Thermal Engineer (Mid)

Spacecraft represent the most pressing unmet need across the entire aerospace industry. As more launch vehicles come online and the cost to orbit decreases, more companies launching payloads to space continue to emerge. For the first time in history, this influx of payload companies combined with reduced launch costs has resulted in a massive increase in need for commercial spacecraft platforms, known as satellite buses. These buses hold the payloads of our customers and are flown on launch vehicles. Apex manufactures these satellite buses at scale using a combination of software, vertical integration, and hardware that is designed for manufacturing. Our spacecraft enable the future of society: ranging from earth observation to communications and more. We’d love for you to join us on our mission of providing humankind access to the galaxy beyond our planet. About The Role We are seeking a Thermal Engineer to play a key role in designing, analyzing, and optimizing spacecraft thermal systems. You will work cross-functionally to develop thermal solutions for avionics, electro‑mechanical systems, and spacecraft structures while focusing on reducing the cost and complexity of traditional satellite thermal subsystems. This position requires expertise in thermal modeling, testing, and hardware integration to ensure mission success. Responsibilities 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. Requirements 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. Preferred Qualifications 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. Why Join Apex? Apex believes in creating a work environment that you look forward to embracing every day. Our employees love working at Apex, and we want you to love it too. We're a fast‑growing startup backed by $200M in Series D funding, and we invest heavily in our people from day one. What We Offer For Full‑time Employees Shared upside: Receive equity in Apex, letting you benefit from the work you create Best‑in‑class healthcare: 100% company‑paid medical, dental, and vision for you and your dependents, plus $100k life insurance at no cost Comprehensive PTO package to reset and recharge - starting at 15 days vacation, growing to 20+ days annually, plus 10 paid holidays Competitive 401(k) plan with generous matching - 100% match on first 3%, 50% on next 2% 8 weeks paid parental leave plus childcare reimbursement up to $350/day for work‑related travel Daily catered lunch and unlimited snacks to keep you fueled throughout the day Vibrant community: Monthly office socials, pickleball tournaments, run club, and gatherings for you and your family Your dream desk setup and all the tools you need to be your most productive self World‑class Playa Vista office with the benefit of in‑person collaboration with amazing coworkers and flexibility to integrate work and life Real impact opportunity: Work alongside experts from aerospace, new space, and other cutting‑edge industries to make a lasting difference Ready to join a team where your contributions matter and your future is bright? Let's build something extraordinary together. Equal Opportunity Employer Apex Technology, Inc. is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. Candidates and employees are always evaluated based on merit, qualifications, and performance. We will never discriminate on the basis of race, color, gender, national origin, ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status. Compensation Range: $125K - $155K #J-18808-Ljbffr Apex - Satellite Platforms