Millennium Space Systems

Sr. Thermal Systems Engineer

Engineering - El Segundo, CA - Full Time

Join our small, close knit engineering team developing advanced space missions as a Senior Thermal Systems Engineer. Millennium Space Systems designs and develops small satellites and other unique space systems. Thermal Engineers perform all spacecraft thermal system configuration, design, analysis, and test. Spacecraft thermal subsystem elements includes all passive and active means of controlling the satellite’s system, subsystem, and component environments within both operating and survival limits during all pertinent system lifetime activities. The Thermal Engineer supports the Spacecraft Development Program Manager and Chief Systems Engineer with spacecraft design, configuration, layout, and analyses. Our Thermal Engineers are involved with developing requirements, design, analysis, and development through system integration, and into flight operations.

  • Responsibilities:
    • Performs spacecraft thermal design and analysis at the subsystem and system level 
    • Develops systems and spacecraft element thermal models and exercises those models to predict thermal loads, impacts, and calculate temperature margins to support system design.
    • Identifies all materials, processes, and facilities to achieve a qualified spacecraft thermal design and operation
    • Manages thermal qualification testing on spacecraft systems and components including test design, test conduct, data reduction, analysis, and reporting.
    • Manages all thermal design, development, and test activities and directs junior engineering support to accomplish all detailed design / analysis while incorporating other system requirements
    • Mentor junior thermal engineers
    • Coordinates efforts with consultants when necessary
  • Minimum Qualifications:
    • Masters degree in Mechanical or Aerospace Engineering
    • 15+ years experience with spacecraft thermal system design and/or analysis
    • Preference to candidates with active TS/SCI clearance
    • Advanced proficiency with Thermal Desktop
    • Familiarity with ANSYS, SINDA/FLUINT, MATLAB, and/or other analysis tools desired
    • Ability to perform complex analyses on structures, mechanisms, electronics, propulsion, and other systems
    • Experience designing thermal environmental testing for units, subsystems, and/or space vehicles


  • Millennium is DDTC-registered, ITAR-compliant Company. This position is located at a facility that requires special access. Applicants MUST be U.S. citizens and eligible for a security clearance. Additionally, applicants must be willing to apply for and maintain a security clearance.
  • We encourage veterans, disabled veterans and disabled individuals to apply for any open position for which they feel they are qualified.
  • We are proud to be an Affirmative Action/Equal Opportunity Employer. 
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