The Dynamics of Human Spaceflight Systems – Part I
By Dr. Gary L. Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
The first article in a five-part series on the dynamics of human spaceflight systems for interplanetary and deep space missions.
In his seminal television series Cosmos, the late Dr. Carl Sagan drew a comparison between the Atlantic Ocean that stood in the way of explorers such as Columbus centuries ago and the limits of outer space as we came to know them in the 20th century. Sagan, who died in 1996, analogized space as a kind of “cosmic ocean” that stood between us and our conquest of space; he asserted confidently that space is “no more impassable than the [Atlantic].”
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And he was correct. The challenges to space travel are certainly daunting, but they can be understood and predicted through the laws of nature. Therefore, they are by no means outside the reach of human ingenuity. But looking at the amount of progress our species has made in exploring space since our first attempts in the mid-20th century, one might understandably begin to question that statement. Yet the biggest problems of space exploration have never been physical challenges that we’ve been unable to solve, but rather funding and support from the general public that we’ve been unable to cultivate.
Assuming that we find a means in the future to generate such support, we might begin to think about what our first interplanetary voyages would look like. There is one thing of which we can be certain: The types of spacecraft that we use to make these trips will be vastly unlike anything we’ve ever seen before.
Exponentially Larger Space Missions Will Need to Be Tackled by Giant Space Stations
Rather than small space ships that we’ve used for launching astronauts into Earth orbit or to the Moon, these exponentially larger missions will need to be tackled by giant space stations with extremely well-thought-out systems and equipment to transport humans safely and comfortably to and from their exploration targets.
One of the biggest considerations in spacecraft design is size. Typically, costs are more or less directly related to size, with bigger spacecraft costing significantly more money. And given that space exploration is already absurdly expensive — an average of $10,000 per pound to launch into space — this is not a variable that engineers can afford to ignore.
But trips to our nearest potentially habitable neighbors Venus and Mars will take three to six months one way using today’s latest space propulsion technologies. And the outer planets and moons are orders of magnitude farther away. So all human passengers aboard will need to have sufficient space to maintain not only their physical health and hygiene, but also their psychological stability.
The ISS Does Not Have Anywhere near the Facilities Necessary for Interplanetary Trips
The International Space Station (ISS) carries six crew members and has a habitable volume of a little less than 13,700 cubic feet. But most of that space is allocated to airlocks, storage, science experiments and equipment, or other necessary priorities. The ISS does not provide anywhere near the kind of physical support facilities and space necessary for interplanetary trips.
At a bare minimum, crew members on such trips will need sleeping quarters, eating areas, and hygiene facilities. Additionally, psychological research has conclusively demonstrated that socialization, exercise, recreation, and accommodations for privacy are all necessary components of a healthy human psyche. So these spaces will need to be designed into interplanetary space stations. A 2015 NASA study report recommended a minimum allocation of 883 cubic feet per crew member for long-duration space missions of up to two and a half years.
This amount of space and facilities, multiplied by the number of crew members needed for such missions, would suggest a space station of enormous size and cost. However, some space industry pioneers, such as Bigelow Aerospace, have been researching the ability to design and launch larger spacecraft in smaller, more affordable packages.
Bigelow has specifically been experimenting with inflatable habitat modules that are lightweight and can be folded into very small forms for launch. Then, once in orbit, they can be inflated and pressurized for crew occupation. However, inflatable space habitats come with their own set of concerns and drawbacks, which will be discussed in later parts of this series.
In part II, we’ll look at the need for gravity aboard manned spacecraft, and how we might go about achieving artificial gravity in deep space.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.