The Exploration of Mars by Humans: Why Mars? Why Humans?

As we commemorate the 50th anniversary of Yuri Gagarin's historic flight in 1961, the first flight of a human in space, plans are underway for another historic human mission -- a human mission to Mars. Once we reach Mars, the human species will become the first two-planet species. Both the Bush Administration (in 2004) and the Obama Administration (in 2010) proposed a human mission to Mars as a national goal of the United States.


The reasons for a human mission to Mars are several and include, (1) The human urge to explore new and distant frontiers; (2) To inspire both the American public and the next generation of scientist, technologist, engineer and technologist (STEM); (3) Enhanced national prestige; (4) Technological leadership; (5) Enhanced national security; (6) The development of new technologies for non-space spin-off applications; (7) Enhanced economic vitality; and (8) New scientific discoveries not obtainable from robotic missions to Mars. Some have suggested other reasons for colonizing the Red Planet are more catastrophic in nature, including Mars as a safe haven for the survival of the human species in the event of an impact on Earth with a large asteroid or comet (remember the demise of the dinosaurs 65-million years ago as a result of an asteroid or comet impact). Some have even suggested that the colonization of Mars may be a possible solution to the exponential population explosion on our planet.

The human mission to Mars is a very exciting and challenging journey. The trip will take about nine months each way with a stay time on the surface of Mars of several hundred days. The long length of the mission will provide an excellent opportunity to engage the public and especially students in elementary and middle school in the mission. Following the launch of Sputnik 1 on October 4, 1957, the U.S. and the rest of the world witnessed a significant increase in the numbers of students studying science, technology, engineering and mathematics and entering the STEM professions (I was one of those students). In the U.S., the influx of students in the STEM professions resulted in new STEM-related products and industries, and in enhanced national security and enhanced economic vitality. Unfortunately, the situation has changed significantly in recent times with fewer students studying STEM areas and entering the STEM workforce. It is interesting to note that the new chief education officer at NASA, the associate administrator of education, is former Astronaut Leland Melvin, clearly an excellent role model for students.

Why Mars? One of the major questions in all of science is whether there is/was life outside of the Earth. After Earth, Mars is probably the most likely abode for life in the Solar System. Is there life on Mars today? Was there life on early Mars? If so, what is the structure and chemical composition of this life? Is it similar to life on our planet? Answering these questions is a very challenging task for robotic missions to Mars. Today, 35 years after the Viking landing on Mars, some life scientists are still debating the results and interpretation of the Viking life detection experiments. The discovery and analysis of life outside the Earth is a very challenging endeavor and requires the presence of human explorers/scientists for unambiguous results.

It is generally believed that Mars has experienced catastrophic climate change over its 4.6 billion year history. Scientists now think that early Mars was more hospital and more Earth-like than present-day Mars. Today, Mars has a very thin atmosphere with a surface pressure of only about six millibars, comparable to the pressure of the Earth's atmosphere at an altitude of about 100,000 feet (For comparison, the surface pressure of the Earth's atmosphere is 1,013 millibars). Early Mars most probably possessed an atmosphere considerably denser than its present-day atmosphere. The surface of present-day Mars is devoid of liquid water. However, photographs of Mars from orbit and from the surface suggest that early in its history Mars possessed abundant and widespread surface liquid water in the form of lakes, rivers and even planetary-scale oceans. What processes or mechanisms caused Mars to experience catastrophic climate change? How did Mars lose the bulk of its atmosphere? How did Mars lose its surface liquid water? Does climate change on Mars portend similar changes on our planet?

Why humans? Humans are unique scientific explorers and observers. Humans have unique capabilities for performing scientific measurements, observations and sample collecting. Human attributes needed for exploration and scientific discovery include: intelligence, adaptability, agility, dexterity, cognition, patience, problem solving in real-time, in situ analyses -- more science in less time. Humans can obtain previously unobtainable scientific measurements on the surface of Mars. Humans possess the abilities to adapt to new and unexpected situations in new and strange environments, they can make real-time decisions, have strong recognition abilities and are intelligent. Humans can perform detailed and precise measurements of the surface, subsurface and atmosphere while on the surface of Mars with state-of-the-art scientific equipment and instrumentation brought from Earth. The increased laboratory ability on Mars that humans offer would allow for dramatically more scientific return within the established sample return limits. The scientific exploration of Mars by humans would be performed as a synergistic partnership between humans and robotic probes, controlled by the human explorers on the surface of Mars. Robotic probes could explore terrains and features not suitable or too risky for human exploration. Under human control, robotic probes could traverse great distances from the human habitat covering distances/terrain too risky for human exploration and return rock and dust samples for analysis and interpretation to the habitat from great distances. The Apollo experience showed the great value of humans in the scientific exploration and discovery process on other worlds.

The unambiguous detection of life past and/or present on Mars and understanding the mechanisms/processes of climate change are best accomplished by human explorers/scientists on the surface of Mars. The human explorer/scientist can adapt to new and unexpected situations that Mars may provide. Robotic and human space exploration have come a long way in the last 50 years since the first human flight of Yuri Gagarin. However, the most exciting role for the human explorer/scientist is just beginning as we start the greatest adventure in human history, the human exploration of the Solar System starting with the Red Planet.

Author photo: NASA.

Presented by

Dr. Joel S. Levine is a senior research scientist in the Science Directorate of NASA's Langley Research Center. He is the principal investigator of the Langley-proposed Aerial Regional-scale Environmental Surveyor Mars Airplane Mission, a project searching for life on Mars.

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