Senior Mechanical Engineer - TS/SCI Polygraph Required

Leidos; Reston (VA); On-site; USD 131,000 - 237,000; Full time

Job summary

Leidos in Reston, Virginia seeks an experienced Senior Mechanical Engineer to support national security missions by assessing, reverse engineering, and characterizing complex facilities in denied-access environments.

You will analyze layouts, model infrastructure, identify vulnerabilities, and deliver technical reports and CAD/BIM outputs for DoD stakeholders, collaborating with government and contractor teams.

Qualifications

• Active TS/SCI polygraph clearance and US citizenship.
• Bachelor's degree with 12+ years or Master's with 10+ years in relevant field.
• Experience in facility analysis, infrastructure vulnerability, and DoD/IC environments.
• Strong MEP knowledge across mechanical, electrical, and plumbing systems.
• Ability to assess HVAC equipment and system capacity via visual analysis.
• Experience interpreting drawings, layouts, and data from multiple sources.
• Proven judgment with incomplete information and clear communication.

Responsibilities

• Reverse engineering and characterize facilities in denied-access environments.
• Assess vulnerabilities, bottlenecks, and mission impacts.
• Create high-fidelity 3D models and run engineering simulations.
• Analyze supporting facility systems, focusing on MEP integration.
• Produce technical reports, CAD/BIM outputs, and simulations for DoD.
• Support R&D to advance methodologies and modeling capabilities.
• Act as subject matter expert within the technical domain.

Skills

TS/SCI clearance

Engineering principles

3D modeling

Data analysis

Decision making with incomplete data

Interdisciplinary collaboration

Education

Bachelor's degree +12y experience

Master's degree +10y experience

Tools

MEP systems design

CAD/BIM tools

3D modeling software

Job description

Senior Mechanical Engineer

Leidos is seeking an experienced Senior 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 leverage strong 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 an innovative engineer who can develop sound technical assessments in situations where complete information is inherently unavailable. The ideal candidate combines creativity, analytical rigor, and exceptional attention to detail with the ability to make informed decisions based on incomplete data. You will work alongside an interdisciplinary team of government and contractor professionals in a fast-paced, mission-focused environment while serving as a subject matter expert within your technical discipline.

Primary Responsibilities

• 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, providing engineering insight and technical guidance to support mission requirements.

Required Qualifications

• Candidates for consideration must possess an in-scope and active TS/SCI Polygraph clearance and the ability/willingness to maintain this clearance while holding this position. U.S. Citizenship is required.


• Demonstrated understanding of engineering principles, theories, and concepts and their application across a broad range of technical programs and mission challenges.


• Bachelor's degree with 12+ years of relevant experience, or a Master's degree with 10+ 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.

Preferred Qualifications

• 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 investigations, industrial accident analyses, or Department of Defense facility vulnerability studies.


• Professional Engineer (PE) license and/or Project Management Professional (PMP) certification.


• Experience identifying mechanical system vulnerabilities and developing effective mitigation or corrective action strategies.

#ASBA

#Snakehead

If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.

Original Posting

August 14, 2026
For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.

Pay Range

Pay Range $131,300.00 - $237,350.00
The Leidos pay range for this job level is a general guideline onlyand not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.

Pay And Benefits

Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement. More details are available at www.leidos.com/careers/pay-benefits.

Commitment to Non-Discrimination

All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.