In the quest for planetary exploration, Mars holds a special position in view of the many similarities it has with Earth. This article highlights the significant aspects of the concept design and planning which paved the way for the successful Indian Mars Orbiter Mission (MOM). Lessons learnt from historical failures of Mars missions are summarized. The main driving factors of the MOM design are reliability, optimal utilization of existing launch systems, and minimum energy orbit placement around Mars with an innovative, highly elliptic orbit.