Senior Space Thermal Engineer (Nuclear Systems)

Location: Torrance, California, United States; onsite work at a dedicated facility

Salary: $145,000–$185,000 per year, plus stock options

Company

hirify.global is a Series C startup developing mass-producible, inherently safe nuclear microreactors for terrestrial, underwater, and space applications.

What you will do

• Own and validate thermal models for reactor cores, spacecraft, radiator systems, and integrated vehicle thermal response.
• Develop thermal management architectures for reactor heat transport, coolant loops, radiators, and integrated heat rejection systems.
• Use modeling and first-principles analysis to guide architecture decisions, system integration, hardware design trades, and operating-limit assessments.
• Anchor models to experimental, analytical, and test data; quantify uncertainty and improve model fidelity.
• Define and interpret thermal, coolant-loop, radiator, heat-pipe, and high-temperature heat-transfer tests with test engineering teams.
• Document analyses, model validation, design trades, interface requirements, test plans, risks, margins, and verification approaches.

Requirements

• Bachelor’s degree in mechanical, aerospace, nuclear engineering, thermal sciences, or a related technical discipline.
• 5+ years of experience in thermal engineering, thermal analysis, heat transfer, spacecraft thermal systems, nuclear systems, high-temperature systems, or related hardware development.
• Strong fundamentals in conduction, convection, radiation, transient heat transfer, thermal-fluid systems, and system-level thermal modeling.
• Experience building and validating thermal models using test, experimental, flight, or hardware data.
• Experience performing thermal design trades and communicating assumptions, uncertainty, margins, and design implications to cross-functional engineering teams.
• Applicants must be U.S. citizens or nationals, lawful permanent residents, refugees, asylees, or eligible to obtain the required U.S. government authorizations under export regulations.

Nice to have

• Master’s degree or higher in a relevant engineering or thermal sciences field.
• Experience with spacecraft thermal control systems, radiators, heat pipes, thermal straps, louvers, MLI, coatings, or orbital thermal analysis.
• Experience with high-temperature or nuclear thermal systems, reactor heat transport, pumped loops, liquid-metal or gas coolants, and refractory materials.
• Experience with Python, Git, Thermal Desktop, SINDA/FLUINT, OpenTD, ANSYS, COMSOL, STAR-CCM+, or Fluent.
• Experience with reduced-order models, parametric trade tools, thermal vacuum testing, coolant-loop testing, or thermal hardware integration.

Culture & Benefits

• Work on advanced nuclear energy systems for defense, climate, and space applications.
• Collaborate across reactor, fluids, mechanical, materials, test, and systems engineering disciplines.
• Work in a new 322,000-square-foot facility supporting collaboration, R&D, and production.
• Company values systems thinking, user focus, unconventional solutions, nuanced decision-making, and in-person collaboration.
• Compensation includes a significant stock option package in addition to salary.