Propulsion Engineer (Fluid/ Thermal)

Portal Space Systems; Bothell (WA); On-site; USD 120,000 - 165,000; Full time

Job summary

Portal Space Systems is hiring a Fluid/Thermal-focused Propulsion Engineer in Bothell, WA. You will advance thruster, feed system, and tank development with high fidelity CFD and thermal analyses, informing design trades from concept to flight hardware.

Qualifications include a mechanical or aerospace degree and demonstrated CFD experience; NX, STAR-CCM+, GFSSP, and Linux proficiency are preferred. This role emphasizes rigorous first-principles analysis and close collaboration with propulsion

Qualifications

• Bachelor’s or Master’s degree in Mechanical Engineering, Aerospace Engineering, related field or equivalent.
• Experience developing complex CFD models and reduced order fluid/thermal hand calcs.
• Experience communicating analysis assumptions, results, and design implications.

Responsibilities

• Develop high fidelity CFD models to support HEX Thruster and propellant tank development.
• Model complex fluid behavior, including multiphase flow, phase change, and conjugate heat transfer, and tank slosh.
• Build fluid network models of feed systems and utilize these for component sizing and controls development.
• Complete first order hand calcs for simple problems and quick answers.
• Support propulsion test campaigns with pre-test predictions, instrumentation planning, and post-test data reduction and model correlation.
• Predict transient temperature distributions internal to the HEX Thruster as driven by radiation in, re-radiation out, conduction internal to the thruster, and conduction to the bus.
• Identify and design thermal control approaches of the thruster, including radiation absorption design, re-radiation mitigation, and conduction paths

Skills

Fluid mechanics

Thermodynamics

Heat transfer

CFD modeling

First principles

Communication

Education

BSc/MSc in Mechanical or Aerospace Eng

Tools

NX

STAR-CCM+

GFSSP

Linux

Job description

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.

About the Role

We are hiring a Fluid/Thermal-focused Propulsion Engineer to advance thruster, feed system, and tank development. This role is responsible for high fidelity CFD (multiphase, phase change, conjugate heat transfer, slosh) and thermal analysis, developing fluid network models, and supporting component sizing across the feed system. This position works closely with fellow propulsion engineers and analysis experts to inform design trades, predict performance, and drive hardware development from conceptual trades through qualified hardware and flight.

Primary Responsibility – Fluid Analysis

• Develop high fidelity CFD models to support HEX Thruster and propellant tank development
• Model complex fluid behavior, including multiphase flow, phase change, and conjugate heat transfer, and tank slosh
• Build fluid network models of feed systems and utilize these for component sizing and controls development
• Complete first order hand calcs for simple problems and quick answers
• Support propulsion test campaigns with pre-test predictions, instrumentation planning, and post-test data reduction and model correlation

Secondary Responsibility – Thermal Analysis

• Predict transient temperature distributions internal to the HEX Thruster as driven by radiation in, re-radiation out, conduction internal to the thruster, and conduction to the bus
• Identify and design thermal control approaches of the thruster, including radiation absorption design, re-radiation mitigation, and conduction paths

What You Bring To Portal

• Strong foundation in fluid mechanics, thermodynamics, and heat transfer with the ability to apply first principals reasoning and quickly learn new modeling approaches.
• Ability to identify, within the role’s scope, high-impact technical problems and focus analysis efforts where they can most effectively reduce risk, improve performance, and accelerate hardware decisions
• Propensity to solicit and provide peer review, clearly and concisely document results, and communicate implications for the associated hardware

Basic Qualifications

• Bachelor’s or Master’s degree in Mechanical Engineering, Aerospace Engineering, related field or equivalent.
• Experience developing complex CFD models and reduced order fluid/thermal hand calcs.
• Experience communicating analysis assumptions, results, and design implications.

Preferred Qualifications

• Proficiency with NX, STAR-CCM+, GFSSP, and Linux
• Experience with multiphase, conjugate heat transfer, and transient CFD modeling
• Experience with high geometric fidelity thermal modeling
• Experience using test data to correlate analytical models

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.