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 Thermal Engineer within the Interplanetary Sciences Program at Relativity Space, you will own the development and application of the spacecraft thermal model that directly guides the design, qualification, and operation of an interplanetary spacecraft. You will define the thermal architecture from first principles, translate mission environments and operational concepts into hardware requirements, and serve as the thermal technical authority across the vehicle lifecycle. This role spans early architecture and trade studies through test correlation, flight qualification, and mission operations, and requires strong technical judgment, analytical skills, autonomy, and systems-level thinking.

Essential Duties and Responsibilities:

• Develop, maintain, and mature integrated spacecraft thermal models at the vehicle, subsystem, and component levels

• Define thermal architectures and requirements and iterate hardware designs in collaboration with cross-disciplinary engineering teams

• Generate flight temperature predictions, margins, and off-nominal analyses, and communicate actionable guidance to the broader engineering team

• Ensure spacecraft payloads remains within operating and survival limits across all mission phases using robust passive and active thermal control strategies

• Correlate thermal models to component, subsystem, and vehicle-level test and/or flight data

About You:

• Bachelor’s or Master’s degree in Aerospace Engineering, Mechanical Engineering, or a closely related field

• 5+ years of experience developing and applying thermal models for spacecraft or flight hardware

• Proficiency with spacecraft thermal analysis tools such as Thermal Desktop, ANSYS, or other software

• Experience anchoring thermal models to test and/or flight data and using results to drive design decisions

• Strong understanding of lumped-parameter (0D/1D) thermal networks and appropriate use of higher-fidelity methods

• Effective technical communicator with demonstrated success working cross-functionally in fast-paced environments

Nice to haves but not required:

• Familiarity with spaceflight thermal margin, qualification, and verification standards (e.g. SMC-S-016)

• Experience planning or executing spacecraft environmental testing, including TVAC

• Experience across a full spacecraft lifecycle, from concept development through on-orbit operations

• Prior experience supporting flight thermal predictions or mission operations

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:$132,000—$181,500 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.