Mechanical Engineer II

Relativity Space; United States; On-site; USD 104,000 - 156,000; Full time

Benefits offered by this job

Competitive salary

Equity

PTO & sick leave

Parental leave

Learning and development stipend

Job summary

Relativity Space is seeking a Propulsion Test Engineer II to work on Terran R test stands in Mississippi. You’ll design and operate high-energy test articles, collaborating with engineers, technicians, and welders to enable flight readiness and rapid iteration.

The role includes hands-on fabrication, test campaigns, and cross-team problem solving, with a focus on Design & Build, Operations, and Integration in a fast-paced environment.

Qualifications

• Bachelor’s degree in mechanical or aerospace engineering.
• Ability to safely operate common power tools.
• Willingness to travel up to 10% and drive on test sites.

Responsibilities

• Design fluid, gas, and cryogenic systems for test stands and components.
• Conduct test operations on engines and stages and monitor telemetry.
• Develop GUIs, procedures, and data review processes.
• Prepare test articles for testing and manage inspections and non-conformances.
• Support modifications and maintenance on existing facilities.

Skills

Power tool use

Time management

Driver's license

Education

Bachelor’s degree in mechanical or aerospace engineering

Tools

3D modeling

P&ID design

GD&T

Test stand fabrication

Job description

At Relativity Space, we’re building rockets to serve today’s needs and tomorrow’s breakthroughs. OurTerran R vehicle will deliver customer payloads to orbit, meeting the growing demand for launchcapacity. But that’s just the start. Achieving commercial success with Terran R will unlock newopportunities to advance science, exploration, and innovation, pioneering progress that reaches beyondthe 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. Nowis a unique moment in time where it’s early enough to leave your mark on the product, the process, andthe culture, but far enough along that Terran R is tangible and picking up momentum. The mostmeaningful work of your career is waiting. Join us.

About the Team

The Stennis Test team designs, builds, and operates test sites to evaluate Terran R’s high-energy components, rocket engines, and both booster and upper stages. Team members are hands-on with these large-scale, complex systems, pushing hardware to the limits and directly contributing to flight readiness. The work is fast-paced, highly operational, and collaborative. No aerospace experience required—we welcome fresh graduates as well as those with hands-on backgrounds in aviation, automotive, manufacturing, offshore operations, industrial systems, construction, or adjacent industries. As the Stennis Test site scales to meet growing demand, the team plays a critical role in paving the way for routine, reliable flights of Terran R.

About the Role

As a Propulsion Test Engineer II, you will work with test stands and test articles (high-energy components, engines, and full stages) for Terran R. You’ll have the opportunity to see a heavy-lift orbital launch vehicle and its many parts come to life through testing. Test and flight articles are designed and built in our Long Beach factory, then sent to Stennis to undergo rigorous testing. Entry-level engineers at our Stennis facility work in partnership with experienced engineers, technicians, and welders to build and modify test facilities and participate in test campaigns to evaluate complex rocket hardware. You’ll solve a variety of technical problems across broad ranges of timeframe, complexity, and impact, and continuously improve processes to move faster and more efficiently. The role includes three focus areas - Design & Build, Operations, and Integration. You’ll initially be placed on a team in one focus area, with opportunities to work across focuses as you develop in the role, particularly between Operations and Integration which work closely together.

[Design & Build Focus]

1. Design fluid systems (gas, liquid, cryogenic) including Piping & Instruction Diagrams (P&IDs), analysis, and component selection
2. Design structural and mechanical systems including 3D modeling, analysis, and fabrication drawings
3. Source components and develop detailed fabrication work instructions
4. Bring new test stands to life by managing fabrication, activation, and initial operations
5. Design and implement upgrades to operational test stands to enable new test capabilities
6. Maintain test stands through preventive maintenance and rapid response to anomalies & equipment failures

[Operations Focus]

1. Conduct test operations on high-energy components, engines, and stages
2. Control test stand and test article through GUIs and automation while monitoring cameras and telemetry
3. Conduct flight acceptance, qualification, and development testing campaigns to validate designs and continuously improve the rocket
4. Develop and optimize GUIs, procedures, control automation, and data review processes
5. Prepare test articles for testing through inspections, functional checks, leak checks, and managing non-conformances
6. Bring new test stands to life and support modifications and maintenance on existing facilities

Operations Engineers typically work a scheduled morning or evening shift

[Integration Focus]

1. Manage test articles through test prep, post-test processing, and repairs
2. Author work instructions for test articles and coordinate work with technicians and quality inspectors
3. Manage non-conformances, author corrective work instructions, and implement part requirements
4. Maintain work instructions current with evolving build specifications and drive standardization across sites
5. Incorporate feedback and optimize part usage to streamline hardware flow and reduce waste

Integration Engineers typically work a scheduled morning or evening shift

About You

• Bachelor’s degree in mechanical engineering, aerospace engineering, or a related field
  • No aerospace experience needed—we value unique backgrounds and perspectives
• Demonstrated ability to safely operate common power tools
• Ability to deliver on tight schedules, especially when unconventional & creative solutions are necessary
• This role may require travel to production and launch locations, up to 10%
• Valid driver’s license to operate vehicles on the test site

Nice to haves but not required

• Proficiency in 3D modeling and drafting, including GD&T
• Strong engineering fundamentals in Thermal Fluid Systems and Structures
• Hands-on fabrication experience for complex assemblies
• Working knowledge of fluid components and ability to understand/develop fluid P&IDs for large-scale test systems
• Experience safely operating complex fluid systems, including high pressure gas, cryogenic fluids, flammables, and hydraulics
• Technical writing or documentation experience

Successful candidates must clear a background check administered by the US government to obtain clearance for on-site work at our government partner location in Stennis, Mississippi.

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:

$104,000—$156,000 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 [e-mail].