This volume comprises the select peer-reviewed proceedings of the 8th International Conference on Product Lifecycle Modeling, Simulation, and Synthesis (PMLSS 2021), jointly organized by the Vikram Sarabhai Space Centre (VSSC) and Indian Institute of Space Science and Technology (IIST)  in collaboration with PLMSS Trust, Bangalore, India.  It aims to provide a broad spectrum picture of the state-of-the-art research and development in the areas of additive manufacturing, aerodynamics, mission design, modeling & simulations, AI/ML/Industry 4.0/CAD/CAM/CAE, space system design, materials, and manufacturing process development and simulations, PLM - aerospace & aircraft applications. PLMSS-2021 served as a platform to exchange ideas and information about the latest PLM practices to achieve product excellence and improve yield. The intention of the conference was to unify R & D institutes, academia and industry to discuss over novel methods, challenges and possibilities in PLM in the space system perspective. This volume will provide a valuable resource for those in academia and industry.