Frontiers are meant to be explored, and space—it is said—is the final frontier. In many ways, the exploration and long-term settlement of our solar system will be entirely different from the European colonization of the Americas or the later western expansion of the United States. The extreme environment of space, the vast distances, lack of indigenous resources, and the mere act of leaving Earth’s surface will present challenges unique to our “star-ward” journeys.
Despite these new complications, we can still look back to America’s westward expansion of the 1800s to find some ideas that might help our next generation of explorers. For example, yesterday's pioneers relied heavily on forts and outposts to offer refuge from the challenges they faced. The adventurers of the 21st century might need to rely on something similar—a space station.
Humanity has already launched and sustained quite a few space stations, though all have remained tightly in the grasp of Earth’s gravity. The Soviet Union had the Almaz and Salyut space station programs, and later the Mir space station. The United States’ first space station was Skylab, which remained in orbit from 1973 to 1979.
Fast forward to today, and we have the International Space Station (ISS) whizzing around the Earth at 27,600km/h (that comes out to about 17,100mph). A crew of six multinational astronauts calls the ISS home on any given day. China launched their first space station, the Tiangong-1, in 2011, but they have not sent any new crew members to the station since 2013.
Many innovations have been tested out on the ISS including inflatable habitation modules, robotic crew members, autonomous drones, and zero gravity 3D printers, to name a few. These tools might become more commonplace on next-generation space stations. Russia, China, and the United States have all announced planning efforts for followups to both the ISS and Tiangong-1. Cooperation between these three countries remains tentative at best, but all plans look to a mid-2020 timeframe for the launch of the new space stations. Meanwhile, the European Space Agency has been actively seeking plans for a lunar colony as well.
There is no doubt that the next-generation space station will be technologically more forward regardless of what path is taken. However, what can we expect from the space stations that will exist in 100 years? Or 200 years?
To answer that question, we might consider closing our history textbook and turning on some science fiction.
Babylon 5, Deep Space Nine., and the Death Star; arguably these are three of the most well-known space stations of science fiction lore. There have also been many takes on the ring-like space station such as Space Station 5 from Stanley Kubrick's masterpiece 2001: A Space Odyssey, and the more recent Elysium. If you are looking for a few laughs, there is the Satellite of Love made famous by the comedy show Mystery Science Theater 3000. But for now, let’s focus on the big three.
So how do these celestial outposts compare?
Size: 120km (diameter)
Personnel: Approximately 2.5 million
Mission: Military weapons system
The sheer size of the Death Star from Star Wars makes it both awe-inspiring and also highly improbable that we would ever attempt to actually build a version of it. Some folks have tried to estimate the costs of such an endeavor and they range from a few a hundred quadrillion dollars to a few dozen sextillion dollars. A sextillion is a one followed by 21 zeros. Sort of makes the US.deficit seem rather insignificant in comparison.
From a technical perspective, building the super laser would probably be the greatest challenge. Generating and storing the amount of energy needed to destroy a planet in a single blast of deadly flaming green radiation would require a significant engineering effort. Perhaps our future space stations would benefit from less powerful but still potent directed energy weapons to destroy debris that posed a potential impact danger.
Another key feature of the Death Star is the tractor beam, much to the chagrin of intergalactic smugglers. Tractor beams allow for controlled and precise movement of inbound spacecraft carrying supplies and personnel to the Death Star. After all, nothing ruins your day like a runaway space shuttle colliding with your inhabited space station. Might we employ such technology on our future space stations?
Size: 8km (length)
Personnel: Approximately 250,000
Mission: Diplomatic hub
While the Death Star is an instrument of war, the Babylon 5 space station is a tool for peace. It also has a diminutive stature compared to the Death Star. The design of Babylon 5 was inspired by physicist Gerard K. O'Neill’s vision for space stations, a concept known now as O’Neill cylinders. An enormous motor built using electromagnetic bearings generates a rotation of the central cylinder, which results in artificial gravity for the station inhabitants. Artificial gravity might very well be necessary for future explorers so as not to be afflicted by health issues that arise from prolonged exposure to zero gravity. NASA astronaut Scott Kelly recently returned from a year aboard the ISS and noted some minor but still significant medical challenges resulting from the absence of Earth’s gravitational pull on his body.
The design of Babylon 5 is surprisingly well thought-out from an engineering perspective. It is divided into six sectors, each with their own functionality. The Blue Sector contains facilities for command and control, administration, medical care, and docking bays. The Red Sector provides the housing accommodations and recreational facilities. Food production and environmental systems are controlled from the Green Sector. Mechanical systems are housed in the Grey Sector, while the station’s power plant is located in the Yellow Sector. Lastly, the Brown Sector contains facilities for transients as well as for manufacturing, maintenance, and waste handling. In short, it is a small, self-contained city. Future engineers might very well look to this type of segmentation in designing larger, more long-term space-based habitats.
Babylon 5 was built to serve as a neutral location for a variety of species to interact. Thus, the environmental control systems of the station must be dynamic enough to meet the needs of aliens with a variety of life-sustaining atmospheric needs. A monorail train runs the length of the rotational axis of the station by taking advantage of the fact that an O’Neill cylinder has zero gravity along that axis. Babylon 5 also features a double hull to give itself protection from any damage that could be caused by impacts from meteorites and other small debris. While we might not have a need for mass transit in our future space stations, protection from debris and efficient environmental control systems are absolute must-haves.
Deep Space Nine at a Glance:
Size: 1451.82m (diameter)
Personnel: 300 permanent inhabitants, accommodations to support up to 7,000
Mission: Mineral mining and refinery
The final space station, Deep Space Nine, is also the smallest of those examined. Built by the non-human species known as the Cardassians, Deep Space Nine’s original function was mineral and ore processing. Undoubtedly, DS9 has the need for a robust and extensive industrial control system to safely handle that role. The layout of the station is reasonable as well, with a central core surrounded by two concentric rings. The core housed the majority of the facilities including operational, administrative, commercial, industrial, and mechanical spaces. The smaller inner ring provided housing for the crew and visitors, while the outer ring and its massive pylons provide the infrastructure needed for starships to dock with DS9. Again, smart layouts will be necessary for our future real-world space stations.
DS9 residents do not have to worry about a lack of resources thanks to their replicator technology. The capability of converting energy into matter in a controlled manner means the only thing standing between you and a hot meal or a shiny new screwdriver is a simple voice command. Imagine asking your Amazon Echo for an item, and having it 3D printed right in front of you in mere seconds! This type of innovation may very well prove to be important. Getting to space is all about weight. The more you take, the greater the cost of getting it all launched into orbit. Instead of taking spares for everything that goes with us, we could simply take raw materials and fabricate replacement parts on the fly thanks to futuristic additive manufacturing technologies.
Another unique facility aboard DS9 is the holosuite, a sort of immersive virtual reality experience without the necessity of donning cumbersome eyewear. The holosuite provides an entertainment venue for station personnel, which is crucial to their psychological well-being since they are otherwise trapped on a rather static cosmic island. Such amenities that take care of the human mind in addition to the human body will no doubt be critical for mission success in tomorrow’s real-world space stations. This will be especially true as space stations become bonafide colonies and not just orbiting science laboratories.
War. Peace. Commerce. The mission of these space stations may be diverse, but there are many similarities when viewed from a technical perspective. So just as soon as we sort out artificial gravity, tractor beams, directed energy weapons, advanced life control systems, immersive virtual reality, next-generation 3D printers, and a few other technologies, we should be all set for the long-term habitation of space. It will be curious to see which, if any, of these concepts escape the realm of science fiction to become technological fact.
Michael Parks, P.E. is the co-founder of Green Shoe Garage, a custom electronics design studio and embedded security research firm located in Western Maryland. He produces the Gears of Resistance Podcast to help raise public awareness of technical and scientific matters. Michael is also a licensed Professional Engineer in the state of Maryland and holds a Master’s degree in systems engineering from Johns Hopkins University.