The paper describes the results of the efforts carried out in Europe for the definition, design and development of an EVA Suit Enclosure Module (ESEM) operating at 500 hPa, within the frame of the development studies for the Hermes Spaceplane EVA System. The assessment of the main performance requirements of the ESEM has been supported by the results of previous EVA System Studies and by experimental activities. These activities included: tests with an ergonomic test bench for the definition of the entry concept and the main geometrical parameters of the Hard Upper Torso (HUT), soft materials thermal and mechanical characteristics evaluation, preliminary components tests. Following the results of the experimentation and knowing the lessons learned from the OS and USSR EVA experience, a preliminary design concept for the future ESEM was established. The main features of such concept are; hybrid suit (HUT and soft limbs) with rear entry, a lower torso with hip and thigh bearings, rolling convolute joints for the shoulder articulations.