Space Vehicle Systems Engineer

About the company

Apex is a space startup that manufactures satellite buses and is involved in missile defense collaborations.

About this role

Spacecraft represent the most pressing unmet need across the entire aerospace industry. As more launch vehicles come online and the cost to orbit decreases, more companies launching payloads to space continue to emerge. For the first time in history, this influx of payload companies combined with reduced launch costs has resulted in a massive increase in need for commercial spacecraft platforms, known as satellite buses. These buses hold the payloads of our customers and are flown on launch vehicles. Apex manufactures these satellite buses at scale using a combination of software, vertical integration, and hardware that is designed for manufacturing. Our spacecraft enable the future of society: ranging from earth observation to communications and more. We’d love for you to join us on our mission of providing humankind access to the galaxy beyond our planet.  ABOUT THE ROLE Apex is looking for a Space Vehicle Systems Engineer to support system-level design, integration, and verification over the lifecycle of commercial and government programs. In this role you'll define space vehicle architecture from mission objectives, allocate and trace requirements down to the subsystem level, and hold the interfaces together so that every element operates as one coherent vehicle. Because our work supports national security missions, you'll also serve as a technical anchor between internal engineering teams, government customers, and external payload partners—translating requirements, presenting at design reviews, and driving disciplined execution against program milestones. This is a broad, hands-on systems role for an engineer who's comfortable moving fluidly between deep technical analysis, cross-disciplinary coordination, and customer-facing communication. Responsibilities: - Define and manage spacecraft-level and space vehicle architecture and requirements derived from mission goals, maintaining traceability across the full lifecycle. - Lead system-level trade studies, risk analyses, and simulations to guide design decisions across competing performance, cost, and schedule constraints. - Own the development and upkeep of system documentation, including specifications, Interface Control Documents (ICDs) between bus and payload, and technical budgets. - Coordinate subsystem integration and enforce interface compatibility across electrical, mechanical, thermal, and software domains. - Analyze test and integration data, isolate anomalies, and drive resolution alongside subsystem and verification teams. - Identify and assess technical risks, develop mitigation plans, and track them to closure; support FMEA and broader reliability efforts. - Support and present at major program and design reviews (e.g., SRR, PDR, CDR, TRR), ensuring technical readiness and compliance. - Align technical activities to program schedules and milestones, and advise program leadership on cost-driving technical decisions. - Engage directly with government customers and partners to capture requirements, resolve technical issues, and represent Apex in reviews and status updates. - Communicate complex technical concepts clearly to both engineering and non-technical audiences. - Contribute lessons learned and standardized practices that improve execution on future missions. Requirements: - Active Top Secret or Top Secret/SCI clearance required; ability to obtain and maintain access to additional programs as needed. - Bachelor's degree in Aerospace Engineering, Electrical Engineering, Mechanical Engineering, Physics, or a related field; advanced degree is a plus. - 5+ years of systems engineering experience, preferably in spacecraft, aerospace, or defense hardware development. - Strong grounding in systems engineering principles, requirements management, and verification and validation methodologies. - Working knowledge of spacecraft subsystems and their interdependencies, including attitude control, power, thermal, propulsion, communications, and command and data handling. - Proficiency in requirements management tools and systems engineering software (e.g., DOORS, Jira, SysML). - Knowledge of industry standards and best practices, such as INCOSE standards and NASA systems engineering guidelines. - Experience with mission analysis or modeling tools such as Python, MATLAB, STK, GMAT, or FreeFlyer is a plus. - Familiarity with space communications protocols and standards (e.g., CCSDS, S-band, X-band) is a plus. - Prior experience supporting government customers, prime contractors, or DoD program reviews strongly preferred. - Strong analytical and problem-solving skills with a high attention to detail. - Excellent communication and interpersonal skills, with the ability to work independently and juggle priorities in a fast-paced environment. #LI-HC1 WHY JOIN APEX? Apex believes in creating a work environment that you look forward to embracing every day. Our employees love working at Apex, and we want you to love it too. We're a fast-growing startup that has raised more than $500M in funding, and we invest heavily in our people from day one. WHAT WE OFFER FOR FULL-TIME EMPLOYEES: - Shared upside: Receive equity in Apex, letting you benefit from the work you create - Best-in-class healthcare: 100% company-paid medical, dental, and vision for you and your dependents, plus $100k life insurance at no cost - Comprehensive PTO package to reset and recharge - starting at 15 days vacation, growing to 20+ days annually, plus 10 paid holidays - Competitive 401(k) plan with generous matching - 100% match on first 3%, 50% on next 2% - 8 weeks paid parental leave plus childcare reimbursement up to $350/day for work-related travel - Daily catered lunch and unlimited snacks to keep you fueled throughout the day - Vibrant community: Monthly office socials, pickleball tournaments, run club, and gatherings for you and your family - Your dream desk setup and all the