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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Automation and Controls Engineer
The Automation and Controls Engineer will design, build, and commission robust manufacturing systems for production of hypersonic-flight components. Success requires the practical application of engineering principles to design, build, test, and integrate process equipment and technologies within our production line. We are seeking a hands-on problem solver with strong expertise in electro-mechanical system design and automation systems, as well as experience working with machinery and production environments. The key to excelling in this position is the effective application of mechanical, electrical, and control systems expertise to enable our manufacturing processes.- 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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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 – Summer 2026 (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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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 – Summer 2026 (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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Engineering Manager, Flight Software
As the Software Engineering Manager for Flight Software, you will lead and contribute to the development of flight software for Castelion’s advanced missile systems. This is a hands-on technical leadership role, you’ll architect, review, and write production-quality code while building the team, software infrastructure, and processes needed to deliver certifiable, flight-ready systems. You’ll guide the roadmap from prototype to certified production software, ensuring safety, reliability, and client confidence. Early on, you’ll be deeply involved in software architecture, code reviews and integration; as the program scales, you’ll grow and mentor a team around those foundations.- 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 – Summer 2026 (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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Head of Flight Software
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.- Torrance, CA
- Full time
- In-house
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Head of Government Affairs
The Head of Government Affairs will be responsible for leading Castelion’s engagement with policymakers, regulators, and industry stakeholders across the federal, state, and local levels. This individual will develop and execute strategies to ensure Castelion’s priorities are understood by decision-makers, regulatory hurdles are anticipated and addressed, and the company’s policy environment enables rapid innovation and scaling.- Torrance, CA
- Full time
- In-house
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Information Systems Security Manager (ISSM)
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.- 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 Mechanisms Engineer
Castelion is seeking a Lead Mechanisms Engineer to drive the design, development, and integration of the actuation and mechanical systems that enable control across our missile programs. In this role, you’ll lead a small, cross-functional team owning the design, integration, and validation of fin control actuators, thrust vectoring mechanisms, release devices, and other mission-critical mechanical subsystems.- 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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Materials & Process Engineer
Castelion is growing our Engineering team to support the development of high-performance materials for hypersonic flight. The ideal candidate will have a comprehensive understanding of materials engineering, with a focus on data-driven process development and optimization. In this role you will have the opportunity to work on a wide range of complex and technically challenging tasks including process development for high-temperature composite materials, and characterization and analysis for different material systems in relevant operational environments. This scope includes support to the manufacturing process development for production of high-performance TPS materials and executing material test campaigns to validate new materials and process changes. This role requires strong problem-solving skills and the ability to collaborate effectively across the materials, manufacturing, and vehicle engineering teams.- Torrance, CA
- Full time
- In-house
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Mission Integration Engineer
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.- Torrance, CA
- Full time
- In-house
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Principal Manufacturing Engineer
Castelion is seeking a principal manufacturing engineer to join our Radar development team. In this role, you will own the end-to-end transition from prototype to full-scale production. You will architect and implement manufacturing processes to achieve aggressive production cost, quality, and delivery targets.- Allen, TX
- Full time
- In-house
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R&D Technician – Hypersonics (Welding, Machining, Composites)
Were looking for a hands-on R&D Technician to support prototype fabrication, assembly, and test of hypersonic systems. You’ll work directly with engineers to translate designs into parts and assemblies – focusing on precision manual machining, TIG/MIG welding, and composite layup and repair – in a fast-paced R&D 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 Hardware Design Engineer
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.- 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 – Machining
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.- 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 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 Teamcenter PLM Developer
Castelion is seeking a high performing Teamcenter PLM Developer to lead the architecture, implementation, and maintenance of PLM across engineering, manufacturing and supply chain. In this role, you will be responsible for supporting, configuring, and enhancing Teamcenter (Siemens PLM) and other manufacturing software applications, ensuring seamless integration across multiple engineering and manufacturing systems. The ideal candidate will have strong experience in Teamcenter administration, customization, and integration, as well as a deep understanding of manufacturing processes and software tools.- 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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Sourcing Specialist
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.- Torrance, CA
- Full time
- In-house
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Strike Weapons Program Manager
As a Strike Weapon Program Manager, you will lead the execution of advanced hypersonic weapon programs from initial concept through delivery, serving as the primary interface with U.S. Government customers and internal engineering teams. You will own program schedules, contractual commitments, and mission success, driving efforts from proposal through design, integration, flight test, and fielding.- Torrance, CA
- Full time
- In-house
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Weapons Integration Engineer
As a Weapons Integration Engineer you will be part of the team that ensures Castelion weapon systems integrate seamlessly with ground launchers, tactical/multi-role aircraft, and future systems. You will own platform integration efforts from early concept and capability studies through prototype development, test, and operational deployment – collaborating with propulsion, avionics, GNC, software, flight test, and manufacturing teams to deliver mission-ready solutions.- 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.