Senior Battery Systems Engineer

About the Team: 
The Avionics team is responsible for the full lifecycle of Terran R's nervous system — designing, building, testing, installing, and operating the hardware that connects and controls every major electrical system on the vehicle and ground. Engineers are deeply embedded into other functions within Relativity, working closely with propulsion, GNC, fluids, and stage engineering teams to ensure seamless integration and operation. As a Staff Engineer, you'll help shape Terran R's fundamental avionics architecture, own critical flight hardware, and build and grow the team that delivers it.
About the Role:
You will join the team developing the vehicle's high-voltage battery system and grow into technical ownership of it as a complete product, covering cell, mechanical, thermal, electrical/BMS, and vehicle integration. Early on, you will work closely with experienced battery engineers to learn the current design, its history, and how it flies. Over time, you will take on more of the system's technical direction. You will be the link between the battery's mechanical and electrical disciplines and the rest of the vehicle. You'll help turn mission and vehicle needs into a clear, traceable battery specification, and help shape the architecture that meets it. This is a hands-on technical role with real cross-functional influence. As the battery team grows, it offers a clear path to technical leadership, including leading other engineers.
Architecture & Requirements

• Partner with the vehicle and power-system architecture team to define battery requirements from the top down — deriving energy, power, voltage, thermal, mass/volume, and life requirements from mission profile, ConOps, and power-system needs rather than anchoring on legacy designs
• Own and maintain the battery specification — the single source of truth for battery requirements, interfaces, and verification criteria — with full traceability
• Drive battery architecture and cell down-selection through documented trade studies (requirement driver → options → evaluation criteria → rationale → recommendation), in collaboration with the battery mechanical, test, and BMS engineers
• Define and manage interface control (electrical, mechanical, thermal, data) between the battery and the vehicle

Cross-Functional Definition

• Work with Flight Sciences, ConOps, and the Criteria team to define the battery's environmental and loads requirements — launch and flight vibration/shock, thermal environments, thermal cycling, EMI/EMC, altitude/vacuum, and mission duty cycles
• Partner with the avionics/EE team to define BMS requirements and scope — cell monitoring, balancing, protection (OVP/UVP/OCP), contactor/heater control, state estimation, and fault management
• Coordinate with the mechanical and vehicle-integration teams on packaging, mounting, thermal management, and installation interfaces
• Work with the criteria and structures teams to close structural, thermal, and safety margins

Safety & Verification

• Own battery safety architecture — thermal-runaway detection and propagation mitigation, venting/burst-disc strategy, physical cell protection, and hazard analysis
• Define the verification and qualification strategy — qualification and acceptance test programs at cell and pack level, test-as-you-fly philosophy, and the data systems that turn test results into rapid design feedback
• Lead FMEA/FTA, reliability analysis, and identification/mitigation of single points of failure

Program & Technical Leadership

• Carry technical program-management responsibility for the battery effort — schedule, risk, dependencies, and status — and serve as the organized, single point of communication for battery status across teams
• Represent the battery at vehicle design reviews (PDR/CDR-class), safety review boards, and cross-functional forums
• Support supplier and cell-vendor engagement, including benchmarking, RFI/RFQ evaluation, and technical down-selection
• Contribute to producibility/DFM and NPI as the design matures, and lead structured root-cause and corrective-action (RCCA) for anomalies

About You:

• Bachelor's degree in engineering (mechanical, electrical, aerospace, chemical, or related)
• 5+ years of battery systems development experience across the product lifecycle (concept → design → qualification), including HV lithium-ion packs
• Demonstrated ability to derive and own requirements top-down, with rigorous trade studies and traceable specifications — not just execute a fixed design
• Working depth across the battery stack: cell selection/characterization, pack architecture, thermal management, BMS scope, and safety/abuse behavior
• Strong understanding of battery safety, failure modes, and HV system fundamentals
• Proven cross-functional leadership and clear technical communication in fast-paced development environments

Nice to haves, but not required:

• Experience in aerospace, launch vehicle, automotive HV, or another high-consequence, environment-driven domain
• Familiarity with environmental qualification (vibration, shock, thermal-vacuum, EMI/EMC) and test-as-you-fly verification
• Functional safety / hazard analysis background (e.g., FMEA, FTA, ISO 26262 or aerospace equivalents)
• Experience with requirements and modeling tools (DOORS, Jama, Cameo/MBSE)
• Hands-on cell characterization and abuse/destructive test experience
• Familiarity with charging/ground support equipment and ground operations