Mission Security Engineer

The role

You will own or contribute to the authorization posture of a space vehicle and a classified cloud mission operations environment. This role involves cyber engineering, producing RMF authorization documentation, and managing continuous monitoring.

What you will do

• Build and sustain authorization packages for both boundaries
• Get assessors engaged early on evidence-generation approach
• Own the POA&M
• Maintain the authorization system of record
• Own the authorization boundary determination for the flight segment
• Tailor the control baseline using Aerospace's Space Segment Cybersecurity Profile
• Define the type-authorization for the bus
• Derive verifiable security requirements from threat using SPARTA TTPs
• Define and document the authorization boundary for mission systems in classified cloud
• Implement controls as code

Required qualifications

• U.S. Citizenship
• Experience with technical tooling: reading pipeline output, querying an API, interpreting scanner and configuration state
• Bachelor's, master's, or PhD in systems engineering, computer science, cybersecurity, aerospace, or a related field
• Clear experience with hands-on building via coursework, internships, research code, personal projects, CTFs, a co-op, or an early role
• Exposure to RMF, security compliance, cloud, or software engineering
• Strong experience in embedded/space systems or cloud infrastructure
• Multiple systems taken to authorization in national security or DoD environments
• Fluency in RMF as practiced
• Direct experience with at least one accredited cloud environment and one non-traditional system

Nice to have

• Experience with OSCAL, eMASS APIs, Xacta, controls-as-code, or continuous-controls-monitoring implementation
• Skilled in Python, Go, or equivalent, in CI/CD, infrastructure-as-code, and Git-based workflows
• Experience with continuous authorization, ongoing authorization, or cATO
• Experience building with AI-assisted development
• Understanding of Mission Operations including satellite command and control, mission planning, flight dynamics, telemetry processing, or multi-mission ground segments
• Embedded or safety-critical background in space, automotive, or industrial control
• Experience with SPARTA, NIST IR 8270 or IR 8401, CCSDS security standards, Space Platform Overlay, NASA/Space Force system protection standards, or space-system threat modeling
• Experience with classified cloud accreditation at IL5/IL6 or IC equivalents, or accreditation under JSIG or ICD 703
• Qualified, or able to qualify, under DoDM 8140.03 for a systems security engineering, security architecture, or Information Systems Security Manager work role

Benefits

• Equity in Apex
• 100% company-paid medical, dental, and vision for you and your dependents
• $100k life insurance at no cost
• Starting at 15 days vacation, growing to 20+ days annually
• 10 paid holidays
• 100% match on first 3% of 401(k), 50% on next 2%
• 8 weeks paid parental leave
• Childcare reimbursement up to $350/day for work-related travel
• Daily catered lunch and unlimited snacks
• Monthly office socials, pickleball tournaments, run club, and gatherings

Before you apply

• U.S. Citizenship (must possess the ability to access export-controlled data)
• Active Top Secret clearance with SCI access and SAP eligibility strongly preferred

About the company

Apex manufactures satellite buses at scale using software, vertical integration, and hardware. They are a fast-growing startup that has raised more than $500M in funding.