Mechanical Engineer

Leidos is seeking an experienced Mechanical Engineer to support critical national security missions in Reston, Virginia. This role focuses on the assessment, reverse engineering, and characterization of complex above-ground and subterranean facilities located in denied-access environments. The successful candidate will apply engineering expertise to analyze facility designs, spatial layouts, operational workflows, and supporting infrastructure to determine functional capabilities and mission relevance.

You will evaluate facility systems, model critical infrastructure, identify vulnerabilities, and provide technical insights that support complex intelligence and defense initiatives. This position requires a creative and analytical engineer who can develop sound technical assessments in situations where complete information is inherently unavailable. The ideal candidate combines strong problem-solving skills with engineering rigor, attention to detail, and a commitment to thorough analysis.

You will work alongside an interdisciplinary team of government and contractor professionals in a fast-paced, mission-focused environment supporting high-priority national security objectives.

• Reverse Engineering & Facility Characterization Analyze and characterize the physical and functional attributes of facility layouts, building architecture, and operational workflows within denied-access environments to determine facility purpose, capability, and operational capacity.
• Vulnerability Assessments Evaluate facility and infrastructure designs to identify security vulnerabilities, single points of failure, operational bottlenecks, and potential mission impacts.
• 3D Modeling & Simulation Develop high-fidelity 3D models and conduct engineering simulations to replicate facility operations, workflow efficiencies, and structural or mechanical limitations.
• Infrastructure Analysis Apply multidisciplinary engineering expertise to assess supporting facility systems, with a primary focus on Mechanical, Electrical, and Plumbing (MEP) integration and functionality.
• Technical Documentation & Reporting Translate field-collected data, intelligence information, and engineering assessments into comprehensive technical reports, CAD/BIM products, and simulation-based analyses for Department of Defense stakeholders.
• Research & Development Support customer-approved research and development initiatives independently or as part of a multidisciplinary team to advance analytical methodologies, modeling capabilities, and mission solutions.
• Subject Matter Expertise Serve as a subject matter expert within your technical domain area, providing engineering insight and support to mission-focused teams.

• Active and in-scope TS/SCI clearance and willingness to obtain a polygraph. Must be a U.S. Citizen.
• Demonstrated understanding of advanced engineering principles, theories, and concepts, and the ability to apply them across a broad range of technical programs and mission challenges.
• Bachelor's degree with 8+ years of relevant experience, or a Master's degree with 6+ years of relevant experience.
• Relevant experience includes facility analysis, infrastructure vulnerability assessments, and mechanical engineering within commercial, Department of Defense, or Intelligence Community environments.
• MEP Systems Expertise: Strong multidisciplinary understanding of Mechanical, Electrical, and Plumbing (MEP) system design, integration, and operational functionality within complex industrial or military facilities, including specialized containment systems, filtration systems, and backup power infrastructure.
• Ability to identify industrial HVAC equipment, estimate system size and capacity, and assess operational capabilities through visual analysis.
• Ability to evaluate, organize, and utilize large datasets from diverse sources, including field-collected data, equipment technical manuals, and existing facility models.
• Expertise in 3D modeling, engineering analysis, and physical simulation methodologies.
• Experience interpreting engineering drawings, facility layouts, blueprints, and intelligence-derived technical data.
• Demonstrated ability to make sound technical judgments with incomplete information while clearly communicating assumptions, uncertainties, and recommended paths forward.

• Five or more years of field experience working with industrial HVAC systems, including air-cooled and water-cooled chillers, condensers, cooling towers, air handlers, heat exchangers, boilers, and related equipment.
• Working knowledge of air management systems supporting critical environments, including medical laboratories, clean rooms, chemical laboratories, and similar specialized facilities.
• Hands‑on experience with advanced Building Information Modeling (BIM) and engineering simulation tools, including Autodesk Revit, VENTSIM, ETAP, and other industry-standard CAD and modeling platforms.
• Experience supporting forensic engineering…