Vast is seeking a Senior Thermal Engineer to define the thermal architecture and own thermal analysis for a new constellation-ready 15kW spacecraft bus — a product line designed to scale to hundreds of spacecraft per year. 

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

About this role:

We're designing a high-power satellite bus that accommodates multiple payload types — including a compute-intensive Nvidia payload with significant thermal dissipation. The thermal architecture is a first-order design decision for this bus, not an afterthought. You'll own thermal analysis and design from system architecture through flight delivery, starting during the architecture trade studies.

The thermal challenges span the full range: multiple payload configurations with different thermal profiles, high-power-density electronics with demanding heat rejection requirements, and a production-rate design that must be repeatable across hundreds of spacecraft. You'll start as the sole thermal engineer and build a team as the program scales.

Responsibilities: 

• Define the thermal control architecture — trade passive, heat pipe, and pumped fluid loop approaches, radiator sizing and placement
• Perform system-level and component-level thermal analysis for the satellite bus across all payload configurations
• Address the high-power thermal challenge — Nvidia compute module drives heat rejection requirements that may force the architecture
• Contribute first-order thermal models to the spacecraft design, simulation, and digital twin tool for fast design iteration, then validate using traditional analysis tools (e.g., Thermal Desktop)
• Develop and maintain the detailed system thermal model
• Own the thermal budget — min/max temperatures per component vs qualification limits, across all orbital conditions
• Select thermal coatings and materials (AZ-93, S13G, Kapton, Aeroglaze, etc.)
• Specify and procure emissivity control materials and RTDs (temperature sensors)
• Plan TVAC test campaigns — define chamber requirements, test profiles, success criteria (feeds facility planning)
• Correlate thermal models to test data after environmental testing
• Support solar array thermal analysis (coordinate with solar array team lead)
• Support box-level thermal design for new clean-sheet avionics designs — power dissipation, interface temperatures, mounting thermal resistance

Minimum Qualifications:

• Bachelor's degree in Mechanical Engineering, Aerospace Engineering, or a related technical discipline
• 6+ years of spacecraft or aerospace thermal engineering experience
• Spacecraft thermal control design and analysis experience — passive and active systems
• Built and correlated thermal models for flight hardware
• Experience with high-power / high-dissipation thermal challenges
• Familiar with thermal coatings, MLI, radiators, heat pipes, thermal straps
• TVAC test planning and execution experience
• Comfortable working during early architecture phases — you can make thermal architecture recommendations with incomplete data and refine as the design matures
• Experience across multiple thermal analysis tools (Thermal Desktop, SINDA, ESATAN, or equivalent)

Preferred Skills & Experience:

• Able to obtain a security clearance
• Experience with multi-satellite builds where thermal design must be consistent across units
• High-power-density thermal design experience
• Thermal design for payloads with variable duty cycles
• Cryogenic or specialized thermal control experience