Internship Mechanical Engineer Defense Jobs (NOW HIRING)

Mechanical Engineer 

Parallel Systems is building autonomous, battery-electric rail vehicles to modernize freight transportation. We are seeking a Mechanical Engineer to help design and build the next generation of our vehicles. This is a hands-on role for an early-career engineer who wants to work on real hardware, solve practical mechanical problems, and stay close to the build. 

We are looking for people from top engineering programs who have already designed and built meaningful hardware through internships, Formula SAE, Baja SAE, Design/Build/Fly, rocket club, robotics, senior design, or similar technical programs. The right person is not just strong in theory, but knows how to turn ideas into physical parts, work through manufacturing constraints, and improve designs through testing and iteration. 

Responsibilities: 

• Design mechanical components, assemblies, and mechanisms for vehicle systems with a focus on performance, manufacturability, reliability, and integration. 
• Create and maintain CAD models, engineering drawings, and release packages for fabricated and purchased parts. 
• Own mechanical design problems from concept through build, test, and iteration. 
• Work closely with manufacturing, supply chain, test, and other engineering teams to move designs from CAD into hardware quickly and effectively. 
• Support prototype builds, fit checks, hardware bring-up, root cause investigations, and design revisions. 
• Participate in testing and validation of mechanical systems, review results, identify failure modes, and drive practical design improvements. 
• Perform engineering analysis as needed to support design decisions, including tolerance stack-ups, hand calculations, and other first-principles work. 
• Help troubleshoot mechanical issues on prototypes and vehicles, and contribute to fixes that improve robustness and field performance. 

What Success Looks Like: 

• Within 30 days: you have ramped on our vehicle architecture, tools, and engineering workflows, and are contributing to CAD work, design updates, and prototype support. 
• Within 60 days: you are independently owning straightforward mechanical parts and assemblies, producing release-ready drawings, and supporting those designs through fabrication and build. 
• Within 90 days: you are making meaningful contributions to vehicle hardware, helping solve real integration and reliability issues, and showing that you can move from design to build to iteration with a high level of ownership. 

Requirements: 

• Bachelor's degree in Mechanical Engineering or a related field. 
• 1 to 3 years of mechanical engineering experience through full-time work, internships, co-ops, or highly relevant project experience. 
• Strong CAD skills in SolidWorks, CATIA, Siemens NX, or similar. 
• Experience designing and manufacturing real mechanical hardware through internships, student teams, or personal technical projects. 
• Strong mechanical engineering fundamentals, including statics, dynamics, materials, tolerancing, and machine design. 
• Ability to create clear engineering drawings and communicate design intent effectively with machinists, fabricators, suppliers, and cross-functional teammates. 
• Comfort working in a fast-paced hardware environment where engineering decisions need to become physical hardware quickly. 
• Hands-on mindset with a willingness to spend significant time in the shop, lab, or build environment supporting hardware directly. 

Preferred Qualifications: 

• Leadership experience with Formula SAE, Baja SAE, Design/Build/Fly, rocket club, solar car, robotics, or similar hands-on engineering programs. 
• Experience designing parts for machining, sheet metal, weldments, composites, castings, or additive manufacturing. 
• Experience building and assembling mechanical systems, not just designing them. 
• Exposure to prototype development, design iteration, and debugging in a real hardware environment. 
• Familiarity with FEA, MATLAB, Python, or similar tools, with the judgment to use them in support of practical engineering decisions. 
• Interest in transportation, automotive, aerospace, robotics, or railway systems.