hands-on with multidisciplinary engineering teams to design, analyze, and validate aerodynamic solutions in a rapid hardware-driven environment.

As a Senior Avionics Hardware Engineer, you will play a vital role in designing, testing, and optimizing hardware systems for cutting-edge hypersonic missile avionics projects. You will contribute to the development and production of high-quality, reliable hardware components for hypersonic missiles. This role provides a hands-on opportunity to work alongside experienced engineers, gain practical experience, grow your technical skills in a fast-paced and innovative environment, and experience a rapid cadence of test flights where your hardware will be tested in the field.

We are seeking a Senior Avionics Harness Design Engineer to lead the design, development, and integration of electrical harnessing across our missile and vehicle systems. This engineer will play a critical role in ensuring robust, manufacturable, and high-reliability electrical connectivity throughout the system. You will partner closely with avionics, power, structures, and propulsion teams to deliver mission-critical hardware in a fast-paced, hardware-rich environment. You will additionally support avionics and harness integration at the system and vehicle levels.

Join Castelion and play a pivotal role in advancing the development of next-generation hypersonic missile systems. As an Avionics Systems Engineer, you’ll be part of a cross-disciplinary team responsible for the seamless integration of avionics systems across design, development, testing, and operations. You’ll directly impact mission-critical systems that shape national defense and peace through deterrence.

We are looking for a Senior Avionics Test Engineer to own the validation and performance characterization of our control actuation systems the critical interface between control commands and physical motion on our flight vehicles. You will lead the development of rigorous test infrastructure, design and execute test campaigns, and help define the performance envelope of every actuator that flies.

We are seeking a Senior Development Test Engineer to drive testing and validation of missile and vehicle systems in a fast-paced, hardware-rich environment. You will be responsible for designing and executing tests, analyzing results, and providing actionable insights that directly inform design and performance optimization. This is a hands-on role that requires technical depth, resourcefulness, and strong cross-team collaboration.

As a Senior Flight Software Engineer, you will play a key role in designing, developing, and testing flight software that powers these advanced systems. You’ll work closely with multidisciplinary teams to deliver high-performance, real-time embedded software that operates reliably under extreme conditions.

We are seeking a Senior Hardware Design Engineer to lead the design, development, and delivery of smart circuit boards that form the brain of our missile systems. You’ll be responsible for everything from initial architecture through layout, manufacturing, test, and integration. You’ll work closely with electrical, firmware, and mechanical engineers to deliver tightly integrated, high-reliability systems. This role is ideal for someone who has designed and delivered complex smart PCBs – with embedded microcontrollers, high-speed interfaces, and networking components – ideally in constrained or mission-critical environments.

Castelion is seeking a Senior Materials & Process Engineer to develop and validate epoxy bonding processes for our long range, precision strike hypersonic missiles. This role is directly reporting to our Head of Manufacturing and will also work closely with our Materials and Design Engineering teams to test and integrate epoxy bonding processes. A strong understanding of epoxy adhesives and their interactions with other materials is a must as this person will serve as the subject matter expert for the entire organization.

Castelion is seeking a high output Senior Mechanical Design Engineer with a full stack, Responsible Engineer mindset and experience shipping flight hardware. This person will be responsible for critical flight structures and mechanism design and build efforts for Castelions hypersonic vehicles. The Senior Mechanical Engineer will work closely with a fast-moving team of peers and engineering leadership to ensure mission-critical hardware is delivered on time and meets demanding technical performance. A successful candidate will have significant experience delivering high-performance, mass-constrained hardware in a rapid development environment.

The Senior Propulsion Engineer’s primary responsibility is the design of solid rocket motor primary and secondary structures, along with propulsion components, with an emphasis on schedule, affordability and scale.

Castelion is seeking a high output RF Engineer to lead the design and development of RF communications hardware & telemetry systems (both front end and back end) for Castelion hypersonic test platforms and weapon systems. In this role you will be responsible for initial vehicle telemetry systems for Castelion hypersonic test flights and lead software defined radio (SDR) product development for Castelion weapon systems. The role will coordinate closely with Castelions engineering leadership and report directly to the Head of Avionics. A successful candidate will have significant experience delivering highly manufacturable RF/avionics hardware with extreme reliability for mission-critical applications in a fast-paced environment.

Were looking for a hands-on software architect who can design and build Castelion’s mission data infrastructure from the ground up. Our hardware generates terabytes of telemetry and test data across manufacturing, lab, and flight environments. You will be the first engineer to architect this company-wide system, from ingestion through visualization, ensuring our hardware teams, technicians, and analysts can get the right data at the right time. This role is not about wiring together existing cloud tools, its about inventing the architecture, designing core services, and implementing the systems that will define how Castelion handles data for years to come.

Castelion is designing and building next-generation hypersonic weapon systems that restore stability through credible deterrence. We are seeking a hands-on, mission-driven Ordnance Engineer to lead the design, development, and integration of ordnance systems across our hypersonic vehicles.

Castelion is seeking a Software Engineer Platform Integration to develop embedded and integration-layer software that enables Castelion’s hypersonic weapon systems to interface with a variety of airborne and ground-based launch platforms. This includes implementing Universal Armament Interface (UAI) protocols for tactical aircraft and supporting Fire Control System (FCS) integration for ground-based launchers. You will contribute to the full lifecycle of integration, from protocol implementation and system communication to simulation, testing, and mission deployment. The ideal candidate is a generalist with strong software fundamentals, experience working across embedded and systems layers, and a drive to build real-world, high-performance systems.

As a Software Infrastructure Architect you will be at the forefront of architecting, developing, and testing the software that drives data infrastructure. Your role involves close collaboration with fellow Castelion engineers across software and hardware domains to implement and debug data infrastructure software across the entire technology stack from automation of testing to management of lab, test, and flight data ensuring complete mission success. We seek intelligent, collaborative, and driven engineers who are passionate about problem-solving and eager to contribute to an extraordinary mission. If you thrive in challenging environments and are excited by the prospect of making a tangible impact, we want to hear from you.