The International Mars Exploration Working Group (IMEWG) is a forum for space agencies and institutions to exchange ideas and information and discuss common strategy and initiatives for exploration of the planet Mars. The working group meets several times per year. Conceived in 1993, IMEWG's goal is to keep all parties informed and thereby avoid duplication of effort, and to discuss potential areas for collaboration/cooperation during the various phases of exploration. Founding participants included NASA, ESA, several European national agencies and those of Japan and Russia. IMEWG was initially chartered with the following goals: The first IMEWG recommendations on an international strategy for Mars exploration, covering launch opportunities from 1996 to 2003, included an International Mars Network. The recommendations were presented at the COSPAR Symposium in Hamburg, 1994, and published. The charter was updated in 1996 with the following goals: IMEWG meetings have also afforded an opportunity to reflect on the implications of mission losses for future programmes (e.g. in 2000). Later IMEWG initiatives have covered themes such as exobiology, planetary protection, Mars Sample Return, lower cost missions, common standards and interoperability (e.g. for data relay), radioisotope power systems, terrestrial Mars analogues, and preparations for future human exploration. The international Mars Architecture for the Return of Samples (iMARS) Working Group was chartered by IMEWG in mid-2006 to develop a potential plan for an internationally sponsored and executed Mars sample return (MSR) mission. An iMARS Phase 2 Working Group was constituted in 2014 for drafting a Mission Architecture and Science Management Plan for the return of samples from Mars. In 2024 the IMEWG Terms of Reference were updated once more, with the objectives reformulated as follows:

Agencies Represented