Thermo-Mechanical Engineer II

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. 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. We’ve raised over $600M in venture capital and have contracts worth hundreds of millions with the military, NASA, and the Department of Energy.

About the role

As the Thermal-Mechanical Engineer for Integration of the Power Conversion System (PCS), you will own how heat moves through the system, including the thermal budget and its impact on hardware over time. Your scope spans from the thermal energy budget of the whole system down to the insulation on a single hot-section joint. You will develop the heat rejection and cold-sink architecture, size and integrate the recuperator, define the thermal configuration of the hot section (insulation, heat-loss budget, surface temperatures, and personnel protection), and manage thermal interfaces and transient requirements against major PCS components, the reactor, and safety systems.

You are responsible for temperature-related life-limited hardware, including mitigations, inspection procedures, and a maintenance plan. You will participate in testing, drive instrumentation placement, correlate models against real-world data, and refine designs based on findings. The ideal candidate is fluent in heat transfer across conduction, convection, and radiation, has sized real thermal hardware, and is comfortable owning the heat-loss budget and cold-sink margin while collaborating with component owners to meet thermal performance goals. Experience with high-temperature power cycles, creep, thermal-mechanical fatigue, or first-of-a-kind hardware commissioning is a strong differentiator.

Responsibilities

• Own thermal management and thermal energy budget of the Power Conversion System, closing the loop with cycle performance on parasitic losses.
• Develop the heat rejection and cold-sink architecture, sizing and integrating the recuperator and heat rejection against site and ambient conditions.
• Define the thermal configuration, including insulation selection and design, heat-loss budget, surface temperatures, instrumentation, and personnel protection.
• Manage thermal interfaces and transient requirements for major PCS components, reactor, and safety systems.
• Support test rig design and instrumentation placement, using collected data to improve component life and performance.
• Engineer components for high-temperature and high-stress service using metals and advanced materials, in partnership with materials and structural analysis teams.
• Develop inspection and maintenance plans for thermal-mechanically life-limited hardware.
• Collaborate with Mechanical, Electrical, Safety, and Nuclear teams to ensure designs meet overall objectives and requirements.

Requirements

• Bachelor's degree in Mechanical, Aerospace, Nuclear, or a related engineering discipline.
• 2+ years of full-cycle engineering experience for Engineer II.
• Experience performing thermal analysis (hand calculations and FEA or CFD) to size, configure, or qualify hardware.
• Experience designing thermal management hardware for high-temperature systems, such as insulation systems, heat-loss budgets, or thermal isolation.
• Experience sizing or integrating heat exchangers or a heat rejection path against real operating and ambient conditions.
• Experience correlating thermal predictions against test data and revising designs based on results.
• Experience owning thermal interfaces or requirements across multiple subsystems.
• Ability to work long hours and weekends as necessary to support critical milestones.

Skills

• Experience in the Nuclear, Aerospace, Automotive, Power Generation, Motorsports, or Oil and Gas industries.
• Experience with recuperators, air-cooled or dry heat rejection, and ambient-dependent performance derating.
• Experience selecting and designing high-temperature insulation systems, including hot-face and cold-face design and personnel-protection surface temperature limits.
• Experience with transient thermal analysis of startup, shutdown, trip, and off-nominal cases.
• Experience with thermal-mechanical fatigue, creep, and creep-fatigue interaction, and life assessment of temperature-limited components.
• Experience with elevated-temperature design codes such as ASME BPVC Section III Division 5 or Section VIII Division 2 Part 5.
• Experience with high-temperature metals and advanced materials, including nickel superalloys and their creep-limited allowables.
• Experience specifying thermal instrumentation (thermocouple and RTD selection, placement, and measurement uncertainty) and using it to correlate models.
• Experience developing inspection and maintenance plans for life-limited hardware, including NDE method selection.
• Experience with thermal and structural analysis tools such as ANSYS Mechanical, Femap or NX Thermal, and/or CFD tools such as Fluent or Star-CCM+.
• Experience commissioning first-of-a-kind hardware and supporting thermal startup and troubleshooting.
• Experience in a demanding, fast-paced development environment.

Benefits

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, with easy access.

Pay

Thermo-Mechanical Engineer II: $115,000 - $150,000

Culture

At Antares, we tie each role to our founding document’s set of values. Here are the top five cultural values we believe you should embody to be successful:

• Think in Systems – Energy and Defense are complex ecosystems. First principles thinking alone is insufficient. Think probabilistically and take action. “If you want to be certain, then you are apt to be obsolete.” Over-optimizing 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 will say what we’re working on is impossible. Generationally impactful companies must accomplish the seemingly impossible.
• Go Where the Work Is – Never miss a chance to meet a customer, user, or stakeholder face-to-face. Deep work can be done anywhere, but teams are built in person.
• Operate in the Grey – Embrace nuance in pursuit of truth. Question every fundamental assumption.

Antares is an Equal Opportunity Employer. Employment decisions are based solely on merit, competence, and qualifications. ITAR requirements apply: Applicants must be U.S. citizens, lawful permanent residents, refugees, or asylees, or eligible for required authorizations.