Founding Thermal Engineer

Zephyr Fusion; Vista (CA); On-site; USD 120,000 - 170,000; Full time

Job summary

Zephyr Fusion is seeking a driven thermal engineer to own the full lifecycle of spacecraft thermal systems, from architecture through integration and testing. Based on the Vista, CA site, you will develop and validate thermal models, lead trade studies, and collaborate with multidisciplinary teams to meet demanding space-power requirements.

The role emphasizes hands-on R&D, experience with active and passive thermal control, and familiarity with TVac testing and common thermal software such as

Qualifications

• Expertise in thermal analysis and design for complex systems.
• 8+ years of relevant experience in fast-moving teams.
• Independent work style with minimal oversight.
• Experience with TVac testing and thermal modeling software.

Responsibilities

• Own the thermal system architecture and analysis for space applications.
• Conduct thermal design trade studies balancing performance, resources, risk and schedule.
• Develop and maintain integrated thermal models for Zephyr Fusion.
• Design and execute thermal tests for high-performance aerospace systems.
• Collaborate with other spacecraft disciplines to define thermal requirements.

Skills

Thermal Analysis

Thermal System Design

Independent Work

Thermal Modeling Tools

Tools

COMSOL

ANSYS

Job description

Zephyr Fusion (YC F25) is pioneering the development of compact megawatt-class fusion reactors designed specifically for space. By leveraging high-temperature superconducting (HTS) magnets and decreasing space launch costs, Zephyr Fusion harnesses the unique advantages of the space environment to create novel solutions for high-power applications. Zephyr Fusion aims to enable the industrialization of the space economy by building spacecraft power systems with orders of magnitude higher power densities vs. conventional satellite power systems.

Role Description

We are seeking a driven and innovative thermal engineer to own the full lifecycle of cutting‑edge thermal systems, from architecture through to integration and launch. This role is a unique opportunity to lay the foundations of the thermal engineering team here at Zephyr Fusion with a focus on designing and developing novel thermal systems for advanced space applications. You will play a pivotal role in bringing Zephyr Fusion's groundbreaking space technologies to life and collaborating with a multidisciplinary team to meet innovative engineering goals.

This is a full-time, on‑site role located in Vista, CA

Due to ITAR and export control restrictions candidates must be US persons.

Responsibilities Include

• You will own the success of the thermal system architecture and thermal analysis that will be key to our operations in space
• Own thermal design trade studies that successfully balance performance margins, resource use, risk, cost, and schedule
• Develop and maintain integrated thermal analysis models for Zephyr Fusion
• Design and execute thermal tests for complex high-performance aerospace systems
• Work collaboratively with other spacecraft disciplines to define thermal hardware requirements, such as optical properties, conductances, insulation, passive, and or active thermal control
• Interface with stakeholders as a technical authority in the physics of heat transfer
• Establish effective processes and standards for thermal engineering at Zephyr Fusion

Qualifications

• Expertise in Thermal Analysis and Thermal System Design with the ability to model and simulate heat flow in complex systems
• 8 or more years of relevant experience. We highly value time spent in fast-moving, execution-focused teams and product-driven cultures
• Demonstrated ability to work independently with minimal technical oversight
• Thorough understanding and experience in both active and passive thermal control systems
• Experience in planning and executing Thermal Vacuum Chamber (TVac) testing.
• Proficiency with thermal modeling software and tools (e.g., COMSOL, ANSYS, or similar)
• Problem-solving skills, attention to detail, and ability to work collaboratively in a hands-on R&D environment

Preferred

• Experience with Thermal Management and Thermal System Design for high-performance applications
• Experience with the design, analysis, manufacturing, testing, and operation of spacecraft thermal control systems for all relevant modes of heat transfer, both active and passive, and through all phases of program lifecycle
• Experience working with multi-layer insulation: design, fabrication, installation, and test
• Familiarity with typical spacecraft thermal control technologies (e.g. heat pipes, pumped fluid systems, thermal blankets, optical coatings, etc.)
• Experience leading integrated-team thermal engineering efforts: innovation projects, concurrent engineering, digital engineering, vehicle-level thermal design, hosted or multiple-payload missions, anomaly and root-cause investigation