Propulsion Engineer (Hellbender)

Firefly Aerospace; Cedar Park (TX); On-site; USD 90,000 - 120,000; Full time

Job summary

A leading aerospace company is seeking a Hellbender Responsible Engineer to drive the development of a next-generation liquid rocket engine. This role emphasizes leadership, technical expertise, and collaboration across teams to ensure the engine meets mission objectives. The ideal candidate will have a strong background in aerospace engineering and experience in propulsion systems, with a focus on innovation and efficiency.

Benefits

Health Insurance

Dental Insurance

Vision Insurance

Parental Leave

Educational Reimbursement

Short Term Disability

Flexible PTO

Qualifications

• 3+ years of relevant experience in aerospace or mechanical engineering.
• Strong engineering fundamentals in flow, heat transfer, and combustion devices.

Responsibilities

• Take full ownership of the Hellbender engine system.
• Lead a team of propulsion engineers in design and testing.

Skills

Leadership

Problem Solving

Communication

Education

Bachelor’s degree in aerospace engineering

Bachelor’s degree in mechanical engineering

Tools

Jira

CAD

Python

LabVIEW

Job description

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As an end-to-end responsive space company, Firefly Aerospace is on a mission to enable our world to launch, land, and operate in space – anywhere, anytime. Our small- to medium-lift launch vehicles, lunar landers, and orbital vehicles allow us to service the entire lifecycle of government and commercial missions from low Earth orbit to the Moon and beyond. We utilize carbon composite structures, patented propulsion technologies, and common components across our vehicles to iterate quickly, improve reliability, and deliver payloads at a lower cost.

ABOUT THE ROLE

As the Hellbender Responsible Engineer, you will take extreme ownership of the Hellbender liquid rocket engine program, driving its development from concept to flight. You be the single point of contact for a cross-functional team to design, analyze, test, and produce a next-generation engine that emphasizes simplicity, reliability, and performance while minimizing cost. This role requires deep technical expertise, strong leadership, and the ability to make critical decisions in a fast-paced environment. You will collaborate with structures, fluid systems, avionics, and vehicle teams to ensure the engine meets mission objectives, embracing complex challenges and synthesizing information to deliver innovative propulsion solutions.

RESPONSIBILITIES

• Take full ownership of the Hellbender engine system, serving as the primary engineer responsible for its design, development, and test.
• Lead a team of propulsion engineers in engine architecture, including design, analysis, and testing, to meet performance and reliability goals.
• Serve as the technical expert for the Hellbender program during design reviews, failure investigations, and program milestones.
• Collaborate with manufacturing, build, and test teams to streamline production and testing processes, ensuring design for manufacturability.
• Develop innovative design concepts for propulsion components and tooling that reduce part count, complexity, and cost.
• Identify and trade strategies to meet design requirements, balancing technical merit, risk, cost, and schedule.
• Support the development of manufacturing, integration, and test processes, including work instructions and test procedures.
• Provide hands-on support during engine builds and testing, iterating designs based on test outcomes.
• Communicate risks, trade studies, and solutions to cross-functional teams and leadership to minimize development and operational risks.
• Create and release P&IDs, CAD, drawings, and daily work packets
• Work directly with vendors to source commercially available items and track schedule and deliveries
• Own the project schedule by driving team scrums, coordinating delivery of materials and work execution, and updating progress against high-level milestones to share with Firefly leadership

QUALIFICATIONS

Required

• Bachelor’s degree in aerospace engineering, mechanical engineering, or a related field
• 3+ years of relevant experience in aerospace or mechanical engineering, with a focus on propulsion or fluid systems.
• Strong engineering fundamentals in compressible and incompressible flow, heat transfer, combustion devices, rocket engine cycles, and mechanics.
• Proven leadership in solving complex technical problems and managing cross-functional teams.
• Experience across the full product lifecycle, from conceptual design to testing and production.
• Ability to manage multiple tasks, prioritize effectively, and work independently in a dynamic environment.
• Strong interpersonal and communication skills for collaborating with diverse teams and presenting to leadership.
• Hands-on experience building complex systems
• Strong leadership skills with the ability to manage and motivate cross-functional teams
• Excellent communication skills with a focus on proactive updates and risk management
• Working knowledge of fabrication and manufacturing techniques such as machining, welding, inspection, non-destructive evaluation, and assembly integration
• Strong problem-solving skills and the ability to take initiative and work independently
• Attention to detail and strong organizational skills

Desired Qualifications

• Advanced degree in mechanical, aerospace, or equivalent field
• Experience with liquid rocket engine development, design, testing, or flight operations.
• Hands-on experience with engine subcomponents (valves, regulators, tubing) or pressurized systems.
• In-depth knowledge of manufacturing processes, change management, and risk mitigation strategies
• Experience with tools such as Jira and other project management or configuration management software
• Familiarity with CAD and configuration management tools (e.g., Siemens NX, Teamcenter).
• Proficiency in software tools such as Python, LabVIEW, GFSSP, or Winplot for data analysis and control.

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.