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Fall 2014 Vol. 14 Number 1

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A Pathway to Mars

The Red Planet May Be the Next Giant Leap for Mankind, But Getting There Will Require Numerous Challenging Steps

Two enduring questions have long dominated the minds of scientists and sci-fi enthusiasts alike: How far into space can humans go? And, what will we find when we get there? For now, given technological challenges and the limited ability of the human body to withstand long-duration space missions, Mars is the furthest realistic destination for human spaceflight.

The long voyage from Earth to Mars will be expensive, challenging, and dangerous. While maintaining a long-term focus on Mars as the "horizon goal" for human spaceflight, NASA should pursue a pathway approach that involves first reaching a series of intermediate destinations such as an asteroid, the moon, or Martian moons, according to a recent National Research Council report.

These intermediate stops will help incrementally build the technical capacity and knowledge required for a successful human visit to Mars. For each combination of destinations, there are trade-offs among affordability, schedule, risk, and frequency of missions, and the development of technologies or capabilities applicable to a future Mars mission. Ten high-priority capabilities need to be developed, the report says, with a particular emphasis on Mars entry, descent, and landing, radiation safety, and in-space propulsion and power.

While the report doesn't recommend which pathway NASA should follow, it says that extended surface operations on the moon would make significant contributions to a strategy ultimately aimed at landing people on Mars, and that it would also provide opportunities for international and commercial cooperation.

Rationale for Human Spaceflight. Public opinion of the space program has historically been positive, with views becoming more favorable after a significant accomplishment, such as putting a man on the moon in 1969. In the past, the rationales used to justify the cost and risk of human spaceflight have included economic benefits, national security, national stature and international relations, inspiration for science and engineering education, and contributions to scientific knowledge.

In today's budget environment, however, most of the public does not view spending for space exploration as a high priority. In fact, many people admit to not paying much attention to or being well-informed about the topic. Among the general public, and even among scientists in both space-related and unrelated fields, there is no agreement on a single pragmatic reason for continuing a human spaceflight program.

But a shared human destiny and urge to explore, as well as the eventual survival of the human species, provide aspirational rationales for space exploration. When supplemented by the practical benefits associated with the pragmatic rationales, there is an argument for a continued human space program in pursuit of the answers to those enduring questions.

A National Vision. The success of a human mission to Mars will rely greatly on a steadfast national commitment to the goal, one that doesn't waver across political administrations or economic scenarios. It will also benefit from international collaboration, including potentially with China, which has demonstrated its own methodical and successful progress toward a sustained human space program.

National leaders can use the report's set of proposed principles to decide on a given pathway, measure its progress, navigate off one pathway and onto another, or cease the endeavor altogether.

A pathway to Mars will be measured in decades and hundreds of billions of dollars, and will only succeed with appropriate funding. A flat budget, or one that increases only with inflation, will not work, the report states. The only pathways that would successfully land humans on the surface of Mars require spending to rise above inflation for an extended period.

-- Lauren Rugani

Pathways to Exploration: Rationales and Approaches for a U.S. Program of Human Space Exploration. Committee on Human Spaceflight, Aeronautics and Space Engineering Board and Space Studies Board, Division on Engineering and Physical Sciences; and Committee on National Statistics, Division of Behavioral and Social Sciences and Education (2014, 279 pp.; ISBN 978-0-309-30507-5; available from National Academies Press, tel. 1-800-624-6242; $67.00 plus $5.00 shipping for single copies).

The study was co-chaired by Jonathan Lunine, director of the Center for Radiophysics and Space Research at Cornell University in Ithaca, N.Y., and Mitchell E. Daniels Jr., former governor of Indiana and president of Purdue University in West Lafayette, Ind. The study was funded by NASA.

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