The present work delves into the mechanical design and analysis aspects of digital electronic systems with multi-pin integrated circuits mounted on multi-layer PCB’s which brings challenges in terms of design for their mechanical integrity and efficient thermal management. The paper focuses on Computer-Aided Design (CAD) modelling approach and Finite Element Method (FEM) based simulation aiming to create a robust system capable of withstanding diverse environmental conditions. By leveraging simple FEM techniques, design cycle of an electronic system can be reduced as compared to prototyping in which one design iteration can take hundreds of working hours. Our work contributes to the evolving landscape by providing a systematic approach and evolving effective strategies for creating reliable mechanical packages for ensuring high performance of digital electronic systems in the intended harsh space environment. Final design also corroborates the selection of Column Grid array devices as compared to Ball Grid array devices for space use.