Senior Structures Engineer

About Us About UsAt Antares, our long-term mission is to make clean energy abundant from Earth to the Asteroid Belt. We’re fueled by the belief that advanced nuclear energy can strengthen our military, solve the climate crisis, elevate global living standards, and expand humanity's presence in outer space. To achieve our mission, we’re building mass-producible, inherently safe, deployable microreactors that can be used terrestrially, underwater, and in space.The Antares team hails from SpaceX, the White House, the Pentagon, the Department of Energy, MIT, Rigetti Computing, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Idaho, Oak Ridge, Los Alamos, and Savannah River. Antares has raised over $600M in venture capital from top-tier investors and has hundreds of million-dollars on contract with the military services, NASA, and the Department of Energy. About the Role As a Senior Structures Engineer, you'll lead the design, analysis, and development of critical reactor structures, including the core restraint mechanism, control drum support and mounting systems, primary heat exchanger vessel supports, and other safety-significant structural components. You will ensure these systems meet structural, thermal, and functional performance requirements throughout development, testing, and operation. You will work closely with cross-functional teams to develop first-of-a-kind hardware in a highly constrained, multidisciplinary design environment while supporting prototype fabrication, testing, qualification, and deployment. The ideal candidate has extensive experience designing complex structural systems in regulated industries and is passionate about solving challenging engineering problems from concept through hardware realization. Roles and Responsibilities Perform thermal, mechanical, and structural analyses to support the sizing, layout, and optimization of reactor structural components, including the core restraint system, control drum mounting, primary heat exchanger (PHX) vessel supports, and other structural systems as required. Define system architecture, operating limits, design margins, and concepts of operation (CONOPS) to ensure reliable performance across all operating conditions. Develop engineering documentation, including calculations, specifications, interface definitions, design reports, and technical justifications to support design reviews, verification, and licensing activities. Lead the design, fabrication, and execution of component- and system-level testing by developing test articles, test fixtures, instrumentation plans, and validation procedures to demonstrate performance, durability, and life‑cycle reliability. Collaborate cross-functionally with reactor, thermal, manufacturing, licensing and procurement teams to ensure successful integration of structural systems into the overall reactor design. Support supplier selection, technical evaluations, design reviews, and the resolution of manufacturing, assembly, and installation issues. Present technical work at internal and external design reviews and provide technical leadership throughout the design, analysis, testing, qualification, and deployment lifecycle. Basic Qualifications Bachelor's degree in Mechanical Engineering, Aerospace Engineering, Nuclear Engineering, or a related engineering discipline. 5+ years of professional experience designing, analyzing, and developing structural systems for demanding engineering applications. Experience in structural design, including hand calculations, material selection, bolted and welded joint design, load path development, and thermo‑mechanical trade studies. Experience using finite element analysis (FEA) tools to evaluate structural performance, stress, deformation, fatigue, and thermal loading. Knowledge of structural design principles, materials, bolted and welded joints, and load path development. Demonstrated ability to work effectively on multidisciplinary engineering teams and communicate technical concepts to a broad range of technical and non-technical stakeholders. Preferred Skills & Experience Master's degree or higher in Mechanical Engineering, Aerospace Engineering, Civil Engineering, Nuclear Engineering, or a related engineering discipline. Demonstrated expertise in structural design, including hand calculations, material selection, bolted and welded joint design, load path development, and thermo‑mechanical trade studies. Proficiency with structural analysis and simulation tools such as ANSYS Mechanical, Abaqus, Nastran, or equivalent finite element analysis (FEA) software. Strong understanding of material behavior and structural design considerations, including thermal stresses, creep, fatigue, fracture, buckling, corrosion, and high-temperature material performance. Experience designing hardware in accordance with ASME Boiler & Pressure Vessel Code, AISC, ACI, AWS, NASA, or other applicable structural and mechanical design standards. Experience serving as a Technical Lead or Responsible Engineer, leading multidisciplinary engineering efforts from concept development through design, testing, qualification, and hardware deployment. Experience developing first-of-a-kind hardware in highly regulated industries such as nuclear, aerospace, defense, energy, or other safety‑critical applications. Additional Requirements Ability to work long hours and weekends as necessary to support critical milestones. Culture Think in Systems - Energy and Defense are complex ecosystems with numerous stakeholders with competing priorities, conflicting policies, perverse incentives, and emergent and path‑dependent properties. First principles thinking alone is insufficient. Think probabilistically and then take action. "If you want to be certain, then you are apt to be obsolete." Over‑optimizing the components often degrades the system Obsess over the End User - The customer and end user are often not the same. We will never build globally competitive commercial products if we lose sight of our end users and their entire interaction with the product life cycle Be Unconstrained by Convention - Our only limits are the laws of physics. Many, even experts, will say what we are working on is impossible. They said the same about SpaceX reusing rockets. Generationally impactful companies, by definition, must accomplish the seemingly impossible. If it were easy, it would have already been done. Never shy away from a solution because it has never been tried before, and never choose to do something because that’s "how it's always been done" Go Where the Work Is - Never miss a chance to meet a customer, user, or stakeholder face to face, even if that means hopping on a plane. If you can’t make it, find a teammate who can channel your intentions and go in your place. Deep work can be done from anywhere, but we believe teams are built in person, and aim to maximize our time together Operate in the Grey - Embrace nuance in pursuit of truth. Question every fundamental assumption Equal Opportunity Antares is an Equal Opportunity Employer. Employment decisions are based solely on merit, competence, and qualifications, without regard to race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status. ITAR Requirements To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State. Learn more about the ITAR here. #J-18808-Ljbffr Antares