“The United States has publicly funded its human spaceflight program on a continuous basis for more than a half-century, through three wars and a half-dozen recessions, from the early Mercury and Gemini suborbital and Earth orbital missions, to the lunar landings, and thence to the first reusable winged crewed spaceplane that the United States operated for three decades. Today the United States is the major partner in a massive orbital facility – the International Space Station – that is becoming the focal point for the first tentative steps in commercial cargo and crewed orbital space flights. And yet, the long-term future of human spaceflight beyond this project is unclear. Pronouncements by multiple presidents of bold new ventures by Americans to the Moon, to Mars, and to an asteroid in its native orbit, have not been matched by the same commitment that accompanied President Kennedy s now fabled 1961 speech-namely, the substantial increase in NASA funding needed to make it happen. Are we still committed to advancing human spaceflight? What should a long-term goal be, and what does the United States need to do to achieve it? Pathways to Exploration makes the case for advancing this endeavor, drawing on the history of human spaceflight to justify future programs in human space exploration. This report promotes the exploration of Mars as the horizon goal for the program. With this goal in mind, the report considers funding levels necessary to maintain a robust tempo of execution, current research and exploration projects and the time/resources needed to continue them, and international cooperation that could contribute to the achievement of spaceflight to Mars. According to Pathways to Exploration, it is not possible to meet the goal of human spaceflight to Mars without a sustained commitment to funding at a higher level than the space program is currently receiving.”