An effective design project needs to begin with a set of precise and realistic requirements and constraints. Even at this early stage, there are two sets with which to get started on systems for permanent habitation. The first are requirements for human life:

• A habitat shall provide substantial gravity • A habitat shall provide adequate utilities services in a reliable manner • A habitat shall provide an environment without hazardous levels of radiation • A habitat shall remain structurally and functionally adequate and sound for not less than TBD decades.

The second set are requirements for successful operations:

• A habitat shall support ship operations at multiple ports • A habitat shall keep its center of rotation sufficiently close to the geometric center to enable effective and safe operations • A habitat shall keep its precession properties small enough to enable effective and safe operations.

These are given requirements.  These are always followed by derived requirements that arise from the given requirements.
These requirements are sufficient to enable conceptual design efforts.  They would be greatly expanded before a construction effort begins.

Most of the ground work has been already done with regard to defining an in orbit space habitat; The likes of O'Neill (http://www.nss.org/settlement/physicstoday.htm) and Heppenheimer (http://www.nss.org/settlement/ColoniesInSpace/index.html) have with funding from NASA, established the feasibility of building large habitats. We now need to take these proposals and adapt them. Technology has moved on, and the chief stumbling block of launch costs is now being addressed by commercial companies. If we are serious and can obtain funding this could be accomplished within twenty years.

As far as building space colonies go, there are right ways and very wrong ways, depending on the its purpose and needs. Asgardia is a nation-to-be with hundreds of thousands of citizens. If all were selected to go to space, a prospect in which I am dubious but no expert, it would take a true megastructure to house and care for them all in any level of comfort or practicality. The following are some of my views on the subject. Here is some background info to explain why my opinion even matters a little or where my information comes from, I am currently in the process if finishing up my bachelor of science degree in aerospace engineering with heavy emphasis on mechanical design and applied physics. My step father is also a project lead and aerospace engineer working for Boeing and I practically got his degree with him as we studied together daily. I know everyone reading this is not math savvy or knows all of the technical jargon, so I will attempt to minimize both where I can and explain as in-depth as possible where I cannot avoid one of the other or both. First hurdle to overcome is cost. There is no getting around this, folks. Any structure in space is costing hundreds of millions minimum and many billions for what we would need. Perhaps hundreds of billions. That is if we do things the conventional brute force way. There are many work arounds that can be strategically deployed and employed to bring costs down sharply. Unfortunately, though, these as well cost a lot in terms of initial investment. As with the colony itself, there are methods to offset the costs. We will touch on that later. Still, the original funds must be garnered and expended. The good news is that Asgardia does not have a shortage on the most valuable resources of all: manpower and drive. Expertise and funds can be obtained over time. With 570,000 plus Asgardians, the manpower is there in spades. The will and drive and imagination are there, too, because the philosophy of Asgardia and its core mission and values are what drew most of us to it in the first place. People can be sent to academies to learn the needed skills, and enterprises and investment arrangements can be made to garner the finances. In my view, the hardest two resources, drive and manpower, has already been achieved. How many other movements has as many people who are ALL willing to donate their time and energy and minds to one singular goal they believe in this much? Progress would be astounding if aimed right. How can we effectively bring costs down? Many of the same ways we do so on Earth. When you want to first bring goods or services or even a population to an undeveloped area, everything is costly. There is no infrastructure in place to aid you. You must to it all yourself or bring help from home. There are several kinds of infrastructure that could make building and maintaining a colony or colonies easier and cheaper. First is the issue of getting things off the planet in the first place. Rocket launches are expensive. It costs an object its weight in gold or more to launch it into space. Roughly 10,000 US dollars a pound. Obviously the first order of business is to get that number down. How do we do that? Everyone speaks of space elevators they see in various forms of media. These are not possible by current technological or economical means. All substances have what is called its maximum breaking length, the longest it can be before it breaks under a specific amount of force. No substance we can currently mass produce economically possesses the tensile strength needed to make these. Graphene and carbon nanotubes can potentially, but we cannot produce either in large quantities cheaply or at all. So, what does that leave? There are a few options, each with its own pros and cons. First is a Sky Hook. These are basically thick and long poles with attachments on at least one end that allows a ship to dock with the structure. These poles spin horizontally, similar to the way a baton spins in the hand between one’s fingers, as they orbit the Earth. One end of the hook will at times dip into the upper atmosphere for a short while. At this moment, a ship can rendezvous with the Sky Hook and attach to it at suborbital speeds by being at the right place at the right time. The rotational energy of the structure will then “drag” or “pull” the ship into orbit. That is a simplification, but it is the overall concept. The advantage of these is low building cost relative to the other options I am about to mention, little power usage, and its relative simplicity. Also, we can build these with current tech. The downsides, though, are getting these things to rotate and orbit in the exact way needed to work as intended is very difficult. Also, each time a ship docks with the hook, it takes away some of its rotational energy, meaning the structure will need boosted from time to time or have a limited number of uses. Having rendezvous times limits the number of launches possible as well. One could have many of these in orbit but then you run into the problem of having to track them all as to never have anything else going up collide with one. Not the most practical choice.

Next is the equally unimaginatively named Space Fountain. This works in many ways alike how a space elevator functions, though via very different means. A Space Fountain does not require extremely strong materials to construct. This device basically acts as a continuous coil gun with captive projectiles caught in a repetitive loop. In one of the more commonly accepted designs for a Space Fountain, a stream of projectiles is shot up through the bore of a hollow tower, usually a tube, at around 14km/s. As the projectiles travel upward through the tower they are slowed down by electromagnetic drag devices that extract kinetic energy from the upgoing stream and turn it into electricity. As the projectiles are braked they also transfer some of their upward momentum to the tower structure, exerting a lifting force to support some of its weight. When the projectiles reach the station at the top of the tower they are turned around by a large bending magnet. In the turnaround process, they exert an upward force on the station at the top of the tower, keeping it levitated above the launch point As the projectiles travel back down the tower they are accelerated by coil guns that use the electrical energy extracted from the upgoing stream of projectiles. This provides the rest of the upward lifting force required to support the weight of the tower. The projectiles reach the bottom of the tower with almost the same speed that they had when they were launched, though losing a small amount of energy due to inefficiencies in the electromagnetic accelerators and decelerators in the tower. This can be minimized by the use of superconductors, however. When the stream of high speed projectiles reaches the bottom of the tower it is then bent through 90 degrees by a magnet at the tower's base so that it is traveling parallel to the Earth's surface, through a large circular underground tunnel similar to a particle accelerator. Electromagnetic accelerators in this tunnel bring the projectiles back up to the original launch speed, and then the stream of projectiles is bent one more time by 90 degrees to send it back up the tower again to repeat the cycle. The downward force from the weight of the tower is transmitted solely by the stream of projectiles to the bending magnet at the tower's base, and so no materials with extraordinary compressive strength are required to support the tower itself. The tower's base, however, does require a foundation capable of supporting the weight of the tower, but this can be constructed with traditional materials able to be mass produced cheaply on Earth. Together, the stressed structure and flowing projectile stream form a rigid, stable structure that is not limited in height by the strength of materials. The lower parts of the tower would have to be surrounded by an airtight tube to maintain a vacuum for the projectiles to travel through, reducing energy losses due to drag. After the first one hundred kilometers or so the tube would no longer be necessary and the only structure that would be needed is a minimal framework to hold communication and power lines, and the guide tracks for the elevator cars. When the projectiles return to the base of the tower they have nearly the same speed and energy as they started with, only with the opposite momentum (downward instead of upward). As a result, the input power required to support the space fountain is determined by the inefficiency in the electromagnetic motors and air drag on the projectiles. The projectiles used are usually iron pellets, but other metals highly affected my magnetic forces could also be used. Iron just happens to be commonly available and relatively cheap. An upside to fountains is they do not require having to get a payload up to escape velocity. The elevator rises at any speed. The downside to Space Fountains is the energy budget needed to sustain the things. The device would require a constant feed of power to hold itself up. They are held aloft only by the electromagnetic forces at play. Should live power ever be lost to the system, it all comes crashing down, literally. Some safety measures can be taken, however. Redundant projectile loops and power supplies could be added to the system. In the case of a loop failing, the others could maintain the structure while repairs could be made. Usual operations would not have to necessarily cease in such an event. Any payload being raised would likely be designed as re-entry vehicles anyway, and could be jettisoned during a critical failure. We have been making re-entry capsules that can do this for decades, so this concept would be far from new. Also, even if all power sources were to fail simultaneously, it would take hours or even days before the tower begins to fall. The projectiles are traveling through a vacuum, so the kinetic energy they carry would take some time before being slowed by gravity to the point the structure begins to suffer. This energy is more than sufficient to keep the tower aloft for quite some time. Due to the fact it takes some hours for the stream of projectiles to make a full loop, there would be a window of some time for evacuations. Third, we have my personal favorite, the mass driver. This works nothing like the others. A mass driver is basically a bullet train on steroids. A very long track would have to be constructed, and the grade of the track would have to change gradually over much distance from horizontal to near-vertical. Using electricity, the payload is launched down the track at very high speeds. Like mag-lev trains, the craft would actually hover due to electromagnetic forces at play. Payloads could be accelerated to escape velocity or to speeds where much less conventional propulsion is needed to achieve orbit. To achieve maximum efficiency, most or all of the track should be within a tube that is pumped to vacuum. This would eliminate or sharply reduce aerodynamic drag that would slow the craft, robbing it of kinetic energy and requiring more power to get it up to speed. The entire length of track need not be in such a tube, however. The atmosphere thins the higher up one goes, so there would be a point as which the craft could leave the tube and drag would be only of minimal concern. This also affords the advantage of only having to have shielding for heat on craft meant for re-entry, reducing weight to payloads that are intended to remain in orbit, thus requiring less power to accelerate it. Some designs call for a more catapult-like approach. Instead of the entire craft being accelerated and launched, a holder would carry the actual craft and launch it down the track. The craft would leave the track to enter orbit and the holder would return to be reused. This has the advantage of not having to load an entirely new platform each time, just the craft carrying the payload. The upsides to mass drivers are many. First, it uses already established technology and only needs scaled up. Space Fountains and Sky Hooks both require new studies and testing to get the engineering perfect. Some of this would be needed for mass drivers, though nowhere near as much. The system also only needs to be powered when launches are made, not continuously like a fountain. There are concerns, however. The track needed for these would need to be well over a hundred kilometers long and rise very high. The vacuum tube would likely have to start underground, requiring a lot of earthwork to construct. The supports to these things would run kilometers high in some designs. This is very doable, but expensive and requiring a lot of materials. The system also requires a lot of maintenance compared to the other options, another expense. Still, I believe this is the best option for obvious reasons. The Startram design claims to be able to get a pound of material into space for as little as 50 US dollars compared to the 10,000-dollar price tag of conventional means.

Once an infrastructure is in place to get things into orbit cheaper is established, more possibilities open up. Infrastructure in space, to name one. It would be much cheaper to construct a colony in orbit versus sending everything up, even with things like Sky Hooks, Space Fountains, or mass drivers. Setting up a construction yard in space simply makes sense. Pieces of the colony can be made on Earth and sent up to accelerate progress, but it makes more sense for the thing to be built mostly in space. The solar system is littered with raw materials, the nearest source being our own moon. Asteroids are also considered viable sources of material. By having a construction and mining apparatus in orbit, the cost of building a colony would be very much lower. Also consider the commercial applications. If Asgardia has such a system in place, things could be constructed in space for governments and corporations much more cheaply than on Earth. We could charge a fee for building these things in orbit that would reduce costs for the entity buying the product. Even the launching systems would produce revenue and offset their costs. If Asgardia could launch a pound of anything into space for as little as $50 a pound, many entities would seek having their payloads launched at much lower costs than exist now. Asgardia could charge to launch these things. Say we have a cheap launching platform and a construction/mining operation in space. Then what? We should address exactly what it is we should build. This requires looking at the purpose and needs of the colony. At first, it is likely only one station be built. Building many is unrealistic right away. The first would likely be a smaller structure for proof of concept to get the science down. Once that is established, the real project can begin. If Asgardia decided to put all of its citizens in space, and we should, in my opinion, we would need a structure capable of sustaining over a half-million people. This is no small endeavor. There are three classic designs currently accepted. The Bernel Sphere, the Stanford Torus, and the O’Neill cylinder. I will touch on each. The sphere and torus are both very stable when spun for centrifugal gravity, but they are limited in scope. The wide diameter that gives them this advantage also puts a lot of strain on the materials from which they are made when spun. Simply, they can only be made so big. Either could hold most of Asgardia’s population, but there would be little room left over for recreational centers and industry. The O’Neill cylinder instead is slimmer in diameter than some other designs, but much longer. The length of a habitat is not at all limited, save for the amount of material used to build the structure and the cost. These measure 20 miles long and five miles in diameter. The latter is very important. There exists an effect called the Coriolis effect when one uses centrifugal force for gravity. This is where the revolutions per minute of the structure interacts with the fluids in one’s ears that maintain balance to cause nausea and other effects. Trained personnel can withstand up to twenty rpm, but that will not be most Asgardians. What is the magic number for regular people? That is 2 rpm. Asgardians could train to sustain higher rpm, but this would eliminate any chances for space tourism to the station. Ordinary people would not be able to visit, and this would cut out a potential source for revenue.

Simulating 1G RPM/ Diameter (feet)/ Diameter (meters) - 24.2/ 1/ 3 | 10.8/ 50/ 15 | 7.7/ 100/ 30 | 5.4/ 200/ 61 | 3.4/ 500/ 152 | 2.4/ 1000/ 305 | 2/ 1467/ 447 | 1/ 5868/ 1789

Material/ Tensile Strength (MPa)/ Breaking Length (km) Nylon 78/ 7.04 Aluminum alloy 600/ 21.8 Stainless steel 2000/ 25.9 Titanium 1300/ 29.4 Spider silk 1400/ 109 Kevlar 3620/ 256 Zylon 5800/ 384 Carbon Nanotube 62000/ ~5000

As you can see, things must be very large in order to remain under that 2 rpm limit. Also, there is a limit on size due to the breaking point of materials. Of all the ones I listed above, steel would be the likeliest material we would use as there is an enormous infrastructure in that industry already for mass production. The science of making different grades of steel is well established and it is a material that can be made in space relatively easily, as its base materials are abundant in space. As I mentioned before, the O’Neill cylinder would meet our needs with room to spare. These things are 20 miles long and 5 miles wide, which grants a living area of about 314 square miles. This could house millions of people, let alone half a million, and have room for industry, a source of revenue. Many imagine a cylinder naked to space that one can see spinning. This would probably not be the best option. Keep in mind that radiation and debris and micrometeor impacts are common in space. Shielding will be necessary. This could be a thick steel shell, costly, or the most abundant resource in the universe: hydrogen. Hydrogen is light and is pound for pound one of the best shielding materials against radiation that exists. Using compressed hydrogen as shielding reduces how thick the hull/shielding has to be to protect from micrometeors and debris, because it does have to protect against radiation also. A shell encompassing the habitat need not rotate with the habitat, which is a better prospect. Remember, spinning puts strain on materials. Also, anything that impacts the shell would add or subtract its relative velocity to that of the rotating shell, potentially causing more damage than would otherwise occur were the shell not spinning. A steel shell only a foot thick, maybe less, would be sufficient. Filling the space between the nonspinning shell with compressed hydrogen for shielding would not be a good idea either. This would need to be a complete vacuum to keep from losing rotational energy the habitat needs for centrifugal gravity. Instead large tanks of the material could be placed between the two. This hydrogen also affords the advantage of having multiple uses. It can be used to make water or as fuel. The tanks of reserve water and oxygen can also be placed this way to serve as shielding against radiation as well as being used for our purposes.

Next comes the obvious question of how we power this thing. Nuclear fission is a good option, but it has serious downsides, too. The radioactive waste would need jettisoned, though it could be used to make batteries. Also, the off chance of a meltdown instantly threatens all onboard. Current space law, I think, disallows reactors in space, anyway, but I am not too sure on that point. There are other options, though solar is chief among them. Could we garner enough energy from the sun to power a station of such magnitude? Absolutely, if done right. Having many photovoltaic cells everywhere possible is obvious, but there is another option. A constellation of satellites could be placed strategically around the station in such a way they could collect power via photovoltaic cells and beam it to a central receiver on the habitat via electromagnetic waves, which could be converted into electricity. This would allow more power to be brought to the station than if every square inch of the hull were covered in solar panels. This also helps us produce power even when the station falls into Earth’s shadow, as the satellites can be placed above this in a higher altitude or further ahead or behind in orbit. There is no limit to the power that could be received this way, as more satellites could be built and placed around the structure. Natural light could be let into the station by having no shell and parts of the hull be thick glass and using parabolic mirrors to bounce it in. I disfavor this idea as it reduces effective shielding against impacts and radiation. Still, the views of space would be amazing. This could still be done if the glass were strong enough and thick enough. Speaking of lighting, all artificial lightning should be restricted only to the wavelengths we see and those used by plants for photosynthesis. This helps with the issue of waste heat, another issue to address. The only way to get rid of excess heat in space is to radiate it away, as the Earth does. One cannot vent heated gases into the void if he or she hopes to retain the air needed to breathe and for other functions. This also limits the number of levels one of these things can have because too many makes too much waste heat which would cook everyone alive. An O’Neill cylinder can house millions, so this isn’t much of a concern. Should more real estate be needed, however, more cylinders could be built and connected via junction spheres. These would not spin and therefore have no gravity. They would need to be vacuum to keep drag from slowing the habitat’s rotation. The nonrotating shell used to shield against impacts could be directly welded to these spheres. The ends of the cylinders could be tapered so gravity lessens as you approach one. The spheres could be used for ports of entry and exit for inbound and outbound ships, and/or for zero-g research and industry. The areas nearest the sphere would have less centrifugal gravity as they are tapered, reducing the diameter. Sense the cylinder still rotates at 2 rpm or less, the lower diameter means less centripetal force. These areas could be used for training and recreation. The gravity on a station like this only exists at the interior of the cylinder’s walls. The very center of the cylinder would be zero g, meaning other places for recreational sport. Once in orbit, there are many industries the colony could get into that helps offset its costs and generates an economy. Mining rare materials is one. Conducting zero-g experiments in space for corporations and governments who pay other agencies to do similar on Earth all the time could be another. Building satellites in space from materials garnered from space is cheaper than building them on Earth and sending them up. We could build and place these in orbit for a fee that would be less than what it currently costs to send one up. Also, Asgardia could own and operate a fleet of satellites with a wide range of capabilities. Beaming power back down to the planet for a fee is one example. There are also communications satellites we could build and “rent” out or we could charge for data traffic. Orbital telescopes like Hubble or other designs could be built in space by us for a fee or we could own our own and rent them out. There is also the industry of satellite repair. When a satellite malfunctions today, the owner has to build a new one and send it up. There is no service technician one can call to repair the instruments. If we lived in space, that dynamic changes. We could reach satellites and repair them for a fee, saving the owner millions in having to build a new one and sending it up from Earth’s harsh gravity well. In closing, I want to say that these are just some points I threw together on the fly. It took me perhaps 45 minutes to write this paper and I did it virtually all from memory. All of the basic science is sound and these things could all be done today, though at great cost. I may have missed some points, though. Obviously, this would be a truly enormous project dwarfing all before it, so I cannot possibly think of everything in such a short period of time, if ever. Thankfully I have over a half-million fellow Asgardians who can add their pieces to the pot!

Brandon Stidham

I would grant a warm thank you to @Blsstidham (Brandon), for all these points you brang to us. Its enlighting so much of where we are with tech and what we could accomplish in a near future, or even now.

Awesome. The part where it is stated that "the most important thing needed to accomplish this quest is manpower and drive, which we have in abundance" gave me really hope. I believe we can do this.

A vision of what might be: https://youtu.be/KYhDu59UmSs?list=PLwN0GW971a6KeikC6dBCF9wVALFLQVVQV

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just a quick thought, ( will do a proper read of this later)

but to produce gravity we need something we can spin, would looking at potential Diamond batteries be a good idea with either EM drive (if it really works) or plasma drives to keep a sustained gravity that we can build upon?

additional question do we try and gather rocks that pass the earth to make into a space station?

Thank you very much Brandon for the highlight !

And I agree with Clive about the location at the Lagrange Point even if the position between the moon and the earth will block a part of the harvestable light.

Okay saw the questions, I will address both. There are some issues with using L1 point for a colony. A lagrangian point is a point in space where the pull of gravity is equally matched by two or more bodies, if memory serves. Using the lagrangian points has its advantages and disadvantages. L1 in the Earth-Moon system has the advantages of being placed close enough to both bodies to be highly relevent in a number of ways. Any resource procurement operations or colonies on the moon would benefit from such a station as it would be close enough to potentially act in an emergency as well as be able to relay communications. It would also serve as an Earth-moon hub for traffic back and forth. Resources being brought up from the moon or in from asteroids would likely come to this station as well. This would also be an ideal platform in which to contruct spacecraft designed for launch deeper into the solar system as it would be more economical than sending them up out of the planet's gravity well. L1 has its downsides too. It is not a particularly stable point due to gravitational interactions changing slightly over time as orbits progress. The Earth orbits the sun in an ellipse, and is therefore not equidistant from the sun at all times. This is true of the moon orbiting Earth as well, though to a much lesser extent. So any station placed here will have to undergo a process called stationkeeping, which means utilizing some thrust measures to course correct and keep its orbital plane and velocity where it needs to be. The amount of thrust needed would not be much relative to what it would take to put such a thing in orbit from Earth in the first place, but it is not negligible either. Low thrust devices such as scaled up ion drives could provide the thrust economically over time. Also the L1 point is at a high enough altitude that it only gets some protection from Earth's magnetopshere. A colony here would need a fair amount of shielding as compared to one in LEO (Low Earth Orbit). Still it would have some protection. The advantages far exceed the disadvantages in my opinion, as the problems can easily be handled with existing, established technologies. As for using thrust tech to maintain the rotation needed for centrifugal gravity, very little of this would be needed beyond imparting the original spin. It would be required over very long periods of time, though, due to collisions of space debris and micrometeors striking the hull and slowing the rotation as some of that kinetic energy is expended. This can be overcome as I mentioned in my posts by having the rotating habitat within a nonrotating shell. If this shell gets struck, it not only takes the damage the hull would have taken instead, but keeps the rotational energy of the habitat from being depleted. Also by not rotating, the shell itself would take less damage. An impactor would add its velocity to that of the rotating body if it impacts the right way, causing more damage. As to which thrusters could be used to maintain the spin over time? Existing ion thrusters would work as well as conventional rockets. As for if using the Earth-moon L1 point would be good for placing satellites for income, sure. Depending on where the satellite needed to be placed and on what orbital plane and velocity, more work would need to be done than, say, from LEO. But this could still work because building and placing satellites from this langrangian point would still be far cheaper than sending one up from Earth. The same applies to repairing existing satellites. We could still reach them more cheaply than it would cost to build one and send it up from Earth. And it is true that some harvestable light is blocked at the Earth-moon L1 point, but this is easily overcome by placing solar satellites in orbits that are not in shadow to beam power back to us. As for the EM Drive, it has passed peer review but I am not a big proponent of it just yet. I think enthusiasm for more research to be done alone is the only reason it passed. I reviewed the papers and found flaws that should have failed it. The margins of error they graphed were so wide to show readings so low they were nothing to as high as outputs beyond their expected maximum yield of the device. This tells me that they have little confidence in the values given and the consistant operational parameters of the device. Also the proposed theory as to how this device does conserve momentum by pushing against a "quantum fabric" or "vacuum" is ridiculous. The papers would have done better by getting their margins down and by simply saying "we did x tests, using y instruments and these protocols, and got a result of z. More study and experimentation needed to explain the how of it." If this device works, it shatters the standard model of physics. Newton says that momentum must be conserved, no matter the circumstance. This device propelling anything is like you sitting on a bike and propelling you and that bike forward by pushing on the handlebars. It should be impossible.

now I've read a few of the post to see where you guys are at. I think all the posts are a good read, a thought i had on money and potential station was Cruithne (earth 2nd moon). we could hollow it out, i know hollowing it out would take some serious work my initial idea was you could design a Solar laser to heat up the rock and drill through it. suck in the molten rock then separate it into materials that we could sell back to earth. i realise this would be very hard and is a little off the mad scale. additional as its some what within our orbit would reducing its mass or eventually increasing its mass change our orbit much? could potentially kill life on earth.

an additional way to make money is we work towards space hotels?

with powering such an object i think fission is a must until we work out fusion we will have to use it. unless you could heat up water from the sun with concentrated mirrors if it was always facing the sun. but that may be a bit hard :P