Senior Mechanical Design Engineer

About the role

This position centers on the mechanical realization of nuclear power systems for space and planetary surfaces, where you will serve as the Responsible Engineer for specific hardware elements. You will own the complete lifecycle of your assigned subsystems, guiding components from initial clean sheet conceptualization through detailed design, prototyping, verification testing, and final integration. Success in this role requires driving system-level trade studies and layout decisions while maintaining strict adherence to nuclear and spaceflight requirements. You will act as a primary interface between mechanical design and disciplines such as nuclear, thermal, and manufacturing to ensure cohesive system integration. A core part of this position involves defining thermal and mechanical interfaces, managing configurations in CAD, and ensuring designs are both functional and manufacturable. You will lead design reviews and develop the necessary work instructions and documentation to support production and testing activities. Ultimately, your work will directly influence how hardware performs in the unique environments of Earth orbit, the Moon, and Mars.

Key facts

What you'll do

• Own a subsystem and related hardware as part of the larger space nuclear system, driving the design from concept to production.
• Perform system-level layout, requirements definition, and decomposition, then defend design decisions across all phases from concept through Critical Design Review and beyond.
• Create and manage CAD models, generate production drawings, and develop DFMEA documentation to ensure robust design outputs.
• Lead cross-discipline alignment sessions and conduct trade studies to evaluate configurations, packaging, and interface strategies.
• Coordinate closely with nuclear, thermal, structural, manufacturing, and quality teams to ensure the system architecture meets mission and product requirements.
• Develop clean sheet designs and see them through hardware procurement, development testing, and qualification testing activities.
• Support the preparation of design reviews and the planning of integration and test activities, including defining the necessary manufacturing plan and work instructions.
• Analyze system interactions using first principles to evaluate thermal and mechanical performance under expected mission conditions.
• Maintain strict requirements traceability from high-level objectives down to detailed component specifications and test verifications.
• Document design rationales, assumptions, and limitations to support future reviews, audits, and knowledge transfer.

Requirements

• Hold a Bachelor's degree in mechanical engineering, aerospace engineering, or another physics-based field relevant to system design.
• Possess a minimum of 3 years of hands-on experience in mechanical design for space systems or related high-tech hardware development.
• Demonstrate advanced proficiency with CAD software such as NX or CATIA, along with experience using Product Lifecycle Management (PLM) tools.
• Have a proven ability to manage engineering configurations and produce detailed drawings suitable for manufacturing and inspection.
• Show familiarity with the unique constraints and requirements associated with nuclear systems and space-qualified hardware.
• Exhibit strong foundational knowledge in fluid systems and solid mechanics to evaluate component and subsystem behavior.
• Bring a track record of initiative that results in high-impact contributions and clear return on investment for complex projects.
• Apply broad knowledge of materials science, including material selection criteria specific to demanding nuclear and space environments.
• Conduct complex design trades and first-order engineering analyses while transparently documenting limitations and associated design risks.
• Utilize very strong design skills, including GD&T, to translate concepts into detailed drawings that can move into production.
• Be prepared to work extended hours, including weekends, to meet critical project milestones and support test campaigns.
• Be willing and able to obtain and maintain a security clearance as required by U.S. government contracts.

Nice to have

• Hold a Master's degree or Ph.D. in mechanical engineering, aerospace engineering, or a related physics-based discipline.
• Have direct experience designing, analyzing, or integrating nuclear systems for space applications.
• Have led project teams or research efforts where you guided technical direction and cross-functional collaboration.
• Demonstrate advanced project management capabilities and the ability to manage competing priorities in a fast-paced environment.
• Communicate complex technical information clearly to diverse audiences, including non-specialists, during reviews and discussions.
• Understand fundamental principles in both fluid systems and solid mechanics at a level that supports system-level troubleshooting.
• Maintain a documented history of initiative and high-impact contributions in previous roles or research.
• Show broad familiarity with material properties and selection processes, particularly for components exposed to nuclear radiation.
• Perform system sizing, trade studies, and analytical modeling while clearly articulating the boundaries of your analysis.
• Possess highly developed design skills and substantial GD&T experience to take prototypes into detailed manufacturing.

Practical notes

• The position is based in Los Angeles, California, at a new 322,000 square foot facility designed to support R&D, production, and team collaboration.
• The location provides access to major freeways including the 405, 105, and 110, situating the team within a growing tech ecosystem in Los Angeles.
• Antares is backed by over $600M in venture capital and more than $11M in government funding, providing stability and resources for long-term mission execution.
• The company was formed in 2023 and draws talent from organizations such as SpaceX, The White House, MIT, Rigetti Computing, The Air Force, General Atomics, Relativity Space, Ursa Major, and National Laboratories including Los Alamos, Idaho, and Oak Ridge.