Senior Thermal Engineer - Space

The role

You will own and drive the thermal design and analysis of a space nuclear vehicle. This includes the reactor, spacecraft, and heat rejection systems.

What you will do

• Construct, own, and validate thermal models for the reactor core, spacecraft, radiator systems, and integrated vehicle thermal response.
• Anchor thermal models to experimental, analytical, and test data.
• Identify gaps in thermal, materials, coolant-loop, radiator, and reactor heat-transfer data.
• Develop and analyze space nuclear thermal management architectures.
• Generate, compare, and downselect heat rejection system configurations.
• Build system-level thermal models to assess vehicle-level performance.
• Create tools, methods, and analysis processes for predicting radiator thermalization behavior.
• Investigate and develop thermal hardware integration approaches.
• Support early-stage concept development through modeling-driven design trades.
• Partner with reactor, mechanical, fluids, materials, test, and systems teams.

Required qualifications

• Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, 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 closely 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 data, experimental data, or flight/hardware data.
• Experience performing thermal design trades and communicating model assumptions, uncertainty, margins, and design implications to cross-functional engineering teams.

Nice to have

• Master’s degree or higher in Mechanical Engineering, Aerospace Engineering, Nuclear Engineering, Thermal Sciences, or a related field.
• Experience with spacecraft thermal control systems, radiators, heat pipes, thermal straps, louvers, MLI, coatings, spacecraft environmental interfaces, or orbital thermal analysis.
• Experience with high-temperature thermal systems, nuclear thermal systems, reactor heat transport, Brayton/Rankine/Stirling-adjacent thermal architectures, pumped loops, liquid metal coolants, gas coo
• Experience developing or analyzing heat rejection systems for space, nuclear, defense, aerospace, or high-reliability energy systems.
• Strong familiarity with Python and Git-controlled code repositories.
• Familiarity with thermal modeling and simulation tools such as Thermal Desktop, SINDA/FLUINT, OpenTD, ANSYS, COMSOL, STAR-CCM+, or Fluent.
• Experience developing reduced-order models, sizing tools, parametric trade tools, or integrated system models for thermal architecture studies.
• Experience designing, executing, or interpreting thermal vacuum, component-level, coolant-loop, heat pipe, radiator, or high-temperature heat-transfer tests.
• Understanding of radiator performance drivers, including view factors, emissivity, absorptivity, fin efficiency, thermal spreading, panel thermalization, degradation, and environmental effects.
• Experience with coolant loop architecture, pump/valve/heat exchanger integration, pressure drop, flow stability, startup/shutdown transients, or two-phase/single-phase thermal-fluid systems.

About the company

Antares is building mass-producible, inherently safe, deployable microreactors that can be used terrestrially, underwater, and in space. Their mission is to make clean energy abundant from Earth to the Asteroid Belt.