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ISS eye test
A space station astronaut testing his vision, one of a growing number of medical concerns about spaceflight that could pose challenges to plans for human missions beyond Earth orbit. (credit: NASA)

A note on the possible impending death of human space exploration


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An invisible crisis is building in the area of human spaceflight with profound implications for human exploration of space. Human spaceflight is considered the embodiment of the space adventure for most states and individuals, the epitome of the human quest for what is over the next hill. For the United States, that vision structures much of what NASA does in searching for evidence of signs of life either in the solar system or the great beyond. However, whether human bodies can survive the experience of traveling great distances to visit other planets and other celestial bodies is becoming the great stumbling block. The more that is discovered about the hazards of space, the more problematic becomes the prospects for the long-term human survival in outer space.

That concern is masked currently by the reality that humans are not in space that long, and their return to Earth and normal gravity comes fairly quickly. In one important sense, the age of space exploration is not equivalent to the earlier age of European exploration of the world when ships and their crews embarked on multiyear voyages of discovery and conquest. It becomes more similar to the early Greek voyages of discovery within the Mediterranean Sea where the shoreline was usually just over the horizon. Star Trek-type voyages are obviously beyond humans’ current reach, but the reality may in fact be more brutal in limiting what can be done close to Earth.

The expectation

Our limited experience, plus our dreams, have created the expectation that humans will be able to visit other celestial bodies in the solar system (relatively) safely and, hopefully, work outward from there. In the most grandiose of these expectations, the human race will collectively flee to the other celestial bodies or to space habitats for long-term human survival, having destroyed or severely damaged the prospects for human life on Earth. These other worlds, usually including Mars, will become a lifeboat insuring the future of humankind. (Why such a desolate planet merits such a vision is itself a puzzle.)

The age of space exploration is not equivalent to the earlier age of European exploration of the world when ships and their crews embarked on multiyear voyages of discovery and conquest. It becomes more similar to the early Greek voyages of discovery within the Mediterranean Sea where the shoreline was usually just over the horizon.

Human prospectors will scour the solar system exploiting the resources found out there among the asteroids and other objects in space. One could harvest the water from comets after stripping the lunar craters of their ice. Using water from comets may be more problematic than once envisioned, but the idea is that water in some accessible form exists in the solar system and that can, in time, be provided for use in space operations or habitats. Arguing about how to supply future explorers or inhabitants of space is intriguing, but may be moot given the other apparent hazards of space.

What we know about the reality

Given our limited exposure, it has become clear that human bodies are compromised when exposed to the space environment for extended periods of time. It was always understood that special preparations had to occur if humans were to survive spaceflight. Those hazards include the intense temperature changes that occur, the effects of radiation that are often exacerbated by solar storms, and the deleterious impact of microgravity on human bodies. More recent medical observations have found significant deterioration in vision, which may be linked to the effects of microgravity on spinal fluid.

The Kelly brothers, both NASA astronauts and identical twins, were employed in an experiment in which one, Scott, flew to the ISS for a year while his brother, Mark, remained on Earth as a “control subject.” The twins will be studied in the coming years to assess the effects of space habitation on the two. Comparable experiments are obviously difficult to establish since experimentation on humans is a delicate matter at the best of times, so such “natural” experiments are likely to be the norm.

Ironically, expanding the future of space exploration may come from the ongoing development of enhanced autonomous vehicles for purposes of war.

When space habitats are established with the possibility for long duration habitation, the effects of space may become even clearer. But regardless, in the present context, space remains a hostile environment whose long term impacts are not truly understood. There have been discussions of one-way missions to Mars, although their ethical aspects could be problematic.

Alternatives become attractive

The quest to explore the solar system will continue, but the question is, how will that occur? Will humans lead the way or will it all be accomplished by machines? NASA’s effort, the Journey to Mars, assumes that machines will be the precursors exploring the environment and helping set up the basics while awaiting the arrival of human explorers. This building block approach assumes the humans can survive the realities of the long voyage to Mars and then work on the surface once they arrive. The NASA plan is for safe return of the explorers.

Alternative approaches assume that humans will live on the lunar surface first, for purposes of both research and proof of concept in terms of human habitation of a celestial body. Aritifical gravity, one potential solution to the problems of microgravity, has largely been dismissed is because of the difficulties inherent in spinning a spacecraft with people on board (see “The weak pull of artificial gravity”, The Space Review, October 31, 2016). Early visions of space stations, including Wernher von Braun’s iconic “wheel in space,” envisioned such arrangements in order to get gravity for the human crew. Roger Launius and Howard McCurdy have envisioned a different approach where humans become something more than human with artificial augmentation in order to survive the perils of the space environment (see “Review: Robots in Space”, The Space Review, February 18, 2008.)

All of the above approaches are based on the critical assumption that humans can survive long-duration space voyages. Failing that, the alternative becomes continued robotic missions. Ironically, expanding the future of space exploration may come from the ongoing development of enhanced autonomous vehicles for purposes of war. Defense budgeting is always more robust than civil space activities and even more so today with the heightened emphasis on commercialization of US space activities. The link between space and the military has been a long-standing relationship given that the original launch vehicles were usually derivatives of ballistic missiles developed for reasons other than space exploration.

The politics of human space exploration is infused with factors that prohibit rational employment of resources, including political fads, lack of real interest in space exploration, and simple impatience.

The use of drones have become a prominent feature in US security policy, but what is more important is their growing sophistication in terms of being able to operate autonomously for increasing periods of time. There is more money for those military developmental efforts than what’s available to NASA. Its rovers on the Martian surface are programmed to conduct their activities for specified periods of time before another set of commands is uploaded through the Deep Space Network. That means there is no opportunity for operator intervention as can occur during aerial operations on Earth: the distances are too great for such fine-grained control. Increasing the autonomy of the rovers and other robotic vehicles will be key to the future of space exploration, especially if the human presence remains limited. The central argument for humans being on site is their curiosity and ability to generalize off their observations to a non-logical but satisfactory conclusion that a robot cannot match. Improved autonomy could at least partially bridge that distance gap while the question of a long-term human presence in space is worked out.

NASA’s lack of interest in developing some form of useful artificial gravity for human passengers is puzzling, although it may reflect the reality of budgets and other constraints. The politics of human space exploration is infused with factors that prohibit rational employment of resources, including political fads, lack of real interest in space exploration, and simple impatience. Building a long-term human space exploration effort needs to emphasize the long-term aspect.

A new presidential administration is rolling into Washington with unknown effects for NASA and its programs. Does a restructuring occur again or do we simply make a detour to the Moon on the way to Mars? The unknown is whether humans will be on that mission. American space exploration to this point has not been a series of suicide missions; rather, the point is to get there and back safely, barring the unforeseen of accidents not the normal harsh realities of the space environment. Ironically, the fate of human space exploration may not be in funding and the technology to get there but the reality of human survival in space. I would hope I am wrong but these realities must be faced.


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