Senior Thermal Engineer, Lunar

Vast is seeking a Senior Thermal Engineer, Lunar, reporting to the SVP, Lunar Programs, to own thermal architecture and analysis for Vast's lunar surface elements — a surface power station and a crewed habitat, airlock, and node designed to survive and operate through the full lunar diurnal cycle.

As one of the founding engineers on the Lunar team, you'll play an essential role in developing Vast's lunar ecosystem. In this role you will serve as the lead for thermal control of hardware destined for the lunar surface - defining, analyzing, and qualifying the radiators, fluid loops, heat pipes, MLI, coatings, and survival heating architecture that will keep crewed and non-crewed lunar systems alive. You will own the thermal architecture end-to-end, from first-order trades through model correlation and flight, and help establish the thermal design standards, margin policy, and environment definitions that Vast's lunar hardware will be built on.

This will be a full-time, exempt position located in our Long Beach location.

Responsibilities:

• Define the thermal control architecture for Vast's lunar surface elements - trading passive, heat pipe, pumped fluid loop, and thermal storage approaches against mass, power, complexity, and dust exposure
• Size and place radiators for the lunar surface environment, accounting for diurnal sink temperature swings, albedo and lunar IR loading, terrain and self-view blockage, and latitude-driven constraints
• Own the survival thermal case through lunar night - heater power budget, thermal mass and phase-change storage strategy, and dormancy and wake-up thermal states
• Own the habitat, airlock, and node thermal control - cabin temperature and humidity control, condensing heat exchanger, coolant loop architecture, and depress/repress thermal transients
• Build and maintain the detailed system thermal models, contribute reduced-order models to Vast's design, simulation, and validate against Thermal Desktop, SINDA/FLUINT, or equivalent
• Own the thermal budget: min/max predicted temperatures per component against qualification limits across launch, cruise, descent, landed day, landed night, and off-nominal conditions
• Select thermal coatings, MLI, heat pipes, thermal straps, isolators, heaters, and RTDs for the lunar environment, with explicit accounting for regolith dust deposition, abrasion, and UV degradation of end-of-life optical properties
• Plan and execute TVAC and thermal balance test campaigns (chamber and shroud requirements, solar and IR simulation, cold-case survival demonstration, test profiles and success criteria), then correlate models to test data
• Establish the thermal design standards, margin policy, and lunar environment definitions Vast's lunar hardware will be built on, and support design reviews, drawing checks, and NASA technical deliverables

Minimum Qualifications:

• Bachelor's degree in Mechanical Engineering, Aerospace Engineering, Physics or a related technical discipline
• 6+ years of spacecraft or aerospace thermal engineering experience
• Spacecraft thermal control design and analysis experience
• Built and correlated thermal models for flight hardware
• Experience with extreme-environment or wide-swing thermal design where both hot and cold cases were design-driving
• Familiar with thermal coatings, MLI, radiators, heat pipes, thermal straps, and heater/thermostat design
• Comfortable working during early architecture phases
• Experience across multiple thermal analysis tools (Thermal Desktop, SINDA/FLUINT, ESATAN, or equivalent)

Preferred Skills & Experience:

• TVAC and thermal balance test planning and execution experience, preferred
• Lunar or planetary surface thermal experience, including diurnal survival design (thermal switches) and regolith conduction modeling
• Crewed vehicle thermal experience: cabin ATCS, condensing heat exchangers, humidity control, ECLSS thermal interfaces, or touch temperature compliance for human-rated hardware
• Airlock, EVA systems, or suit thermal experience, including depress/repress thermal transients
• Pumped fluid loop design - working fluid selection, pump and accumulator sizing, freeze protection, and loop control
• Familiarity with lunar dust effects on thermo-optical properties and dust mitigation strategies

Additional Requirements:

• Willingness to work evenings and/or weekends to support critical mission milestones
• Ability to travel up to 5% of the time to support customer meetings