Construction Mechanical Engineer II

Location: Long Beach, California, United States

Department: Construction Design and Delivery

About the Team: 

The Construction Design and Delivery team is at the core of Relativity's growth and development. Through our collaboration and expertise, we deliver projects that lay the foundation for Relativity's future success. In essence, we build the factory that builds the rockets! We are responsible for cross functional relationships with reams such as Manufacturing, Propulsion, PBF, Avionics, Machine Shop, Facilities, EHS, and Security to name a few, working through design specification and execution of critical infrastructure projects that supports the mission of work centers. Our relationships don't stop there, working daily with government agencies, utility suppliers, vendors and contractors who support our factory build out. Our team ensures that all projects meet operational requirements, safety and environmental codes, all the while remaining within budget, delivering on time, and to the highest quality as we help to drive production forward. 

About the Role: 

• Support the design and development of mechanical systems, including HVAC, plumbing, process gas distribution, and specialized systems such as cryogenic, high-pressure, and oxygen monitoring systems.
• Perform engineering calculations, equipment sizing, load analyses, and system performance evaluations to support efficient, reliable, and code-compliant mechanical designs.
• Develop and maintain mechanical design documentation, including AutoCAD drawings, Revit models, Basis of Design narratives, technical specifications, and as-built drawings.
• Collaborate with cross-functional engineering, construction, manufacturing, and facilities teams to ensure mechanical systems are properly coordinated, constructible, and aligned with operational requirements.
• Support mechanical and plumbing projects from initial concept and design through construction, commissioning, and final handoff, including scheduling, budgeting, risk assessment, and documentation.
• Review designs, drawings, and submittals from external consultants and vendors to ensure compliance with applicable codes, industry standards, project specifications, and safety requirements.
• Conduct site inspections, troubleshoot technical issues, respond to RFIs, and coordinate with contractors and internal stakeholders to resolve field challenges and maintain project timelines.
• Support system startup, testing, commissioning, and continuous improvement initiatives to enhance the efficiency, reliability, and maintainability of manufacturing and office facilities.

About You:

• Bachelor of Science degree in Mechanical Engineering or a related engineering field.
• Minimum 2+ years of experience in mechanical design and engineering for infrastructure, manufacturing, or commercial building systems.
• Experience in the design and specification of HVAC, hydronic/chilled water, plumbing, drainage, compressed air, and exhaust systems.
• Experience developing Basis of Design (BOD) documentation, mechanical load calculations, and equipment sizing.
• Familiarity with mechanical codes and standards, including ASHRAE, Title 24, NFPA, and Uniform Plumbing Code (UPC).
• Experience in creating and reviewing permit-ready mechanical drawings and specifications.

Nice to have but not Required:

• Master’s degree in Mechanical Engineering or related field.
• Engineer In Training (EIT) Certification.
• LEED GA or LEED AP accreditation.
• Background in supporting cleanroom ventilation, specialty gas systems, or critical environment design.