Antares

Mechanical Design Engineer II - Reactivity Controls

Los Angeles
Full-time
$115K - $185K
Posted Aug 27, 2026

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Skills

Hydraulics
Leadership
Robotics
Teamwork
Finite Element Analysis
MATLAB
Python

Job description

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 the Responsible Engineer for Reactivity Controls – Mechanical, you will lead

the design, development, testing, and validation of the mechanical systems that

govern reactor reactivity and ensure the safe operation of the reactor. You will

architect and build the mechanical mechanisms that interface with electrical and

software subsystems, collaborating closely across disciplines to define system

architecture, requirements, and documentation.

The ideal candidate has a strong track record in designing and developing

precision control mechanisms, preferably with experience in robotics or

electromechanical systems. You will also contribute to system-level architecture

trade studies and support the evaluation and selection of key vendors.

Roles and Responsibilities:

•Design, build, and test the reactor’s control mechanisms, hardware and

assemblies.

•Concept and develop custom actuation solutions, including mechanisms,

linkages, interfaces, and instrumentation.

•Define design criteria, requirements, system architecture, and

verification/validation test plans.

•Collaborate closely with cross-functional teams across thermal, structural,

neutronics, controls, and simulation disciplines.

•Engineer components for high-temperature, high-stress, and radiation

environments using metals, ceramics, and other advanced materials.

•Perform design-for-manufacturability (DFM) assessments and execute

tradeoffs across performance, cost, schedule, and risk.

•Conduct mechanism trade studies, document findings, and present

recommendations to senior leadership

Basic Qualifications:

•Bachelor's degree in engineering

•3+ years of experience in a full-cycle design engineering roles,

encompassing hands-on experience with CAD, analysis, build and test

•Experience with kinematic synthesis, pneumatic/hydraulic actuation,

mechatronics and instrumentation

•Experience with FMEA including structure strength, stability and fatigue

failure modes

Preferred Skills & Experience:

•Master's degree in engineering

•1+ years of experience in a full-cycle design engineering roles,

encompassing hands-on experience with CAD, analysis, build and test

•Experience in the Nuclear, Aerospace, or Robotics industries

•Experience in a demanding fast-paced development environment

•Experience with design engineering tools such as NX, ANSYS or Femap, and

other product lifecycle software

•Experience with engineering scripting languages such as Python and

MATLAB

Additional Requirements:

•Ability to work long hours and weekends as necessary to support critical milestones

Location

•We are located in Torrance, CA in a 145,000 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.

Salary Range

•Mechanical Design Engineer II - $115,000 - $150,000

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.