Senior Mechanical Engineer

Muon seeks a Senior Mechanical Engineer to own the mechanical direction of a spacecraft subsystem or mission from requirements definition to installation on the launch vehicle. The ideal candidate can go deep on design while carrying a "systems mindset" — a force multiplier who collaborates across disciplines to arrive at an elegant, well-balanced design. You'll start from Muon's platform building blocks, tailor and design hardware to meet mission needs, and pull in the right stakeholders (structural, thermal, electrical, systems) at the right times to deliver on time.

Being an early-stage company with small teams, breadth is essential: you'll have touch points across engineering, production, and program management.

As a Senior Mechanical Engineer, you'll own the design of spacecraft subsystems from concept through flight — spanning work such as payload accommodations and primary structures, deployables and solar arrays, and precision mechanisms. You'll take technical responsibility for complex assemblies, set the design approach, and drive them through analysis, build, integration, and test on fast-moving mission timelines.

Beyond your own designs, you'll act as a technical anchor for the broader mechanical team — reviewing others' work, resolving the hardest trade-offs, mentoring earlier-career engineers, and partnering across disciplines (structures, thermal, avionics, propulsion, GNC) to keep the vehicle integrated and on schedule.

This position is hybrid and requires working on-site in our San Jose, CA office three days per week.

• Own the end-to-end mechanical design of one or more spacecraft subsystems, from requirements and concept through CAD, flight build, and on-orbit verification.
• Set the design and analysis approach for complex assemblies, making and defending key engineering trade-offs with limited oversight.
• Lead design reviews and serve as a reviewer/approver for other engineers' designs and analyses.
• Drive integration and test of your hardware, and troubleshoot issues through root cause during build, qualification, and mission operations.
• Partner with the dedicated structural and thermal groups on detailed analysis, and coordinate across adjacent disciplines to keep the vehicle integrated.
• Mentor engineers, raise the team's technical bar, and influence design standards and best practices beyond your immediate scope.

• 8+ years of experience designing, building, and testing high-reliability hardware
• B.S. or higher in Mechanical Engineering, Aerospace Engineering, or a related field
• Proficiency in CAD (Solid Works preferred) for medium-to-large assembly design and management
• Mastery of drawings, GD&T, BOMs, FAIs, tolerance budgets, and mass budgets
• Experience with ECO/DCO processes and PLM systems
• Demonstrated proficiency leading mechanical design for complex electromechanical systems
• Experience managing external vendors for part prototyping and development
• Excellent communication, presentation, and cross-functional coordination skills

• Deep design experience in one or more of: spacecraft structures and mission integration; deployables and solar arrays; or precision mechanisms.
• Experience owning a subsystem across its full lifecycle, including flight heritage or on-orbit hardware.
• Fluency with first-order structural/thermal analysis and hand-offs to dedicated analysis teams.
• Experience leading design reviews and defining design standards or processes.
• Hands-on background in integration, test, and anomaly resolution of flight hardware.
• Familiarity with solar array or electrical/power-system design (not required at this level).
• Experience mentoring or technically leading a small team of engineers.

The salary range for this role is $173,000 -…