Senior Mechanical Design Engineer

  • 91370 Verrières-le-Buisson, France (PARIS)
  • International environment, Very good English, French is a plus
  • Space and Aviation manufacturing
  • Min 5 years of experience minimum
  • To be negociated

We are hiring for a company which is a pioneering space technology company specializing in advanced propulsion systems for small satellites. They are global experts in satellite propulsion, pushing the boundaries of streamlined in-orbit mobility for the rapidly expanding satellite constellation industry. Their clients across the US, Europe, and Asia trust us to design and deliver high-performance, precision-engineered propulsion systems that push technological boundaries while meeting demanding timelines and budgets. They made history in 2019 and 2020 with the world’s first in-orbit demonstrations of a unique state-of-the-art fueled electric propulsion systems. Today, they are experiencing rapid growth, with over 300 systems ordered to date.

We are seeking a Senior Mechanical Design Engineer to join our passionate and diverse team. In this role, you will be responsible for the mechanical design of advanced propulsion systems and their subcomponents, tackling complex challenges where structures and components must withstand extreme thermal, vibration, and shock environments.

As part of the Product Development Team, you are going to be at the intersection of cutting-edge research and mass production, transforming novel concepts into flight-ready systems that will shape the future of space propulsion. Joining us, you will be part of an international, collaborative, and creative team, that is passionate about developing our groundbreaking propulsion technology.

Main tasks and responsibilities:

  • Be responsible for the mechanical design of advanced propulsion systems and their subcomponents.
  • Work on challenging design problems in environments with extreme thermal, vibration, and shock conditions.
  • Bridge cutting-edge research and mass production to create flight-ready systems.
  • Work effectively in a fast-paced environment where priorities swiftly change.
  • Contribute to a highly collaborative team environment that emphasizes innovation and creative problem-solving.

Skills and qualifications:

  • Master’s degree in mechanical or aerospace engineering.
  • 5+ years of professional experience in mechanical engineering required.
  • Experience in DFM – Design for Manufacturing (CNC) 
  • Hands-on experience in Design, Build and Test prototypes
  • Extensive experience with CAD software (SolidWorks preferred but not required).
  • Experience in requirement-heavy industries is preferred (aviation, space, nuclear, automotive, etc.).
  • Fluency in English.

For more than ten years, I’ve been driven by one idea — the future of Space and Defense depends on the people behind it. My career began in technical recruitment, where I had the privilege to hire engineers designing cutting-edge systems for aerospace and advanced manufacturing.

Co-founding Demexios was a natural next step: a way to transform my industry knowledge and relationships into a dedicated structure that helps clients recruit faster, smarter, and with strategic alignment.
Over time, I built long-term partnerships with companies leading technological sovereignty — from NewSpace startups developing electric propulsion to defense integrators modernizing tactical and surveillance systems. These collaborations allowed me to form a powerful network of decision-makers, project leaders, and experts who now trust Demexios to deliver when precision truly matters.
Today, my role is not just to connect candidates and companies — it’s to ensure that every hire strengthens our clients projects.

Across the landscape of global security, Matthieu Konarzewski was forging his path in the defense sector. With a robust background collaborating with startups and international firms in software, health, fintech, and beyond, Matthieu honed his dual skills in technology and talent acquisition over several forging experience.

His story took a defining turn during a high-stakes engagement with defense contractors, where he specialized in sourcing profiles for mission-critical roles in ballistics, radar systems, and high-security embedded technologies. Imagine Matthieu navigating the complexities of international defense networks, identifying experts in GNC (Guidance, Navigation, and Control) and FPGA development to fortify teams against emerging threats. “I’ve learned how a talented team makes all the difference in achieving concrete results,” Matthieu shares, emphasizing his commitment to being a reliable partner in building resilient organizations.

His focus on defense profiles has led to seamless placements that enhance national security and industrial innovation, all while fostering long-term client relationships.