Hi! I'd like to recommend you to participate at NASA Space Settlement Contest! This is the link to their website:                 http://settlement.arc.nasa.gov/Contest/            
          In the next pages you can see a part of my project.    

                                                                Introduction                     

In the future human race will experience a major problem: overpopulation. The number of humans is continuously raising and the cities are constantly expanding. The need for resources and space will grow to an unimaginable level.

The planet Earth won’t be able to support the technological evolution, to sustain life of a species that is seeking its hidden treasures and uses them for its own development. The forests will be almost entirely chopped down and replaced by buildings, the oil and methane  gas will be long time ago depleted, entire species of animals will be extinguished forever and their habitats will be engulfed by cities.

        Mother-Earth cannot help her son, the human anymore. This mother cannot keep him home any longer, not just because it cannot satisfy his physical needs anymore, but also because it cannot satisfy his need for knowledge.

        It’s the natural way that children leave their nest when they grow up, after they have learnt enough to carry on by themselves.The mankind has the innate desire to discover new places, to learn more, to solve new riddles, so he won’t settle anywhere, he will seek relentlessly the unknown, he will undauntedly try to conquer the last frontier ….the outer space.

Short presentation

             Alphekka space settlement is the perfect solution for  the human society future problems. It offers people the possibility of living in space, independent of Earth, but in conditions that reproduce the features of their original habitat. The stability and security offered by the settlement make it a genuine new home, where man can easily live and work.

It offers the humanity the possibility of developing using the unlimited outer space resources, it offers freedom to explore, knowing that there are no boundaries anymore.

             Alphekka doesn't only solve the overpopulation problem, but it is the way that human will continue to explore the universe. It is a pioneer space settlements, it is the model for more performant settlements that will leave the solar system and ,who knows,  maybe our galaxy in the search of new worlds to visit.

Location

Alphekka will be built in the vicinity of Earth, due to the relatively facile access at Moon’s and Earth’s resources. The question that remains is where to place the space settlement. We are looking for a very stable place.

For the a two-body system, there are 5 possible equilibrium points, called the Lagrange points.,where the third , having a mass much smaller than the masses of the previous bodies, can be placed. The most stable ones are L 4 and L 5 we've decided to place it in L 4.

           SPACESHIP PRESENTATION

           The spaceship has five major components:

    A. central axle

    B .inner cylinder

    C. exterior cylinder

    D.2 space docks

    E. 2 storages and robot centers

Component	Dimension	Numerical value
Central axle	Height( hA) Height A2(hA2) Radius A1(rA1) Radius A2(rA2) Volume A2 Surface A2	1200 m 800m 100m 200 m 100.530.965 m3   1.005.309m2
Inner cylinder	Height(hB) Radius B1(rB1) Radius B2(rB2)  Total Surface Living area Volume	900m 600m 530m 6.887.000 m2 3.392.920 m2 223.650.000 m3
Exterior cylinder	Height(Hc) Radius C1(rC1) RadiusC2(rC2) Total surface Living area Volume	450m 950m 890m 5.284.500 m2 2.686.062 m2 156.074.323 m3
Space docks	Radius D(Rd) Height D(Hd) Surface Volume	200m 210m 270000 m2 26.389.378 m3
Storages	Height E(hE) Radius E(RE)    Aprox.Surface   Aprox.Volume	200m 170m 213.628m2 18.000.000 m3
Here are Alphekka components, presented in detail

2.4 ROLE OF THE COMPONENTS

            The central ax has a crucial role for the spaceship stability, being connected to each of the two cylinders (connecting them indirectly). The  storage, the robots fixing centers ,the two space docks and the zero- gravitation laboratory are situated on the central ax, making it the main part of the spaceship assemble. It has also a big role in entertainment, having a zero-g room for those who want to experience a few hours without gravity.

            The inner cylinder is reserved exclusively for the residential area. The internal management and business centers, the apartments , the shops , the schools , the hospitals as well as  parks and night clubs( recreational and entertainment areas) will be situated on its inner surface The inner cylinder is the  equivalent of a town center, not just because of  its placement relative to the rest of the spaceship , but also because of its importance and building types.

            In its interior will be grown a part of the animals needed for human consume, because animals, as well as humans need a good isolation from noise and other pollution types.

The exterior cylinder is reserved exclusively for industry and agriculture. All the factories and the machines are situated in its interior, as well as forests and other plants needed in industry or human consume( for clothing, cereals etc) and most of the ranches. This cylinder will be  divided in several levels, so the industrial zone will interfere as less as possible with the agriculture area.  In its interior will be situated some apartments and some hospitals but in a significantly smaller proportion than in the inner cylinder and only for tasks that demand continuous human intervention.

            The two storages have a very good positioning, being connected to the space docks and they are  easy to access of the space modules, which are moving on the resistance structures or the external skeleton(see…). Here, there will be stored the construction materials, the minerals arriving from space(which will be furthered transported to the exterior cylinder for the industrial activity) and also there will be deposited the water, the storages being also a decontamination place not just for it, but for all the materials and humans that arrive from outer space .

            Robot centers (part of the storages) have the main role of being the area where robots are fixed and programmed. They also have an importance in the transportation of resources, being the place where space modules are loaded with materials that are needed in the industrial area.

       

                                    The Metal exosckeleton

    Role:- connects the central ax with the exterior cylinder;

                -robots can use it to transport freight from the storages to the exterior cylinders( rail       track for robots)

                -increses the stability of the spaceship

2.5 Rotation mechanism

The illusion of gravity in the spaceship is due to the rotation of the cylinders( the gravitational force is actually the centrifugal force)

This is the condition to have a gravitational pull, similar to that on Earth:

w2R=g

where w is the angular velocity, R is the radius of the cylinder and g is 9.81m/s2

It is obvious that g must be the same on both cylinders, which poses a major technical difficulty  The solution to the problem is a central ax made of two components that rotate separately and slide with very little friction.

            In order to minimize the friction force between the A component and B component, liquid Helium will be inserted to fill the gap. At very low temperatures( like those in space),  Helium acts as a super fluid, having almost 0 viscosity! Super fluids all have the unique quality that all their atoms are in the same quantum state. This means they all have the same momentum, and if one moves, they all move. This allows super fluids to move without friction through the tiniest of cracks, and super fluid helium will even flow up the sides of a jar and over the top.

Of course, there will be a small nonzero  friction momentum still acting on the system, but the rotation can be maintained steady, using air and fuel jets, thursted in order to balance the effect of friction. The eliminated air is actually waste-air( polluted air).

           The excess air will be directly eliminated in space, producing a rotation momentum that , together with a jet fuel momentum,will balance the friction momentum( that’s how the two cylinders will keep their angular velocities constant). The inner cylinder has a greater rotation speed than the exterior one. The friction momentum tends to bring them at the a synchronous rotation. That’s why the inner cylinder is decelerated and the exterior cylinder is accelerated.

Exterior transport

The exterior transport, from one cylinder to another poses a lot more construction difficulties and requires a great amount of innovation.

Problems:

•              The two cylinders are spinning with different angular velocities, so they cannot be simply connected , so the rails must be fixed on just one cylinder(we chose the exterior cylinder, because of its higher energy production)

•              This leads to another problem, because the rails will have a relative speed to the inner cylinder. It means that the transport of people and things from the train to the inner cylinder is hard to realize

•              The train will ascend vertically on some paths of the rail tracks (vertically means against centrifugal force), so a mechanical system is required to make the train move against gravity and also make him move on horizontal

tracks.

•              The track system might be unstable.

Here is the design that we propose for Alphekka rail tracks 

This is how the exterior cylinder, with the rail tracks attached look like

This is just one of the three tracks attached of the exterior cylinder

The track is passing very close of the inner cylinder, but there is no contact between the transport system and its exterior surface. The rail is attached of the exterior cylinder by 4 titanium supports.

View from above of the rail system.

You can observe that it presents 3 symmetry axes.  

The movement is only mechanical, due to an electrical engine placed in each train compartment that has the role of spinning the special lateral wheels. The lateral zipped tracks enables the existence of a traction force that balances the weight of the train.

There are also another 4 simple rails that assure the stability of the train. If anything happens to the trains during its movement, a blocking system will be activated and it will remain suspended until robots will fix the damage.

A difficulty of this system is the displacement of people from the train compartment to the interior of the inner cylinder, because of the relative angular velocity of the tracks at this junction.

The solution is simple and that explains the shapes of the tracks presented above.

The transport of the people has 5 stages.  In the next section we will present the transport cycle.

                        The transport cycle

In the next images is shown how the displacement system works, for only a train compartment. Each compartment it’s attached to its own wall exit. Because of the limited time, the passenger exchange must be made as fast as possible and in complete safety.

Stage	Processes	time	Image
Stage          1	·         The train is aligned with the exterior cylinder’s exits ·         The protective envelope attaches to the cylinder and the all the traps are opened ·         A platform is moving the passengers to their seats and take ·         The passengers that were already in the train move to the platform ·         After the passenger exchange has been made the envelope is detached, and all the traps are closed	25 s 30 s 45s (both processes occur in the same time) 30 s
Stage 2	·         The train starts moving on the rails and reaches point A with the same speed of the inner cylinder surface	6m 30s
Stage 3	·         The train is aligned with the exterior cylinders exits Observation: it is moving with the same speed as the exterior wall of the cylinder. However, the train is still moving on the tracks, due to the relative speed between the rail system and the inner cylinder. When the protective envelope is finally detached, the cylinder has already reached the point B. As you can see , the time available for people displacement is limited which make this stage the most risky one ·         The protective envelope attaches to the cylinder and the all the traps are opened ·         A special ladder is descending for each passenger( the new passengers are brought to their seats with the ladders and some are taken and automatically brought them in the cylinder) ·         After the passenger exchange has been made the envelope is detached and all the traps are closed	20 s 35 s 40 s 30 s
Stage4	·         The train starts moving and  reaches point C with the same speed as the exterior cylinder wall	6m 30 s

                                          Exchange features

The new passengers won’t have the same seats with the ones leaving the train, because we want to prevent any contact between the passengers that would disturb the normal activity. That means that during the inter-cylinder travel half of the seats are not occupied. There will be entire train compartments left empty for the incoming person .After the exchange, the other half of the train gets empty.The protection envelope is made of multiple layers of Kevlar, which makes it highly resistant to mechanical stress.  Also it offers radiation protection and thermal isolation due to other materials in its composition.It is fixed on the  wall with strong electromagnets which assure a good isolation from outer space.

The exchange at the interior cylinder is risky, because there is a limited time to make it.  Calculus shows that the available time is about 3 minutes:

 OBSERVATION

In the AB region there will be no metal bars like those presented in the below image, in order to permit the train with the envelope detached and attached to the inner cylinder to move freely.( the train is moving relatively to the rails so their existence would make the exchange impossible . The rails in AB region are stronger and thicker in order to prevent accidents

    g= 9,81 m/s2

R exterior= 950m

R interior= 600m

Ω interior =√(g/Rinterior)= 7,326 degrees/second

Ω exterior  =√(g/Rexterior) = 5,822 degrees/ second

Ω relative=Ω interior –Ω exterior =1,504 degrees/second

The available angle, α=273 degrees

Time=α/(Ω relative) = 181,51 s

Stage 3 lasts 125 s, so there are about sixty seconds available to correct any mistake.

Possible errors	Solutions
The isolation from outer space is not good enough(the envelope doesn't attach to the wall)	The passenger exchange will be stopped in the respective compartment. The train will continue his course and robots will fix the problem.
The ladders block during people displacement( the automatic system crashed)	If the ladders block before they start descending, the displacement will be simply stopped in the respective compartment and will suffer only a delay until the problem is fixed       If the ladders started to descend when they blocked, they will be manually controlled. People will remain in the train or will be brought in the cylinder, depending on the stage of the exchange when the blocking occurred). The manual control takes longer, but it can  be easily made in time)
Worst case scenario: ladders descended and cannot be controlled automatically and manually	Although it is extremely improbable, it still can happen and Alphekka must be prepared to face this situation.      On the laterals of the train interiors there are safe-zones, where people will enter and will be secluded from the outer space.     The station area will be evacuated and isolated from the rest of the settlement, in order to protect the residential area from any damage that may occur at the station.     The envelope will be detached, but the ladders will remain still. They are designed to easily deform under a relatively small force acted on them, so no serious damage will be produced to the train, station area or the rail system. ( they will be made to brake at a force bigger than 3500 N, so they can be used for lifting people, but cannot deform the titanium-iron walls.

                                 
                          Interior transport

The interior transport will exist only in the exterior cylinder, because of its bigger dimensions and need to transport tones of materials and food from one place to another as fast as possible.

In order not to disturb industrial and agriculture activity and to let more space available for buildings, the rail won’t be place on the floor, but on the ceiling. Exactly, when a Alphekka resident is looking up he will see trains moving above him.

The trains are maglev type, using electromagnets to move and levitate. Unlike Earth’s maglevs, Alphekka’s maglevs have the rails above the chairs.(it looks upside down).

The train stations are situated up, mounted on buildings that connect the two walls of the cylinder (the outer and inner one). People use special elevators controlled by computers to ascend to the top.

ENERGY

The main energy source is the solar energy, gathered by the solar panels mounted on the exterior cylinder. The total area of the solar panels is about

2.500.000m2( aprox the area of the exterior

The effective area, however is smaller( see figure), of about 

2*Hc*rC2=855.000m2( effective area is a rectangle )

Recently, in 2012, embattled photo voltaic solar power manufacturer Amonix announced on Tuesday that it has broken the solar module efficiency record, becoming the first manufacturer to convert more than a third of incoming light energy into electricity – a goal once branded "one third of a sun" in a Department of Energy initiative. The Amonix module clocked an efficiency rating of 33.5 percent.

           

Probably, the efficiency will be increased by the time the settlement will be ready to orbit the Earth( aprox 2080). I’ll take the efficiency factor 0.5 in my calculus from now on. The Solar Constant S is about 1370W/m2 in Earth’s region.

Therefore, the power that can be produced on Alphekka is

P=1370*855000*0.5W=0.585 GW

The energy available in one year is therefore:

E=18448 TJ or 5124,4GWh, which is more than enough for a population of only 10000 people.

In fact, the energy gain is so big, that Alphekka will provide Earth continuously energy, in the form of chemical energy, that can be transported in spaceshutlles.( transport via LI-Ion Batteries)

The United States usage of energy  person was 87kWh during 2008.Thus, we can approximate that the energy consumption on Alphekka will be about 0.87 GWh, much smaller than Alphekka’s gain.

The solar energy is stored at the energy centers located in the exterior cylinder. From here, the energy is distributed in all the settlement.The energy is distributed in two ways: directly( using electic wires) and indirectly( the energy is stored and transported as chemical energy- Li-Ion Batteries)The second method is used especially to transport energy from the exterior cylinder to the inner one.

Another energy source is algae-derived biodiesel

Studies show that some species of algae can produce up to 60% of their dry weight in the form of oil. Because the cells grow in aqueous suspension, where they have more efficient access to water, CO2 and dissolved nutrients, micro algae are capable of producing large amounts of biomass and usable oil in either high rate algal ponds or photobioreactors. This oil can then be turned into bio diesel.

Advantages of Algae:

• Are among the fastest growing plants on Earth
• About 50% of their weight is oil

The Graph below shows the production Yield for different plants.

The yield shown of 3500 gallons of oil per gallon is for obtained for a harvest rate of 10g/m2/day, using algae with a 15% percentage of triglycerides.

Using algae with 50% percentage of triglycerides and for a harvest rate of 50g/m2/day a result of 30000 gallons of oil / hectar can be achieved!

Most companies pursuing algae as a source of biofuels pump nutrient-rich water through plastic or borosilicate glass tubes (called "bioreactors" ) that are exposed to sunlight (and so-called photobioreactors or PBR).

Running a PBR is more difficult than using an open pond, and more costly, but may provide a higher level of control and productivity.

The microalgae broth is circulated from a reservoir, most commonly a degassing column, through the solar collector tubes and back to the reservoir. As the microalgae flows through the photobioreactor tubes, photosynthesis generates oxygen (Chisti, 2007). Dissolved oxygen levels significantly exceeding that of air will cause the inhibition of photosynthesis (Chisti, 2008). Accumulated oxygen cannot be removed within the tubes; therefore, the maximum tube length is limited (Molina, Fernandez, Acien, & Chisti, 2001).  Accumulated oxygen is removed from the broth through frequent recirculation through the degassing column.  The volume of the degassing column must be less than that of the tubes to optimize cell growth. The murky nature of the broth limits the quantity of light exposure while the broth is in the degassing zone. Extended periods of reduced light exposure negatively affect the rate of cell growth.

 algae crops

A pump drives the recirculation through the system. An airlift pump is recommended for the system because it is less likely to damage the biomass and more reliable (Molina, Fernandez, Acien, & Chisti, 2001). It is necessary to have highly turbulent flow through the solar tubes to minimize sedimentation (Chisti, Biodiesel from Microalgae Beats Bioethanol, 2008). As the broth flows through the tubes, the sunlight heats the broth. Therefore, the broth must be cooled within the degassing column to maintain the optimal temperature between 20 and 30°C (Chisti, 2008). CO2 must be added throughout the system to maintain a constant pH (Carvalho, Meireles, & Malcata, 2006).