These volumes provide a blueprint for manned missions to Mars and a continued presence on the planet’s surface, including what technology is required, and what kinds of precursor missions and experiments are required for this undertaking. Papers which do not appear in full are published as abstracts. These proceedings are based on updated papers which were originally presented at the fourth Case for Mars conference, “The International Exploration of Mars,” held June 4-8, 1990 in Boulder, Colorado.

Volume 89 (Mission Strategy and Architectures) is divided into three sections: Part I, making the international case for Mars, includes chapters on space policy and international cooperation/international science objectives; Part II, mission strategy, includes chapters on philosophy, planning, architectures, infrastructure and engineering; Part III, technical considerations for getting to Mars, includes chapters on robotic and precursor missions, transportation systems and spacecraft, and advanced propulsion. Numerical and author index included for both volumes.

Volume 90 (Considerations for Sending Humans) is divided into three sections: Part I, considerations for sending humans, includes chapters on communications and robotic versus human presence and radiation; Part II, living on Mars, includes chapters on in situ resource utilization, habitability and life support, and Mars base and infrastructure; Part III, social perspectives, discusses Mars habitability and analogs. Numerical and author index included for both volumes.