Thermal Engineer; Senior

About the Role

Requirements:

• U.S. Persons status is required as this position requires access to export-controlled data.

• Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, or a related field.

• 5+ years of experience in thermal engineering, preferably in spacecraft or aerospace systems.

• Proficiency with thermal analysis tools, especially Ansys Thermal Desktop.

• Strong understanding of spacecraft thermal control systems.

• Familiarity with thermal margin definitions per MIL-STD, Aerospace TOR, or vendor command media.

• Proficiency with Siemens NX and Teamcenter.

• Experience with thermal vacuum testing, thermal test instrumentation, and data acquisition systems.

• Working knowledge of 2-phase thermal control systems.

• Strong analytical, problem-solving, and communication skills.

• Ability to critically assess thermal model results and correlate with test or flight data.

• Capable of managing multiple concurrent projects in a fast-paced environment.

Responsibilities:

• Develop and maintain spacecraft-level thermal models using Ansys Thermal Desktop.

• Evaluate and validate thermal analysis results to ensure accuracy and alignment with mission requirements.

• Drive innovation by identifying ways to reduce cost and complexity of legacy thermal subsystems.

• Plan and execute thermal subsystem milestone reviews (e.g., SRR, PDR, CDR, MRR).

• Oversee thermal flight hardware integration and ensure quality control during build and test.

• Design, plan, and execute thermal vacuum tests at both component and system levels.

• Correlate test and flight data to thermal models to refine accuracy and performance predictions.

• Collaborate cross-functionally with mechanical, systems, and avionics teams to meet thermal requirements across the spacecraft lifecycle.

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.

• 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 BBQs, pickleball tournaments, run club, and social 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 EV chargers, 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.

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.