Principal Systems Security Engineer; Onsite

At RTX, the world's largest aerospace and defense company, 185,000 great minds are united by purpose and inspired to make a difference solving the world’s most complex problems. With our three market leading businesses, world-class operations and investments in research and development, we offer capabilities and opportunity no one else can. Together, we push the boundaries of known science and find new ways to connect and protect our world.

Collins Aerospace is a leader in technologically advanced, intelligent solutions that help redefine the aerospace and defense industry. With a comprehensive portfolio and deep technical expertise, we help customers meet the demands of the global market. Join us and help shape the future of aerospace and defense.

Collins Aerospace is seeking a highly skilled Systems Security Engineer to strengthen and secure enterprise environments supporting Department of Defense (DoD) missions. The ideal candidate will bring deep expertise in Risk Management Framework (RMF) compliance, secure network architecture, operating system administration, and cybersecurity best practices. This role requires hands-on proficiency across Windows and Linux platforms, network infrastructure, and security control implementation, along with the ability to support accreditation activities and sustain mission‐critical systems.

The selected candidate will play a pivotal role in designing, securing, and optimizing infrastructure to ensure operational resilience, regulatory compliance, and performance excellence within a high‐security environment. This role will be worked onsite in Sterling, VA and requires an active and transferrable SECRET clearance. Relocation assistance is not available.

What You Will Do:

Develop, implement, and maintain secure system architectures and technical solutions that meet all DoD RMF requirements, with a focus on risk reduction, automation, and control effectiveness

Engineer, deploy, and harden enterprise network and system solutions to ensure high security, resilience, scalability, and performance across legacy and emerging infrastructures

Configure, secure, and maintain Windows and Linux environments using industry best practices, approved security baselines, and automated configuration management tools

Create, manage, and secure Infrastructure as Code (IaC) artifacts—such as Ansible and VMWare templates—to enable repeatable, auditable, and secure system provisioning

Design and optimize Ansible automation workflows to enforce configuration compliance, patch management, and secure baseline deployment across multi‐platform systems

Support RMF accreditation activities in collaboration with the Government ISSM, including documentation development, control implementation, assessment coordination, and continuous monitoring

Install, configure, and troubleshoot enterprise firewalls, routers, and switches to maintain secure network segmentation, traffic integrity, and a robust defensive security posture

Conduct structured hardware and software testing, vulnerability analysis, and security validation to ensure secure, reliable system functionality and compliance with security standards Qualifications You Must Have:

Typically requires a degree in Science, Technology, Engineering or Mathematics (STEM) and minimum 5 years prior relevant experience or an Advanced Degree in a related field and minimum 3 years of experience

Active and transferable U.S. government issued Secret security clearance is required prior to start date Linux or Windows experience

Experience with Active Directory, VMware, Administration, SIEM Tools (Splunk or Kiwi), backup and recovery software, Trellix Endpoint Security and Tenable Qualifications We Prefer:

Department of Defense Directive (DoDD) 8140 /…