Thermal Analysis Engineer

About Portal Portal Space Systems is on a mission to expand humanity’s freedom of movement in space. We’re building the spacecraft that makes that mission possible. From our Bothell, WA headquarters, we design vehicles with the maneuverability, resilience, and adaptability needed for the next era of orbital operations. Every system we build is in service of a simple idea: space should be more accessible, responsive, and capable. Joining Portal means stepping into a team that believes in bold engineering, fast iteration, and the power of small groups to change what’s possible. If you want your work to directly shape the future of in-space mobility, join us. Position Summary The Thermal Analysis Engineer develops and maintains the integrated thermal model for a spacecraft and uses it to guide vehicle design, test, and verification. This is an individual-contributor role for an engineer with 2–3 years of relevant experience who is ready to lead whole-spacecraft thermal modeling with support from senior technical leadership. The engineer will work across subsystem boundaries, track spacecraft power use and heater demand, predict temperature margins, and own correlation of the vehicle thermal model using thermal-vacuum test data. Responsibilities • Lead the development, configuration control, and maintenance of a whole-spacecraft thermal mathematical model in Thermal Desktop and SINDA/FLUINT. • Define and analyze orbital, mission, operational, survival, hot-case, and cold-case thermal environments. • Predict component and structural temperatures, identify low-margin hardware, and recommend practical thermal design changes. • Analyze conductive and radiative interfaces, heaters, insulation, coatings, radiators, and other passive and active thermal-control features. • Size heaters and quantify thermal-control power demand. • Track the spacecraft electrical power budget in coordination with power-system and subsystem owners, reconcile assumptions, and identify inconsistencies that affect thermal performance. • Develop thermal predictions, temperature plateaus, instrumentation recommendations, limits, and success criteria for thermal-vacuum and thermal-balance testing. • Own post-test thermal model correlation, including comparison of predicted and measured temperatures, documentation of correlation changes, and updated flight predictions and margins. • Produce clear thermal analysis reports and verification evidence for design reviews, test readiness reviews, qualification or acceptance reviews, and flight readiness reviews. • Support trade studies, anomaly investigations, late configuration changes, and cross-functional design decisions. • Maintain traceability among model inputs, vehicle configurations, analysis results, test data, and verification artifacts. Basic Qualifications • Bachelor’s degree in mechanical engineering, aerospace engineering, or a related technical discipline. • 2 + years of professional spacecraft thermal analysis experience. Preferred Qualifications • Experience leading the thermal model for a complete spacecraft or similarly complex integrated vehicle. • Experience supporting spacecraft TVAC or thermal-balance testing. • Familiarity with Python for data processing, model automation, or test-data analysis. • Experience with requirements verification, configuration-controlled analysis, or formal spacecraft design reviews. • Familiarity with spacecraft electrical power systems, heater-control logic, and flight telemetry. • Experience developing or maintaining vehicle-level spacecraft thermal models using Thermal Desktop and SINDA/FLUINT. • Experience supporting a spacecraft flight program through design, test, integration, or flight readiness. • Experience tracking or contributing to a spacecraft electrical power budget and reconciling inputs from multiple subsystem owners. • Working knowledge of spacecraft heat-transfer fundamentals, orbital thermal environments, thermal-control hardware, and temperature-margin assessment. • Experience comparing analysis predictions with thermal test data and correlating a thermal model. • Ability to work across disciplines and communicate assumptions, risks, margins, and recommendations clearly. Work Expectations • Primarily an individual-contributor role with ownership of assigned vehicle-level thermal analysis products. • Occasional travel and off-hours support may be required during spacecraft test campaigns. ITAR Statement This position may involve access to technical data and defense-related materials controlled under the International Traffic in Arms Regulations (ITAR). Eligibility to access ITAR-controlled items requires that candidates be U.S. persons, which includes U.S. citizens, lawful permanent residents, and other protected individuals as defined by U.S. law. Employment is contingent upon verification of ITAR eligibility and, where applicable, obtaining any required export authorization or license. Equal Opportunity Statement All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran.