Lead, Mechanical Engineer (Thermal) - Space Vehicle and Payloads

L3Harris is dedicated to recruiting and developing high-performing talent who are passionate about what they do. Our employees are unified in a shared dedication to our customers’ mission and quest for professional growth. L3Harris provides an inclusive, engaging environment designed to empower employees and promote work-life success. Fundamental to our culture is an unwavering focus on values, dedication to our communities, and commitment to excellence in everything we do.

L3Harris is the Trusted Disruptor in defense tech. With customers’ mission-critical needs always in mind, our employees deliver end-to-end technology solutions connecting the space, air, land, sea and cyber domains in the interest of national security.

Relocation: Relocation assistance is available to qualified applicants

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Job Description

L3Harris is seeking an experienced and highly accomplished Lead Thermal Engineerto lead spacecraft‑level thermal design, modeling, and analysis activities for advanced space based electro-optical missions. This role is responsible for architecting and validating thermal solutions that ensure mission success across multiple orbital environments. The ideal candidate is a recognized technical expert capable of driving complex spacecraft thermal strategy, mentoring engineers, and collaborating across multidisciplinary teams.

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Essential Functions

• Serve as the technical lead for spacecraft‑level thermal design, defining architecture, strategies, and requirements for high‑reliability space vehicles.
• Develop detailed thermal models and analyses for all mission phases, including worst‑case hot/cold environments, eclipse conditions, orbital variations, and mission‑specific scenarios.
• Lead creation and validation of thermal control hardware - including radiators, coatings, heat pipes, surface finishes, insulation, heaters, and conductive interfaces.
• Own thermal performance budgets and flow‑down of requirements to payloads, avionics, structures, and propulsion subsystems.
• Evaluate thermal impacts of system trades, configuration changes, power profiles, and operational timelines.
• Direct development of thermal math physics models using industry-standard tools such as Thermal Desktop, Flowtherm,SINDA/FLUINT, ESATAN‑TMS, or equivalent.
• Provide leadership during spacecraft hardware build, integration, and test - including thermal vacuum (TVAC) planning, execution, anomaly resolution, and correlation of test results to analysis.
• Guide environmental considerations for space platforms including radiation, conduction, convection-free behavior, material properties, surface degradation, and mission life effects.
• Act as a cross-functional leader, collaborating closely with systems engineering, mechanical design, power, RF, digital hardware, manufacturing, and mission assurance teams.
• Mentor junior and mid‑level engineers, establishing best practices and driving continuous improvement in thermal engineering processes.
• Prepare high‑quality documentation including thermal requirements, analysis reports, review packages, test plans, and verification matrices.
• Ability to obtain a US security clearance

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Qualifications

• Bachelor of Science Degree in Engineering and a minimum of 9 years of prior relevant experience. Graduate Degree in Engineering and a minimum of 7 years of prior related experience. In lieu of a degree, minimum of 13 years of prior related experience.
• 5+ years professional experience using Thermal Desktop
• Prior or current professional experience with thermal design and analysis for space environment/products
• 2+ years of experience as an IPTL or providing technical leadership to an engineering team

Preferred Additional Skills

• Experience designing for a space environment.
• Hold a current security Clearance or the ability to obtain a security clearance
• Deep understanding of spacecraft materials, thermal coatings, MLI, conductive interfaces, and active thermal control elements.
• Demonstrated success in developing, validating, and correlating thermal models to TVAC results.
• Ability to lead design reviews, guide complex decision-making, and communicate clearly with customers, leadership, and engineering teams.
• Experience working on government, DoD, or national security space missions.
• Knowledge of mission-specific environments such as GEO, LEO, cislunar, or deep space.
• Broad knowledge of thermal-fluids physics including heat conduction and convection of multi-phase flows
• Experience creating and overseeing the development of thermal testing control logic in SINDA/FLUENT
• Familiarity with structural-thermal-optical (STOP) analysis, deployment mechanism thermal behavior, or thermal considerations in RF/high‑power payloads.
• Experience with reliability assessments, derating, and long‑duration thermal performance modeling.

L3Harris Technologies is proud to be an Equal Opportunity Employer. L3Harris is committed to treating all employees and applicants for employment with respect and dignity and maintaining a workplace that is free from unlawful discrimination. All applicants will be considered for employment without regard to race, color, religion, age, national origin, ancestry, ethnicity, gender (including pregnancy, childbirth, breastfeeding or other related medical conditions), gender identity, gender expression, sexual orientation, marital status, veteran status, disability, genetic information, citizenship status, characteristic or membership in any other group protected by federal, state or local laws. L3Harris maintains a drug-free workplace and performs pre-employment substance abuse testing and background checks, where permitted by law.

Please be aware many of our positions require the ability to obtain a security clearance. Security clearances may only be granted to U.S. citizens. In addition, applicants who accept a conditional offer of employment may be subject to government security investigation(s) and must meet eligibility requirements for access to classified information.

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