Our Mission
Castelion designs, tests, and manufactures next-generation military systems rapidly and at massive scale to deter future wars.
Peace Through Deterrence
Hardware Designed for Production at Scale
Castelion delivers the capabilities America needs to preserve peace through credible, non-nuclear deterrence. We build at the scale national security demands – optimizing every system for cost, manufacturability, and rapid deployment.
Hardware Rich.
Rapid Test and Iteration.
Designed for Scaled Manufacturing.
Affordable Hypersonic Weapons, Built Fast
At Castelion, speed and cost aren’t tradeoffs – they’re requirements. We vertically integrate core technologies to move faster, reduce risk, and control cost at scale. Every system is designed for manufacturability from day one, enabling rapid iteration and high-volume production. In today’s threat environment, speed matters. Affordability matters. We’re building with both.
Protecting Democracy
Our mission is rooted in the belief that freedom must be actively protected – through technological strength, strategic clarity, and national resolve. By restoring America’s ability to out-innovate and out-produce its rivals, we help ensure that the free world remains secure for generations to come.
Hardware Rich
Rapid Testing
Iterative Design
America Needs You!
Ready to get your hands on real hardware, own critical projects, and make your work count? Explore our open roles and help shape the future of defense.
Featured Positions
Choose your next adventure with Castelion.
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Apprentice Technician
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.- Torrance, CA
- Full time
- In-house
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Avionics Manufacturing Specialist
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.- Torrance, CA
- Full time
- In-house
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Construction Project Manager
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.- Torrance, CA
- Full time
- In-house
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Cybersecurity Engineer
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.- Torrance, CA
- Full time
- In-house
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Development Test Technician
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.- Torrance, CA
- Full time
- In-house
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Director of Communications
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.- Torrance, CA
- Full time
- In-house
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Electrical Engineer Intern – Fall 2025 (Avionics)
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.- Torrance, CA
- Full time
- In-house
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Electrical Technician
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.- Allen, TX
- Part-time
- In-house
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Embedded Software Engineer
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.- Torrance, CA
- Full time
- In-house
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Embedded Software Engineer Intern – Fall 2025 (Avionics)
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.- Torrance, CA
- Full time
- In-house
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Environmental, Health & Safety Engineer
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.- Torrance, CA
- Full time
- In-house
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Flight Software Engineer Intern – Fall 2025 (Avionics)
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.- Torrance, CA
- Full time
- In-house
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Flight Test Director
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.- Torrance, CA
- Full time
- In-house
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Flight Test Operations Manager
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.- Torrance, CA
- Full time
- In-house
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Lead Avionics Engineer – Flight Termination System
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.- Torrance, CA
- Full time
- In-house
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Lead R&D Technician
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.- Torrance, CA
- Full time
- In-house
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Senior Aerodynamics Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Avionics Hardware Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Avionics Harness Design Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Avionics Systems Integration Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Avionics Test Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Development Test Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Flight Software Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior FP&A Analyst
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.- Torrance, CA
- Full time
- In-house
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Senior IT Network Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior IT Service Desk Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior IT Systems Administrator
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!- Torrance, CA
- Full time
- In-house
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Senior Manufacturing Engineer – Mechanisms & Test
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- Torrance, CA
- Full time
- In-house
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Senior Manufacturing Engineer – Motor Case
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.- Torrance, CA
- Full time
- In-house
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Senior Materials & Process Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Mechanical Design Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior PCB Design Engineer
We are seeking a Senior PCB 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.- Torrance, CA
- Full time
- In-house
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Senior Propulsion Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior RF Hardware Design Engineer
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.- Torrance, CA
- Full time
- In-house
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Senior Software Engineer – Data Infrastructure
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.- Torrance, CA
- Full time
- In-house
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Senior Structural Engineer
As Senior Structural Engineer, you will lead structural and site design efforts across our expanding operational footprint. You’ll be responsible for designing and reviewing facilities that house energetic materials, propulsion systems, and advanced R&D efforts. This role requires deep technical expertise, strong field instincts, and experience designing for complex, hazardous environments.- Torrance, CA
- Full time
- In-house
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Senior Warhead Design Engineer
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.- Torrance, CA
- Full time
- In-house
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Site Development Lead
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.- Torrance, CA
- Full time
- In-house
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Software Engineer – Platform Integration
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.- Torrance, CA
- Full time
- In-house
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Software Infrastructure Architect
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.- Torrance, CA
- Full time
- In-house
Castelion News
March 31, 2025 Source: The Economist
Defence tech is blowing up Silicon Valley’s beliefs
In the back of an unmarked office building close to LAX, the main airport of Los Angeles, stands a rack of unarmed hypersonic missiles the size of small drainpipes. On February 6th a camouflaged truck ferried one away to New Mexico for a test launch with the US Air Force. Such activity used to be common in El Segundo, the LA neighbourhood that was once a hub of military spaceflight.
February 13, 2025
Source: WSJ
Startup Castelion Raises $100 Million for Hypersonic Strike Weapons
Silicon Valley’s enthusiasm for superfast weapons has picked up speed, with defense-tech startup Castelion raising $100 million through debt and equity to build hypersonic missile systems.
January 29, 2025
Castelion Announces Series A Funding
Castelion is excited to announce a $100M capital raise. This includes a $70M Series A, led by Lightspeed Venture Partners with participation from a16z, Lavrock Ventures, Cantos, First In, BlueYard Capital, and Interlagos, and $30M in Venture Debt financing provided by Silicon Valley Bank, with final close expected in February. With this funding we will further accelerate test cycles, scale our mass production facilities, and execute a capability demonstration of our first hypersonic weapon. These efforts will move us faster and closer to regaining a decisive advantage and thereby creating credible deterrence.
March 11, 2024
Source: Reuters
Hypersonic weapon startup Castelion has first prototype missile test
Castelion, a startup trying to build a hypersonic weapon for the Pentagon, tested its system for the first time, it told Reuters on Monday, as a growing group of small hypersonic arms makers challenge large defense contractors with less expensive, rapidly produced products.