Dangers On Mars Require Extensive Evaluation Before Human Exploration Could Proceed

The agency's robotic engineering and design program should be expanded to develop larger rovers specifically for human use in exploration and surface transport, the report says. To ensure a safe landing and to aid rover and human movement on the planet, NASA should develop an accurate high-resolution, three-dimensional map of the terrain that would be explored, and assess the land's makeup to determine its strength and stability. In addition, when a spacecraft lands on Mars, soil and dust might be brought in through the air lock, which occurred during the Apollo missions to the moon. Potential contamination of the astronaut habitat while on the martian surface could pose a health hazard to the crew. For example, dust could contain high concentrations of sulfur and chlorine, compounds that could degrade human lung tissue if inhaled and corrode equipment.

There is also uncertainty as to the quantity of toxic metals, such as hexavalent chromium, in the soil. While small amounts of these metals may not affect the astronauts immediately, they could have long-term effects, such as cancer. Robotic sampling of soil and airborne dust could determine the presence and extent of any harmful organisms or compounds. If certain experiments, such as testing for chromium, cannot be conducted on the Mars surface, a sample must be returned to the Earth for evaluation.

Although chances are slim that life exists on the planet, NASA must identify zones of minimal biologic risk to humans through unmanned missions, using organic carbon detection techniques or by analyzing a sample returned to Earth. At the same time, NASA needs to implement a series of safeguards to protect the Earth from potential contamination when the missions return from space.

NASA and its international partners plan to send data-gathering robotic missions to Mars every two years until 2011 to study the environment, climate, and geology, and to determine if life ever arose on the planet.

This study was requested and funded by NASA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides science and technology advice under a congressional charter. A committee roster follows.

The report Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface is available on the Internet at http://www.nap.edu.