Systems Engineer III Security Clearance

Position: Systems Engineer III with Security Clearance
Celeris Systems is seeking a Systems Engineer III to join our Systems Engineering and Integration team supporting U.S. Space Force Space Systems Command programs in El Segundo, CA. This position will support classified analysis, model-based systems engineering, requirements verification, and technical assessments for space, ground, user, and RF receiver systems. The ideal candidate has a systems engineering background with strong analytical skills, experience working in classified DoD environments, and the ability to evaluate RF receiver performance, signal characteristics, signal-to-noise ratio, uplink/downlink concepts, threat-based environments, and jamming effects.

The candidate should be comfortable working with engineering data, requirements, models, and mission/system performance information to support government decision-making.

Key Responsibilities

• Support classified technical analysis for DoD space, ground, user, and RF receiver systems.
• Analyze RF receiver performance, including power levels, signal-to-noise ratio, link performance, interference, and jamming effects.
• Support mission, threat, and system performance assessments using engineering data, test results, models, and operational scenarios.
• Use model-based systems engineering tools and digital engineering environments such as Cameo, SysML, KNIME, DOORS, DOORS Next, Jira, and iRIS to support system analysis and requirements traceability.
• Develop, maintain, and analyze system models, requirements, verification data, and technical artifacts.
• Support geospatial and positional analysis, including mapping system or asset positions, operational areas, coverage considerations, and scenario-based performance impacts.
• Lead or support Modeling and Simulation Verification, Validation, and Accreditation activities for satellite simulators, control system simulators, RF receivers, and related mission systems.
• Develop M&S VV&A plans, reports, and supporting documentation in alignment with applicable DoD guidance.
• Support test planning and execution for end-to-end system performance, with emphasis on RF receiver behavior in threat-based or contested environments.
• Perform data analysis, develop technical findings, prepare test reports, and verify system and receiver-level requirements.
• Track test articles, manage deficiency reports, and support corrective action tracking.
• Manage, update, and maintain requirements within DOORS, DOORS Next, iRIS, or similar requirements databases.
• Support acquisition, integration, sustainment, and technical risk assessment activities for space, ground, and user segments.
• Maintain program metrics including requirements burndown charts, verification status, risk items, and Test and Verification Events Matrix data.
• Interface with government customers, program leadership, analysts, engineers, and technical stakeholders in classified and unclassified environments. Position Characteristics

• Demonstrates strong analytical judgment and the ability to assess complex technical data in support of classified mission and system analysis.
• Understands RF signal characteristics, signal-in-space concepts, uplink/downlink performance, receiver sensitivity, signal-to-noise ratio, power levels, interference, and jamming effects.
• Applies systems engineering and model-based systems engineering principles to evaluate requirements, architectures, interfaces, verification data, and system performance.
• Works independently in a classified environment under general direction.
• Develops solutions to complex engineering and analytical problems requiring evaluation of multiple technical, operational, and programmatic factors.
• Communicates technical findings clearly to government customers, program leadership, engineers, and analysts.
• Exercises sound judgment when interpreting incomplete data, identifying risks, and recommending mitigation approaches.

Required Qualifications

• Bachelor’s degree in Engineering, Science, Mathematics, Physics, Data Analytics, Operations Research, or related technical field.
• 5+ years of experience supporting DoD, space, satellite, RF, missile, sensor, intelligence,…