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. Formed in 2023, the Antares team hails from SpaceX, The White House, MIT, Rigetti Computing, The Air Force, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Los Alamos, Idaho, and Oak Ridge. Antares has raised over $600M in venture capital from top-tier investors and has over $13M in government funding. About the Role Antares is seeking a Senior Firmware Engineer to build the embedded software that enables our first-of-a-kind microreactor hardware to operate reliably in real time. This firmware sits at the interface between custom electronics and reactor control infrastructure, translating sensor signals, device commands, timing requirements, diagnostics, and fault responses into dependable behavior at the hardware level. In this role, you will develop firmware for embedded controllers, instrumentation electronics, data acquisition systems, and test hardware. You will help define how reactor hardware is initialized, monitored, commanded, diagnosed, and protected across development, integration, and qualification environments. You will work closely with electrical, controls, reactor software, safety, and test teams to design, implement, bring up, and validate firmware that interacts directly with sensors, actuators, custom electronics, communication buses, control algorithms, and hardware-in-the-loop systems. Your work will be central to ensuring Antares’ reactor hardware can be safely operated, tested, diagnosed, qualified, and eventually deployed. Key Responsibilities * Design, develop, test, and maintain firmware for reactor instrumentation, control, monitoring, and electrical support systems. * Develop embedded software in C/C++ for microcontrollers, embedded processors, and real-time hardware platforms. * Bring up new hardware, debug board-level issues, and validate firmware behavior using oscilloscopes, logic analyzers, multimeters, power supplies, and other lab equipment. * Implement communication interfaces such as SPI, I2C, UART, CAN, Ethernet, RS-485, or similar protocols. * Develop firmware for sensor acquisition, actuator control, telemetry, diagnostics, fault detection, and system health monitoring. * Collaborate with electrical engineers on schematics, board design reviews, signal integrity concerns, interface definitions, and hardware/software requirements. * Collaborate with systems, software, test, and licensing teams to ensure firmware supports safety, reliability, and regulatory requirements. * Participate in design reviews and ensure firmware designs are technically sound, testable, and traceable. * Support hardware-in-the-loop and hardware-in-the-loop testing, automated test frameworks, data acquisition systems, and integration campaigns. * Develop firmware test plans, verification procedures, and documentation for configuration-controlled hardware and software releases. * Analyze failure modes, define safe states, and implement fault-handling logic for embedded systems. * Drive root-cause investigations for firmware, electrical, and integration issues through bench testing and system-level debugging. Basic Qualifications * Bachelor’s degree in Computer Science, Computer Engineering, Software Engineering, or a related technical field. * Five years or more of experience developing production software in C, C++, Python, Rust, or similar languages for hardware-integrated, distributed, embedded, robotics, aerospace, automotive, industrial, or mission-critical systems. * Experience building multi-threaded or multi-process software systems, including IPC, networking, message passing, or publish/subscribe architectures. * Experience integrating software with sensors, controllers, DAQs, power supplies, embedded systems, or other hardware-facing interfaces. * Strong debugging skills across software, hardware, and system-integration boundaries. * Ability to design clear software interfaces, data models, state machines, and testable system behaviors. * Comfortable working in an environment where requirements evolve through prototype testing, hardware bring-up, and cross-functional design tradeoffs. * Strong written and verbal communication skills, especially when working across software, electrical, controls, test, and systems engineering teams. Preferred Skills & Experience * Experience working in regulated or safety-critical environments such as nuclear, aerospace, defense, automotive, maritime, medical devices, industrial controls, or robotics. * Experience with real-time systems, RTOS-based development, bare-metal firmware, or safety-critical embedded software. * Experience with hardware bring-up, board-level debugging, root-cause analysis, and firmware validation. * Experience developing firmware for sensors, actuators, power electronics, control systems, data acquisition, or telemetry systems. * Exposure to Hardware in the Loop testing, automated test frameworks, simulation environments, or continuous integration for embedded systems. * Familiarity with bootloaders, firmware update mechanisms, device drivers, low-level peripherals, and embedded communication stacks. * Familiarity with software or firmware development processes for configuration-controlled systems. * Familiarity with relevant standards, guidance, or development practices in safety-critical systems, including IEEE, IEC, DO-178C, DO-254, IEC 61508, ISO 26262, DOE nuclear standards, or similar. * Experience contributing to formal design reviews, hazard analyses, verification plans, or qualification documentation. * Demonstrated ability to take ownership of ambiguous embedded systems problems and drive them to closure. 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.