The human race has evolved, grown and expanded through the exploration of Earth. After initial steps on the Moon, our next challenge is to explore the solar system. Mars shows potential for both scientific discovery and future human settlement, and so is a prime candidate for the next leap of human exploration. Such a bold endeavor will be a driver for an unprecedented worldwide cooperative effort and the catalyst for a new era of international, intercultural and interdisciplinary human relations. Scientific and technological progress will also accelerate as mankind is ushered into a new era of space exploration.

Currently proposed Mars missions have identified a number of challenges such as high levels of radiation, harsh climate and limited launch windows. Recently discovered lava tubes on Mars present potential solutions to some of these issues, but raise a variety of intriguing new challenges. These encompass not only technological and engineering considerations, but also legal, ethical and societal issues such as planetary protection and crew safety. This report assesses the feasibility of overcoming such challenges through the exploitation of Mars caves.

This report reviews existing reference missions and identifies areas of further research essential for adapting mission architectures to utilize caves. Cave suitability is considered with respect to size, type, location and their potential to mitigate hazards. They are also assessed with respect to their potential for scientific work adhering to astrobiology guidelines and the search for extra-terrestrial life. This report compares surface and subsurface habitat options. Engineering challenges arising from the use of caves are addressed along with proposals for alternate architecture solutions. Mission analysis is conducted to determine the transit trajectory and define two possible mission scenarios with surface crews of 6 and 12 crew members. Different types of habitat are described and evaluated. An architecture for precursor missions is provided utilizing surface rovers, cargo delivery rovers and pressurized human transport vehicles. The implications of sub-surface operations on thermal control, communications and power systems are investigated with recommendations given. Crew selection, training methods and life support system solutions are also addressed.

Literature suggests a low radiation environment within Martian caves, allowing for extended duration missions. The ACCESS Mars Team concludes that using lava tubes as human habitats is not merely a viable habitat solution for a Mars expedition, but also potentially more beneficial than proposed surface solutions.