Thermal Engineer (Senior)

The role

The Senior Thermal Engineer will own the thermal design and performance of spacecraft from concept through flight. This role involves developing thermal models, designing thermal control solutions, and working with flight hardware through integration, test, and launch.

What you will do

• Lead payload thermal design, analysis, and integration from concept through on-orbit operations.
• Own the thermal technical interface with external customers.
• Develop and maintain spacecraft- and payload-level thermal models using Ansys Thermal Desktop.
• Develop and implement advanced passive thermal control solutions.
• Design and analyze active thermal-fluid systems.
• Collaborate with mechanical, systems, avionics, and GNC engineering disciplines.
• Plan and execute thermal subsystem milestones and technical reviews.
• Support thermal hardware development, integration, build, and test.
• Correlate test and flight data to thermal models.

Required qualifications

• U.S. Person status is required
• Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, or a related field
• 5+ years of experience in thermal engineering or analysis
• Experience with thermal modeling and analysis tools
• Strong understanding of heat transfer and thermal engineering fundamentals
• Strong analytical and problem-solving skills

Nice to have

• Experience with spacecraft or aerospace thermal systems
• Proficiency with Ansys Thermal Desktop
• Experience designing spacecraft thermal control systems
• Experience with thermal vacuum testing, instrumentation, and data acquisition
• Experience correlating thermal models with test or flight data
• Familiarity with spacecraft thermal margin standards and requirements
• Working knowledge of two-phase thermal control systems
• Experience with Siemens NX and Teamcenter

Benefits

• Equity in Apex
• 100% company-paid medical, dental, and vision for you and dependents
• $100k life insurance at no cost
• 15 to 20+ days vacation annually
• 10 paid holidays
• 401(k) with 100% match on first 3% and 50% on next 2%
• 8 weeks paid parental leave
• Childcare reimbursement up to $350/day for work-related travel
• Daily catered lunch and unlimited snacks
• Monthly office socials, pickleball tournaments, run club, and gatherings
• Dream desk setup

Before you apply

• U.S. Person status is required to access export-controlled data
• Must qualify as a U.S. Person or be able to obtain required export authorizations

About the company

Apex manufactures satellite buses at scale using software, vertical integration, and hardware designed for manufacturing. The company is a fast-growing startup that has raised more than $500M in funding.