Millennium Space Systems, A Boeing Company

Thermal Systems Engineer - Principal

Thermal Engineering - El Segundo, CA - Full Time

Company Overview 

Millennium Space Systems, A Boeing Company delivers affordable, high-performance space systems for demanding customers. At Millennium, you will be part of a close-knit team working on exciting technological problems. We work in an open environment where ideas are shared across all disciplines, and there are ample opportunities for advancement based on demonstrated excellence. Superstars are welcome.

Job Summary

Thermal Engineers perform all spacecraft thermal system configuration, design, analyses, test, and flight operations while supporting the Spacecraft Development Program Managers and Chief Systems Engineer. The Senior Thermal Systems Engineer will not only provide guidance to junior thermal engineers but also provide subject matter expertise to complex engineering challenges. Additionally, this engineer will provide general engineering support to the team in modeling, analysis, document generation, environmental testing, and other roles. 

  • Responsibilities:
    • Performs spacecraft thermal design and analyses at the board, component, subsystem, and system level 
    • Develops systems and spacecraft element thermal models to predict thermal loads, impacts, and temperature margins to support system design. 
    • Brief design and analysis materials to program managers, customers, and/or sponsors.
    • Identifies all materials, processes, and facilities to achieve a qualified spacecraft thermal design and operation
    • Oversees and/or manages the thermal verification testing on spacecraft systems and components including test design, test conduct, data reduction, analysis, and reporting.
    • Provides support, guidance, and management of all thermal designs, developments, and test activities to junior engineering support.
    • Mentors junior thermal engineers in basic and advanced thermal engineering concepts.
    • Supports the development of tools to aide in conceptual designs and post-processing analysis.
    • Assist in proposal and business development efforts
    • Coordinates efforts with consultants when necessary


  • Minimum Qualifications:
    • Masters degree in Mechanical Engineering, Aerospace Engineering, Physics, or other relevant fields
    • 20 or more years of experience in the design, development, analysis, implementation, testing, and/or operation of spacecraft thermal systems or other related complex thermal systems
    • Ability to obtain and maintain a TS/SCI Security Clearance; Preference to candidates with active TS/SCI clearance
    • Ability to perform complex analyses on structures, mechanisms, electronics, propulsion, and other systems
    • Advanced proficiency with Thermal Desktop and/or SINDA/FLUINT
    • Familiarity a plus with TSS, Thermica, ANSYS, MATLAB, or other FEA analysis tools
    • Experience designing thermal environmental testing for units, subsystems, and/or space vehicles

Benefits and Perks

Millennium Space Systems, A Boeing Company offers a very competitive benefits package to include medical, dental, vision, and 401k plan. Relocation assistance to Southern California can be provided. 

Before applying, please note:

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 are proud to be an Affirmative Action/Equal Opportunity Employer. We encourage veterans, disabled veterans and disabled individuals to apply for any open position for which they feel they are qualified.

Apply: Thermal Systems Engineer - Principal
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