To the Presidential Commission on Moon, Mars and Beyond, Dr. Marianne Frey, Professor Emeritus School of Aerospace Medicine, Wright State University, presented her views about the challenges to long-duration human exploration of the moon and Mars
Our vision to send men and women to the moon and Mars can be an inspiration and a unifier for the people of the United States of America and for the world. However, exploration has risks. And ethically before these brave pioneers embark, we must be able to minimize their risks. And maximize their well-being, their ability to perform successfully in space, and their chances to return to a normal life on earth.
|Artist's conception of an early, pre-terraforming outpost for human visitors to Mars. Painting by Mark Dowman. Credit: Dowman/JSC/NASA.
The risks come from at least four sources. First, the reduced gravity environment. From almost zero to about 1/3 earth's gravity, which will cause fluid shifts in the body, loss of normal stress on the bones and muscles, and changes in stimuli to the nervous system.
Second, the environment inside the vehicle or habitat poses threats from floating particles, which might be inspired. Toxic wastes, poor illumination, loud noise and poor thermal control.
Third, the environment outside the vehicle or habitat poses threats, including radiation and meteorites or other debris.
And fourth, the psychological and psychosocial stresses will be extreme.
Two risk factors that will rise to major importance for long distance, long-duration journeys are, first, the psychological and psychosocial challenges of these missions will be huge.
Crewmembers will be isolated at great distances from earth with long lag times in communication. They'll be crowded into close quarters they will be in danger. And their sleep will be degraded. Interpersonal and group dynamics for intercultural and intergender groups must be understood and appropriate countermeasures developed.
The cosmic and solar radiation encountered outside of earth's protective magnetic field is unlike anything that we have here on earth. We must learn more about this radiation, about its effects on humans, including cancers and genetic problems and cataracts and how to provide effective shielding and other protective countermeasures.
|Thin atmospheric layer above cratered terrain. Credit: JPL/NASA.
Other risks of space flight, which were concerned in the short-duration missions of the past and the present will be much greater threats in the exploratory missions of the future.
First the loss of bone mineral in space flight. About 1% per month. That's 10 times what people lose as they're aging.
Cardiovascular changes, including arrhythmias and loss of exercise capacity and tendency to faint when hitting gravity on the moon, Mars, or on Earth. Muscle and strength loss. Neurological changes, including spatial disorientation, space motion sickness and neuromuscular changes.
The immune system's reduced effectiveness in space and allergic responses. Inadequate nutrition and food supply. And the requirement for extensive extra vehicular activity, including risk of decompression sickness.
A related daunting challenge that is critical to astronaut health on a mission to Mars is the necessity for advanced life support capability. This includes a closed system for oxygen, water and food. And effective waste management system. Accurate environmental monitoring, and user-friendly space suits and gloves to protect the astronauts and to Enable them to do protective work and to do productive work on the surface of the moon and on mars.
I've not addressed the very important challenge of providing medical care on exploration missions. Potential countermeasures include exercise programs, both aerobic and resistive. Pharmacological interventions, nutrition and diet, light. Human factors design. Psychological testing and interventions. Selection criteria, including genetic screening and training. And probably a short-arm human centrifuge to provide artificial gravity.
|"We can use the International Space Station or a dedicated space station as an isolation laboratory in which to study samples returned from other worlds, without fear of contaminating the Earth." -Ben Bova
Image Credit: NASA
The platforms for research and testing to allow us to meet these challenges will include the following. The international space station will be of major importance for testing countermeasures and for some of the research required to understand the threats and to develop countermeasures. However, the ISS will not be a useful platform unless it has a crew of at least seven, allowing at least four to five crewmembers to be researchers and subjects. It must also have a necessary laboratory facilities.
The moon could be a valuable laboratory for some research, and for some countermeasure testing for Mars. Knowledge can be gained in living in less than one g [gravity] environment the effects of transitions between g levels and radiation.
And finally appropriate analogs on earth, such as human studies in bed rest or in the Antarctic, and animal research to learn about mechanisms of some of the medical and physiological stresses.
A much greater level of commitment and of funding for biomedical research and countermeasure research and development must be made than has ever existed before.
After all, we're talking about sending people to Mars, human beings to Mars.
Related Web Pages
Future Exploration Missions
Human Exploration and Development of Space
NASA Human Spaceflight: Exploring Mars and Beyond
Tyson Testimony to Congress on Astrobiology
Best Laid Plans, Men and Machines