Senior Mission Engineer

About Us At 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 key member of the Mission Engineering team, you will lead programs across commercial, defense, and space microreactor missions – both on Earth and in space. You will serve as a primary technical point of contact for customers and stakeholders, driving the development, deployment, and application of Antares systems to meet mission needs. You will operate at the intersection of engineering, product development, customer program execution, and mission integration, owning how the complete product is applied to real-world missions from concept through end of life. You'll have strong engineering and physics fundamentals – particularly in thermodynamics, heat transfer, fluid mechanics, energy and power systems, and engineering economics – with demonstrated ability to reason from first principles, develop quantitative models, and maintain high technical rigor across disciplines. You will own product integration into operational end-user environments. The ideal candidate is a technically rigorous generalist comfortable moving between engineering disciplines, hands-on analysis, hardware, program execution, and customer-facing work. They can rapidly develop depth in unfamiliar areas, communicate effectively across engineering teams, and drive ambiguous problems to closure. Experience with DoD, DOE, NASA, or other government sponsors and procurement processes is preferred.   Roles & Responsibilities - Lead execution of customer-facing and customer-funded R&D programs, owning cost, schedule, quality, contractual compliance, milestone execution, technical deliverables and internal/external reviews to align stakeholders and ensure mission success. - Manage program costs, schedules, quality, and deliverables; translating customer needs into technical requirements; and performing or coordinating the engineering needed to close cross-disciplinary gaps. - Drive product development to ensure Antares systems can be transported, deployed, commissioned, operated, integrated with customer infrastructure, maintained, and decommissioned. - Success in this role requires a generalist mindset, cross-disciplinary problem-solving, and relentless focus on delivering value to our customers. - Own mission-level product integration across the R1 lifecycle, translating customer needs into requirements, interfaces, operational concepts, and product development priorities that ensure the complete system can accomplish its intended mission. - Perform first-principles analyses across disciplines, developing models and tools as needed to evaluate trade spaces, quantify mission impacts, answer mission-level questions, and close technical gaps between subsystem teams. - Ideate and develop new applications and customer missions for Antares technology, supporting RFIs, proposals, white papers, and contract capture with technical concepts, system performance justifications, development roadmaps, and customer use cases. - Lead and contribute to system architecture, interface definition, and technical trade studies, integrating engineering, operational, cost, schedule, and business considerations into product and program decisions. Basic Qualifications: - Bachelor's degree in an engineering discipline (mechanical, electrical, aerospace, nuclear, systems, etc.), physics, or applied science. - Exceptional technical writing and communication skills, with demonstrated ability to synthesize multidisciplinary engineering work into clear customer-facing deliverables. - 5+ years of experience developing or delivering technically complex systems in aerospace, nuclear, energy, automotive, defense, or another mission- or safety-critical environment, with demonstrated ownership of multidisciplinary technical problems and program cost/schedule/technical performance. Preferred Skills and Experience: - Master’s degree or PhD in an engineering field. - Proficiency in Python for numerical/multiphysics work and familiarity with modern toolchains (Git and CI/CD). - Strong foundations in thermodynamics, heat transfer, fluid mechanics, energy conversion and power systems, and engineering economics. - Experience developing, integrating, testing, or commissioning complex hardware or energy systems. - Experience with mission engineering, CONOPS development, system architecture, modeling and simulation, and trade studies. - Experience across one or more adjacent technical domains such as high-temperature systems, turbomachinery, materials and composites, power systems, nuclear, or aerospace. - Experience with government sponsors (DoD, DOE, NASA, USAF/USSF) and government-funded R&D, proposals, or contracting. - Strong interpersonal and collaborative skills, enthusiasm for problem-solving, and a desire to optimize modern nuclear design and operation. - Ability to drive decisions and close ambiguous cross-functional problems despite incomplete information and conflicting constraints. - Experience working in a start-up environment. Additional Requirements - Ability to travel to customer and mission-relevant locations as needed. - Ability to obtain a Top Secret or Top Secret SCI clearance is preferred. Salary Range - Senior Mission Engineer - $145,000 - $185,000 Location - We are located in Torrance, CA in a 322,000 square foot, brand new facility featuring large open spaces for team collaboration, R&D, and production, as well as easy access to the 405, 105, and 110 freeways. Our facility is in the heart of Los Angeles' vibrant emerging tech ecosystem alongside many other high growth startups and enterprises. Culture At Antares, we like to specifically tie each role to our founding document’s set of values–here are the top five cultural values we think you should believe at your core to be successful: - 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 https://www.pmddtc.state.gov/?id=ddtc_kb_article_page&sys_id=24d528fddbfc930044f9ff621f961987.