Principal Thermal Engineer Jobs (NOW HIRING)

Date Posted: 2026-08-03 Country: United States of America Location: US-CA-EL SEGUNDO-E01 ~ 2000 E El Segundo Blvd ~ BLDG E01 Position Role Type: Onsite U.S. Citizen, U.S. Person, or Immigration Status Requirements: The ability to obtain and maintain a U.S. government issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance Security Clearance Type: DoD Clearance: TS/SCI Security Clearance Status: Active and existing security clearance required after day 1

At RTX, the world's largest aerospace and defense company, 185,000 great minds are united by purpose and inspired to make a difference solving the world’s most complex problems. With our three market leading businesses, world-class operations and investments in research and development, we offer capabilities and opportunity no one else can. Together, we push the boundaries of known science and find new ways to connect and protect our world. Raytheon brings the strength of more than 100 years of experience and renowned engineering expertise to meet the needs of today’s mission and stay ahead of tomorrow’s threat. We deliver solutions that help our nation and allies defend freedoms and deter aggression, creating a safer, more secure world. Join us and help shape the future of aerospace and defense. At Raytheon, the foundation of everything we do is rooted in our values and a higher calling – to help our nation and allies defend freedoms and deter aggression. We bring the strength of more than 100 years of experience and renowned engineering expertise to meet the needs of today’s mission and stay ahead of tomorrow’s threat. Our team solves tough, meaningful problems that create a safer, more secure world.

Job Summary The Mechanical Analysis and Test (MA&T) Department is responsible for ensuring structural and thermal design robustness across the Raytheon portfolio of products. From preliminary concepts to fielded weapon system support, MA&T delivers innovative structural and thermal engineering solutions utilizing methods ranging from classical fundamental & empirically based techniques to state-of-the-art finite element methods leveraging industry leading commercial tools; all complimented and validated by tests executed in a manner to ensure cost effective yet technically balanced solutions. The MA&T team is seeking a mid-level career Senior Principal Thermal Engineer to join our MA&T Center in El Segundo, CA. As a Senior Principal Thermal Engineer, you will be responsible for detailed thermal analysis on products throughout their lifecycle from initial design trade studies and proposals through qualification testing to enduring production support. The analyses will cover a wide range of difficult problems, requiring solutions that are imaginative, thorough, practicable, and consistent with organization objectives. The analysis tasks will span the spectrum from classical hand analyses to detailed analyses requiring the use of finite element analysis software. A Thermal Engineer of this salary grade is expected to have a high level of technical competence with thermodynamic principles. The Thermal Engineer will be held accountable for completing his/her work within the agreed upon cost and schedule. Additionally, the selected candidate will be expected to present their work for peer reviews and to be a peer reviewer for other engineers’ work. Finally, the engineer is expected to plan and support tests, perform data reduction and engage in thermal model correlation.

• Perform Hand Calculations to determine scope of higher detail analysis models
• Perform detailed thermal analyses to solve various program thermal challenges
• Generate test plans required to validate analyses and verify hardware compliance to customer requirements
• Analyze test data to validate and correlate models
• Work with experienced analysts on problems of moderate complexity to provide the answers needed under program cost and schedule constraints
• Review your work with peers to ensure technical accuracy
• Present results to internal, external, and government customers
• Generate detailed documentation of work and archive for reference
• Act as a technical leader (help define/refine and/or develop MA&T department technical processes and tools) and/or lead analysis/test teams

• Typically requires a degree in Science, Technology, Engineering or Mathematics (STEM) and a minimum of 10 years of prior relevant or
• An Advanced Degree in a related field and minimum 7 years’ experience
• Experience in thermal analysis with any of the following tools: ANSYS, FloTHERM, PATRAN, Thermal Desktop/SINDA or equivalent
• Experience with thermal analysis of electro-optical sensor systems
• Experience in mechanical principles to solve classical thermal analysis solutions both inside and outside of finite element tools and an ability to work independently and manage multiple priorities
• Demonstrated experience in thermal testing: planning, organization, execution, data reduction and correlation
• Demonstrated experience in leading a large team (>6) of thermal analysts on major program efforts
• Wide breadth of knowledge of space vehicle payload thermal architectures and ability to influence architecture design early in the development cycle
• Ability to obtain a U.S. government issued security clearance. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance
• Ability to work on-site in a closed and secured space in El Segundo, CA

• Master’s Degree in Mechanical Engineering or Aerospace Engineering,12+ years of professional experience in the thermal analysis of complex systems that require collaboration across multiple engineering disciplines
• Demonstrated experience in leading thermal testing: Planning, organization, execution, data reduction and correlation
• Experience with planning and performing Thermal Vacuum (TVAC) testing
• Experience with orbital thermal analysis using Thermal Desktop or equivalent
• Experience with solid modeling CAD tools such as CREO or equivalent
• Earned Value Management System knowledge
• Experience in supporting EACs, BOEs and proposals
• Experience presenting to external customers
• Advanced degree in aforementioned disciplines. ABET is the preferred, although not required, accreditation standard

• Whether you’re just starting out on your career journey or are an experienced professional, we offer a robust total rewards package that goes above and beyond with compensation; healthcare, wellness, retirement and work/life benefits; career development and recognition programs.
• Some of the superior benefits we offer include parental (including paternal) leave, flexible work schedules, achievement awards, educational assistance, and child/adult backup care.
• Onsite: Employees who are working in Onsite roles will work primarily onsite. This includes all production
• Relocation Eligible - relocation assistance is available for this position
• As part of our commitment to maintaining a secure hiring process, candidates may be asked to attend select steps of the interview process in-person at one of our office locations, regardless of whether the role is designated as on-site, hybrid or remote.
• The salary range for this role is 145,600 USD - 276,800 USD.
• The salary range provided is a good faith estimate representative of all experience levels.
• RTX considers several factors when extending an offer, including but not limited to, the role, function and associated responsibilities, a candidate’s work experience, location, education/training, and key skills.
• Hired applicants may be eligible for benefits, including but not limited to, medical, dental, vision, life insurance, short-term disability, long-term disability, 401(k) match, flexible spending accounts, flexible work schedules, employee assistance program, Employee Scholar Program, parental leave, paid time off, and holidays.
• Specific benefits are dependent upon the specific business unit as well as whether or not the position is covered by a collective-bargaining agreement.
• Hired applicants may be eligible for annual short-term and/or long-term incentive compensation programs depending on the level of the position and whether or not it is covered by a collective-bargaining agreement.
• Payments under these annual programs are not guaranteed and are dependent upon a variety of factors including, but not limited to, individual performance, business unit performance, and/or the company’s performance.
• This role is a U.S.-based role. If the successful candidate resides in a U.S. territory, the appropriate pay structure and benefits will apply.
• RTX anticipates the application window closing approximately 40 days from the date the notice was posted. However, factors such as candidate flow and business necessity may require RTX to shorten or extend the application window.
• RTX is an Equal Opportunity Employer.
• All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability or veteran status, or any other applicable state or federal protected class.
• RTX provides affirmative action in employment for qualified Individuals with a Disability and Protected Veterans in compliance with Section 503 of the Rehabilitation Act and the Vietnam Era Veterans’ Readjustment Assistance Act.

Privacy Policy and Terms: RTX is an aerospace and defense company that provides advanced systems and services for commercial, military and government customers worldwide. It comprises three industry-leading businesses – Collins Aerospace, Pratt & Whitney, and Raytheon. Its 195,000 employees enable the company to operate at the edge of known science as they imagine and deliver solutions that push the boundaries in quantum physics, electric propulsion, directed energy, hypersonics, avionics and cybersecurity. The company, formed in 2020 through the combination of Raytheon Company and the United Technologies Corporation aerospace businesses, is headquartered in Arlington, Virginia.