At Relativity Space, we’re building rockets to serve today’s needs and tomorrow’s breakthroughs. Our Terran R vehicle will deliver customer payloads to orbit, meeting the growing demand for launch capacity. But that’s just the start. Achieving commercial success with Terran R will unlock new opportunities to advance science, exploration, and innovation, pioneering progress that reaches beyond the known. Joining Relativity means becoming part of something where autonomy, ownership, and impact exist at every level. Here, you're not just executing tasks; you're solving problems that haven’t been solved before, helping develop a rocket, a factory, and a business from the ground up. Whether you’re in propulsion, manufacturing, software, avionics, or a corporate function, you’ll collaborate across teams, shape decisions, and see your work come to life in record time. Relativity is a place where creativity and technical rigor go hand in hand, and your voice will help define the stories we’re writing together. Now is a unique moment in time where it’s early enough to leave your mark on the product, the process, and the culture, but far enough along that Terran R is tangible and picking up momentum. The most meaningful work of your career is waiting. Join us. About the Team:  The Interplanetary Sciences Program was established to expand access to scientific exploration across our solar system. Its mission is to make planetary research faster, more affordable, and more capable than ever before by rethinking how science missions are designed, built, and operated. The program aims to enable scientists to send instruments to distant worlds without decades of development or prohibitive costs. By creating a sustainable model for interplanetary exploration, we are transforming space science from an occasional event into a continuous process of discovery that accelerates knowledge, broadens participation, and inspires the next generation of explorers. About the Role: As a Senior Avionics Mechanical Engineer, you will own the design, development, and delivery of all mechanical hardware supporting our next-generation space science avionics platforms. This includes enclosures, mounting structures, thermal accommodations, and interfaces to spacecraft systems. You will be responsible for ensuring the delivered Avionics can survive launch and space environments, and for solving complex thermal and structural challenges in tight, mass-efficient packaging. This is a hands-on role for a self-driven engineer who thrives in a fast-paced, prototype-heavy environment. You’ll work from first principles to rapidly iterate on designs, perform analysis and testing, and lead the delivery of flight-ready avionics mechanical systems.   About You: • Bachelor’s or Master’s degree in Mechanical Engineering, Aerospace Engineering, or a related field • 5+ years of experience in mechanical design, packaging, or thermal management for aerospace or ruggedized electronic systems • Proven ability to deliver mechanical systems from concept through qualification and flight • Proficiency with CAD (SolidWorks, NX, or equivalent) and analysis tools for structural and thermal performance • Hands-on experience building, testing, and debugging hardware in a lab environment • Strong communication skills and comfort working cross-functionally in a fast-paced, rapidly iterating team environment Nice to haves but not required:   • Familiarity with NASA or other spaceflight structural verification standards, environmental testing and qualification • Experience designing mechanical systems for spaceflight avionics or payloads • Experience with high-density electronics cooling (conduction, heat pipes, cold plates) • Knowledge of materials and processes for vacuum and radiation environments At Relativity Space, we are committed to transparency and fairness in our compensation practices. Actual compensation will be determined based on experience, qualifications, and other job-related factors. Compensation is only one part of our total rewards package. Relativity Space offers competitive salary and equity, a generous PTO and sick leave policy, parental leave, an annual learning and development stipend, and more! To see some of the benefits & perks we offer, please visit here. Hiring Range: $129,000—$193,000 USD We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. If you need a reasonable accommodation, please contact us at accommodations@relativityspace.com. Please note: Relativity Space does not accept unsolicited resumes, candidate profiles, or referrals from recruitment agencies or search firms. Any unsolicited submission - via email, our website, social media, or directly to an employee - will be deemed the property of Relativity Space, and no fee will be owed absent a current, fully executed agreement with Talent Acquisition that specifically authorizes submissions for the applicable role.