Principal Propulsion Engineer (Liquid Engines)

Firefly Aerospace; Town of Texas (WI); On-site; USD 120,000 - 150,000; Full time

Benefits offered by this job

Generous health, dental, and vision plans

Parental leave

Educational reimbursement

Flexible PTO options

Job summary

A leading space transportation company is seeking a Principal Propulsion Engineer to drive the lifecycle of launch vehicle engine systems. Responsibilities include hardware design, testing, and leading innovative propulsion solutions. Candidates need 8+ years in propulsion systems, deep understanding of fluid dynamics, and strong problem-solving skills. Join an innovative team in a fast-paced environment and be part of a mission to enable global space operations.

Qualifications

• 8+ years of experience developing launch vehicle propulsion systems.
• Experience testing or operating complex engineering systems.
• Deep knowledge of engineering fundamentals and problem-solving skills.

Responsibilities

• Demonstrate full ownership of launch vehicle engine system hardware from concept to flight.
• Serve as the propulsion representative for Alpha engine testing.
• Plan, coordinate, and execute development testing of flight hardware.

Skills

Fluid dynamics understanding

Problem-solving

Communication skills

Technical writing

Hands-on hardware experience

Education

B.S. in Mechanical, Aerospace, or related engineering discipline

Tools

Data acquisition systems

Job description

Principal Propulsion Engineer (Liquid Engines)

As an end‑to‑end space transportation company, Firefly Aerospace is on a mission to enable our world to launch, land, and operate in space – anywhere, anytime. Our launch vehicles, lunar landers, and orbital vehicles provide government and commercial customers with full mission services from low Earth orbit to the surface of the Moon and beyond. Headquartered in north Austin, Texas, Firefly is looking for passionate, hardworking innovators to join our team and help fuel our successful trajectory into space.

About the Role

The Alpha Engines team is responsible for the design, integration, and operation of the Reaver and Lightning engines. As a Principal Responsible Engineer, you will work across the full lifecycle of hardware, including requirements definition, design, analysis, development, test, and qualification of the engine systems. In this role, you will lead CAD design and analysis efforts, collaborate with fabrication and integration teams to build and assemble the system, and support vehicle testing and launch operations. The Alpha Engines team requires deep technical knowledge, ownership of hardware from concept to flight, and clear communication with cross‑functional partners including structures, propulsion, avionics, and vehicle systems. The successful candidate will be a self‑starter who enjoys challenging assumptions, thrives in a fast‑paced development environment, and seeks to make impactful contributions to Firefly’s mission.

Responsibilities

• Demonstrate full ownership of launch vehicle engine system hardware from concept to flight
• Serve as the propulsion representative for Alpha engine testing, stage testing, and launch operations
• Author and lead test readiness, launch readiness, and data review presentations
• Continuously build and iterate on tools to optimize efficiency, performance, and predictability of Alpha operations
• Lead development of innovative design concepts for propulsion integration and operations that reduce complexity and maximize reliability within program constraints.
• Author and present detailed design review presentations to internal and external stakeholders
• Plan, coordinate, and execute development, qualification, and acceptance testing of flight hardware, including data analysis and reviews
• Identify system‑level risks, perform trade studies, and drive decisions to ensure successful vehicle operation
• Develop and maintain automation tools and test data analysis capabilities
• Collaborate with manufacturing and integration teams to develop processes, work instructions, and test procedures, and provide direct build support

Qualifications

Required

• B.S. in Mechanical, Aerospace, or related engineering discipline
• 8+ years of experience developing launch vehicle propulsion systems
• Experience testing or operating complex engineering systems
• Thorough understanding of fluid dynamics and thermodynamics
• Deep knowledge of engineering fundamentals and a demonstrated history of applying first principles to arrive at simple, robust solutions
• Excellent problem‑solving, communication, and technical writing skills.
• Hands‑on experience with hardware design, fabrication, and testing
• Working knowledge of manufacturing, fabrication, integration, and quality control relevant to fluid components (such as machining, inspection, assembly, testing, etc.)
• Knowledge of fluid components such as valves, regulators, pressure transducers, tubing, pressurized hardware, seals, and instrumentation and experience performing fluid systems sizing analysis with such components
• Experience developing and formalizing procedures for complex, multistep, high‑impact operations
• Proven ability to rapidly develop solutions with partially defined or evolving requirements

Desired Qualifications

• Advanced degree in Mechanical Engineering, Aerospace Engineering, or equivalent field
• 10+ years of experience developing launch vehicle or spacecraft propulsion systems
• In‑depth knowledge of cryogenic, high‑pressure, or high‑temperature system operations
• Experience with fluid system subcomponent or pressurized component development, design, or testing (such as valves, regulators, piping systems, pumps, etc.)
• Experience in working with data acquisition systems and test instrumentation including pressure transducers, thermocouples, resistance temperature detectors (RTDs), flow meters, load cells, and accelerometers
• Experience reducing the complexity of large integrated assemblies to reduce part count, cost, and lead time
• Demonstrated experience with full hardware lifecycle ownership, from blank‑sheet design through full operation

Benefits

Firefly offers outstanding benefits for our employees, including generous health, dental and vision plans with low plan deductibles, parental leave, educational reimbursement, short term disability, and flexible PTO options.

To conform to U.S. Government space technology export regulations, including the International Traffic in Arms Regulations (ITAR) you must be a U.S. citizen, lawful permanent resident of the U.S., protected individual as defined by 8 U.S.C. 1324b(a)(3), or eligible to obtain the required authorizations from the U.S. Department of State.

Firefly Aerospace, Inc. is an Equal Opportunity Employer; employment with Firefly is governed based on merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.