Senior Mechanical Design Engineer

About SerenX

SerenX is building the next generation of portable, autonomous defensive missile systems to protect America and our allies. Our mission is to deliver advanced, affordable air defense capabilities at a fraction of the cost and complexity of traditional systems.

We're an institutionally funded defense technology company performing work on U.S. Department of Defense contracts, with a founding team that includes Y Combinator alumni, former Special Operations leaders, and experienced aerospace engineers.

We design, build, fly, test, break, and improve our own hardware. We're looking for engineers who want to do the same.

The Role

We're hiring a Senior Mechanical Design Engineer to join our founding engineering team in Melbourne, Florida and take ownership of mechanical design for our SX family of interceptor airframes.

You'll work across the full hardware development lifecycle—from mechanical architecture and detailed SolidWorks design to prototype fabrication, integration, flight testing, failure analysis, and production-ready engineering.

This is not a CAD-only role. You'll work directly with hardware, collaborate with machinists and suppliers, participate in field testing, and see your engineering decisions validated in the real world.

Location: Melbourne, FL (On-site)

Employment: Full-time

Compensation: $125,000–$170,000 annually + equity

Reports to: CTO

What You'll Do

• Own mechanical architecture, detailed design, and master SolidWorks assemblies for current and next-generation interceptor airframes.
• Design lightweight structures, mechanisms, propulsion interfaces, actuator assemblies, and tightly integrated electromechanical systems.
• Package flight computers, cameras, sensors, batteries, power electronics, actuators, and wiring within highly constrained airframes.
• Collaborate with aerodynamic and CFD engineers to translate aerodynamic requirements into manufacturable, flight-ready structures.
• Own mechanical mass properties, including weight budgets, center of gravity, packaging trades, and structural considerations.
• Design components and assemblies using CNC machining, composites, additive manufacturing, injection molding, and other appropriate processes.
• Produce manufacturing drawings, GD&T, tolerance analyses, BOMs, and engineering documentation with configuration control.
• Apply design for manufacturing and assembly (DFM/DFA) to transition working prototypes toward repeatable production.
• Perform structural analysis and FEA, design test fixtures, and validate designs through physical testing.
• Participate directly in prototype assembly, integration, field testing, teardown, troubleshooting, and iterative redesign.
• Mentor junior engineers and technicians while helping establish the engineering practices of a growing aerospace company.

What We're Looking For

• B.S. in Mechanical Engineering, Aerospace Engineering, or a related technical discipline, or equivalent demonstrated engineering experience.
• 6+ years of mechanical product development, including meaningful ownership of hardware through design, fabrication, integration, and testing.
• Expert proficiency in SolidWorks, including complex assemblies, detailed drawings, and ASME Y14.5 GD&T.
• Experience designing lightweight structures, mechanisms, or tightly packaged electromechanical systems.
• Strong understanding of materials, manufacturing methods, fasteners, bonded joints, tolerance stackups, and mechanical failure modes.
• Practical experience with prototype fabrication, assembly, troubleshooting, and physical hardware testing.
• Ability to solve complex engineering problems from first principles, work independently, and make sound decisions with incomplete information.
• Willingness to work on-site in Melbourne, Florida and participate in field testing.

Particularly Valuable Experience

• Aerospace, UAVs, missile systems, experimental aircraft, spacecraft, high-performance robotics, or similarly demanding hardware.
• Composite structures, including carbon fiber, fiberglass, bonded assemblies, and composite-to-metal interfaces.
• Structural FEA using ANSYS, NASTRAN, Abaqus, SolidWorks Simulation, or similar tools.
• Experience taking aerospace hardware from rapid prototyping into low-rate production.
• PDM/PLM, engineering change management, BOM control, and configuration-managed hardware.
• Hands-on engineering projects outside of work, including rocketry, Formula SAE, robotics, motorsports, experimental aircraft, machining, or composites.
• Active Top Secret (TS) or TS/SCI security clearance strongly preferred for applicable programs, but not required for initial consideration.

Who Thrives Here

You enjoy engineering the complete physical system, not just an isolated component. You're comfortable moving between CAD, the machine shop, the integration bench, and the test field.

You take ownership of your designs, care about workmanship, and want to understand how hardware performs when it's actually built and operated.

You'll have substantial technical responsibility, direct access to company leadership, and the opportunity to shape the engineering culture and hardware architecture of a growing defense technology company.

Optional domestic and international customer or field travel may be available, subject to program and export-control requirements.

How to Stand Out

Show us what you've built.

We strongly encourage applicants to include 2–5 examples of hardware they personally designed, built, integrated, or tested. CAD screenshots, photographs, engineering drawings, test fixtures, and concise project portfolios are welcome, provided the material is unclassified and authorized for public disclosure.

We care more about demonstrable engineering ownership and real-world problem-solving than impressive program names on a résumé.

Export Control & Equal Opportunity

This position involves access to ITAR-controlled defense articles and technical data. Candidates must qualify as a U.S. person under 22 CFR 120.62.

SerenX is an equal opportunity employer. Employment decisions are based on qualifications, merit, and business needs, without unlawful discrimination based on any legally protected characteristic.

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