Thermal Engineer (Mid)

The role

You will design, analyze, and optimize spacecraft thermal systems. You will work cross-functionally to develop thermal solutions for avionics, electro-mechanical systems, and spacecraft structures.

What you will do

• Develop and maintain spacecraft-level thermal models using Ansys Thermal Desktop and other analytical tools.
• Collaborate with subsystem engineers to design and optimize thermal control systems for avionics and electro-mechanical components.
• Evaluate the validity of thermal analysis results and ensure compliance with Mil-Standard, Aerospace TOR, and vendor requirements.
• Plan, execute, and manage thermal testing campaigns, including thermal vacuum (TVAC) and thermal cycling tests.
• Work with mechanical teams to develop passive and active thermal management hardware, including radiators, heaters, heat pipes, and coatings.
• Support thermal subsystem milestone reviews (SRR, PDR, CDR, MRR).
• Perform thermal model correlation using flight and test data.
• Oversee thermal flight hardware integration and quality control.
• Utilize Siemens NX and Teamcenter for thermal design and integration.

Required qualifications

• 3+ years of experience in radiative and conductive thermal modeling of spacecraft systems using Thermal Desktop or similar software.
• Strong understanding of thermal margin definitions and aerospace thermal control standards.
• Experience selecting, sizing, and designing thermal control hardware, including heat pipes, heaters, OSR, SSM, MLI, TEC, thermal paints, and tapes.
• 1+ year of experience with thermal cycling and thermal vacuum testing, including setup, instrumentation, and model correlation.

Nice to have

• Experience with full-vehicle thermal vacuum testing and thermal model correlation.
• Familiarity with 2-phase spacecraft thermal control systems.
• Knowledge of PCBA thermal modeling and thermal interface materials (thermal grease, gap pads, etc.).
• Experience with integrated spacecraft and launch vehicle thermal analysis.
• Proficiency in Python, C/C++, or Matlab for thermal modeling and automation.
• Understanding of SMC-S016 standards or equivalent.
• Familiarity with Atlassian software tools and engineering workflows

Benefits

• Equity in Apex
• 100% company-paid medical, dental, and vision for you and your dependents
• $100k life insurance at no cost
• Starting at 15 days vacation, growing to 20+ days annually
• 10 paid holidays
• 100% match on first 3% and 50% on next 2% 401(k) matching
• 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

• Must qualify as a U.S. Person (U.S. citizen or national, lawful permanent resident, refugee, or individual granted asylum) 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. They are a fast-growing startup that has raised more than $500M in funding.