Ender Space Settlement Design Contest. 2014-2015 Kelly DeRees David Sugg Special Note

4.3 Microgravity Research facilities

There are eight microgravity research structures that protrude from the center section of the settlement. The structures are utilized by scientists and various researches who are studying science in zero-gravity. Experiments and activities similar to what is carried out in the International Space Station (ISS) would occur. These facilities take advantage of the lack of gravity that characterizes all of the central structures.

The radius of these cylindrical scientific research structures is 90 meters and the length is 400 meters.

4.4 Emergency Evacuation Center

A structure opposite to the Hangar is designed to hold large groups of people in case of an evacuation or if the rings need to stop spinning for major repairs, for example. This structure contains small living quarters and other necessary supplies for survival such as food and water. As viewed from the exterior, the evacuation center is a large, cylindrical structure with a radius of about 200 meters and length of 350 meters. Within the facility, there are many compartments for refugees to stay in if they have been evacuated from the rings.

4.5 Elevator Transfer Rooms and Elevator complex

The Elevator Transfer rooms are structures designed to solve the problem of transferring people and cargo from a non-rotating center to a rotating ring. Traditionally, designs including artificial gravity on a much smaller scale require the rotating ring to stop spinning if anyone or anything needs to travel from a center structure into the ring. However, in a design as large as this settlement, stopping the ring from spinning would cause chaos and disorder for thousands on board the settlement rings. Thus, the Elevator Transfer Rooms were devised to prevent the need for stopping the rings when cargo or personnel transfers from the center need to be made.

The Elevator Transfer Room is a cylindrical shaped structure that is designed to rotate independently within the axis of rotation for the rings. The rings rotate around a physical axel structure. However, this large axel is not continuous, meaning there is a gap between each half of the axel and in no place do these two halves actually connect. A smaller axel centered in the larger axel is what connects the two halves of the central structures of the settlement.

These images depict the primary components of the Elevator Transfer Room which include the large and small axel and the Elevator Transfer room contained within.

Within this newly created space, a cylindrical-shaped structure with a smaller diameter than the large axel is constructed and can rotate around the small axel. This cylindrical structure is the Elevator Transfer Room and it can rotate independently of the settlement’s rings. When personnel enter the Elevator Transfer or cargo is brought it, everything is secured and oriented in such a way that the soon-to-become floor is the outer surface of the cylinder. People will stand in small frames that they can hold onto. These frames aid a person in the orientation of his or her feet towards the outer surface of the cylinder. This is important because once the Elevator Transfer Room “spins up” to match the elevator shaft positions, a small artificial gravity will be generated in the Elevator Transfer Room and so a floor will exist.

The Elevator Transfer Room is initially not spinning. This allows personnel and cargo to float into the cylinder through hatches that will eventually retract so that the room can spin freely without obstructions. Once all personnel and/or cargo is loaded and properly oriented and secured, the hatches will close and the walkway will pull away from the cylinder to allow for spinning. The Elevator Transfer Room operators will then begin the spinning up process. The room will begin to rotate and a small artificial gravity will be generated. The openings in the Elevator room will then line up with the openings to the elevator shafts on the spinning rings. Laser tracking technology and position identification systems will assure that the openings are in fact lined up exactly. When this occurs, multiple telescoping passageways will extend and mate to their respective elevator shaft structure. The two sides will be secured and personnel and cargo can be transferred through passageways that lead into the root of each elevator shaft. Since all elevators are traveling down relative to what is considered the floor (the outer surfaces of the ring structures), all of the machinery, support lines, and motors will be constructed closest to the Elevator Transfer Room. Because of this, there are large passageways that bypass the machinery after all personnel and cargo has left the Elevator Transfer Room. After bypassing the machinery, personnel and cargo can enter individual elevators and travel “down” to the rings. As an elevator travels, artificial gravity will increase and people will feel heavier as the radius increases from the center.

There are four “spokes” that contain the personnel and cargo elevators. These “spokes” also act as structural support for the rings that are rotating. Within these “spokes” there are four individual elevators that can carry personnel and large cargo to and from the main rings. These elevators run on tracks and are lowered by cable. Cargo such as mined materials and goods can be transported in one of the pressurized elevators.

In total, there are four spokes protruding from the center of the settlement that are equidistantly spaced. This entire system (the Elevator Transfer Room, spokes, and elevators) is constructed twice on the settlement, making two Elevator complexes. Since the Elevators are so important to the function of the settlement, another entire complex is added for redundancy in case one Elevator Transfer Room experiences some sort of extreme failure.

The radius of the Elevator Transfer room is 15 meters. The width of the outer surface of the cylinder-shaped room is 20 meters. The Elevator Transfer Room is designed to hold about 772 people at maximum capacity based on a calculation that allocated 2.25 square meters per person. Cargo can also take the place of many people. The surface area of the outer surface of the Elevator Transfer Room is 1884.96 square meters. 147 square meters is dedicated to room operations and passageway opening/hatches; thus, 1737.96 square meters remains for personnel and cargo.

4.6 Ring complex Design

This image depicts the ring layout but does not portray the actual lattice-work ring structures

The rings make up the most populated areas of the settlement. Artificial gravity exists on the rings due to the rotation of the rings. This artificial gravity will be discussed in greater detail in the “Artificial Gravity” section. The rings are in reality frame structures that are shaped like rings. Within the gaps in these frame structures, separate components are installed. The term “components” refers to each individual structure and habitat that is constructed into the ring frames. The entire ring complex consists of two separate concentric ring frame structures and a segmented ring on the outermost level (the level with the largest radius from the center). The segmented ring consists are four separate parts that are equidistantly spaced around the circumference of the largest full ring structure. The decision was made to have multiple concentric rings because there was not enough surface area in a single ring to support the livelihoods of 10,000 people and 300 transient people. While the innermost ring frame is structurally attached to the center via the elevator shaft spokes, the next largest full ring and outermost segmented ring are attached through various structural support beams and within some of these connections, elevators used to transport personnel and cargo between rings are constructed. The innermost ring, the ring with the smallest radius, is the Business and Industry Ring. The next largest full ring is the Agriculture Ring. Finally, the outermost segmented ring is the Residential Level.

Business and Industry Ring

The Business and Industry ring is the ring with the smallest radius and it is the closest ring to the center of the settlement. It was decided that this ring would be dedicated to business and industry because it is directly connected to the various elevator shafts and it is closest to the center of the settlement, which is where all cargo and mined materials will arrive. This ring is dedicated to all forms of businesses including supermarkets, clothing stores, electronics stores, specialty item storms, and many other consumer good businesses. There are also businesses that are dedicated to larger-scale manufacturing and do not create normal consumer goods. Headquarter facilities for various utilities, public services, and systems such as water treatment and storage, electricity, life support, cargo management, transportation management, police headquarters, and fire protection headquarters, will all be located on this ring. All industrial manufacturing and raw materials processing will take place on this ring. This includes the manufacturing of goods, replacing parts for the settlement, and the processing of mined resources into usable materials such as metals. The large-scale factories, robotic equipment, furnaces, and mills will all be located on the Business and Industry Ring. Since this ring is the closest the center, it will be easier to transport large cargo to various businesses and manufacturing plants. The elevators coming from the center of the settlement are designed to carry large cargo; however, the elevators used to travel from ring to ring are smaller and are not designed to accommodate extremely large cargo. Also, Government facilities will be located on this ring. This is where the legislative house and the Executive do work. Finally, this ring will have certain “low-gravity” recreation and sports facilities so people can experience activities in slightly lower gravity. This occurs the rings spin at a rate to generate Earth’s gravity on the personnel ring, and since the Business and Industry Ring is closer to the center, artificial gravity will be slightly less. Components of various sizes will house businesses and various headquarter facilities. Larger components will be used for the manufacturing of goods and processing of raw materials. Within these components, multiple floors can be constructed in order to allocate space more efficiently.

Agriculture Ring

This ring frame structure is the next largest ring and has a larger radius compared to the Business and Industry ring. Access to and from this ring will occur via elevators around the entire ring that are large enough to accommodate personnel and moderately-sized cargo (most likely food products). This ring is entirely dedicated to agriculture and food growth. The ring’s components will be filled with irrigation systems, soil, and various crops. Multiple floors can be constructed within these components. Various vegetables, fruits, and grain products will be grown around the entire ring. The only other facilities that exist on this ring are several agricultural management facilities and packing/processing facilities. An entire ring had to be dedicated to agriculture because the surface area required to grow food for up to 10,300 people was too large to be combined with other facilities. The Agricultural Ring provides the nutrition and food that the entire population of the settlement needs in order to survive. This ring will have a slightly lower gravity compared to Earth which at most would result in less restricted water flow in various crops and plants.

This is a close-up view of one of the segments on the Residential Segmented Ring. Individual “home” components are visible

Residential Segmented Ring

The Residential Segmented Ring is the outermost structure, with the largest radius and it is the farthest structure from the center of the settlement. The Residential level is divided into four main segments that are evenly spaced around the circumference of the Agriculture Ring with gaps in between each segment. It was decided that the Residential level would not be an entire ring because significantly less surface area was needed to support 10,000 permanent residents and up to 300 transient visitors. The Residential Segmented Ring consists of components similar to a normal home on Earth. These homes range in size and some may consist of several floors while others are like apartments (smaller living spaces stacked on top of each other on numerous floors. The entire population of the ring will live on this part of the settlement when they are not working. In addition to home components, various recreational facilities, and community areas will be constructed. People can play sports, exercise, watch movies, or watch various musical concerts among other activities. There will also be components with larger open spaces with botanical gardens for families and friends to gather together and relax. In order to get to and from the Agricultural ring to the Residential Ring segments, elevators similar to the ones used to travel between the other rings are utilizes. These elevators can carry personnel and moderately-sized cargo. The Residential level was designed as the outermost structure because emergency escape via emergency lifeboat habitats requires a clear line of escape once ejected. Because they are located on the Personnel level, the lifeboats can leave the station without obstructions. Also, since artificial gravity just like Earth’s (with an acceleration of 9.8 m/2^2) is generated on the Personnel Level, any rings with a smaller radius will experience a slightly lower gravity. This is preferable to the Agriculture Ring and Business and Industry Ring having a larger radius than the Residential level, because if this were the case, those rings would experience higher gravity then Earth’s which is less beneficial for manufacturing and crop growth in which everything would be heavier.

This image depicts one slice of the frame structure. The three separate ring levels are also visible.

4.7 Ring Dimensions

The Business and Industry Ring, the innermost ring, has an inner radius of 2373.803 meters and an outer radius of 2476.803 meters. This space of 100 meters refers to the “height” within the components of that ring. There is a 100 meter gap between the outer surface of the Business and Industry Ring and the inner radius of the next ring, the Agriculture Ring. These rings are joined via elevator shafts and frame support structures in between. The Agriculture Ring has an inner radius of 2573.803 meters and an outer radius of 2673.803 meters. Again, this ring has an interior “height” of 100 meters. Between the Agriculture Ring and the outermost Residential segmented ring, there is a space of 100 meters. The inner radius of the Residential segmented ring is 2773.803 meters. The outer radius is 2873.803 meters. The width of each ring-frame structure is 2500 meters. The surface area of agricultural space necessary to support the population of the settlement is 42 square kilometers.. The Agriculture Ring is designed to meet this requirement. The segmented Residential ring needed to have a surface of 18.54 square kilometers at a minimum for living space; however, the actual surface area is larger to accommodate for recreational facilities and community areas. The length of each of the four segments on the Residential level is 2.75 kilometers with a width of 2.5 kilometers. The height is 100 m. The thickness of each frame cross-section that makes up each entire ring is 40 meters thick.

4.8 Artificial Gravity

Image from http://www.regentsprep.org/regents/physics/phys06/bartgrav/default.htm

Image credit: Science Joy Wagon

Artificial gravity is generated on board the main rings due to the spinning of these rings. Each ring follows a similar principle to the station depicted in the image. The outer “wall” of the ring exerts the normal force and “up” is towards the center of the ring (“Simulated Gravity with Centripetal Force,” 1998). While the ring-frames are not hollow and have many components, this principle still applies to each individual component on board the settlement. Using v^2/r, v being velocity in meters per second and r being radius in meters, the centripetal acceleration can be calculated. If that acceleration is set equal to Earth’s gravitational acceleration of 9.8 m/s^2, then the velocity required to achieve that desired gravity with any radius r can be calculated. At r= 2823.803 m, exactly in the middle of the Residential level, the velocity of the ring needs to be going 166.353 m/s in order to generate Earth’s gravity. The rings are ordered the way they are partly because the Business and Industry ring should be closest to the center of the settlement where all the cargo is arriving, the Agriculture Ring needs the largest surface area, and the Personnel Segmented Ring needs to be the outermost structure for safe emergency escapes via emergency lifeboats. However, the Business and Industry Ring and the Agriculture Ring have a smaller radius than the Residential Segmented Ring because they can have a slightly lower gravity than Earth’s instead of a larger one if the Residential Ring has the smallest radius. The Residential level is where “Earth’s gravity” is generated. The gravity experienced on the Agriculture Ring, in the middle, at a radius of 2623.803 meters is 9.106 m/s^2 using omega (angular frequency)=2pi/t where t is time and v=r(omega) to solve for the velocity at the given radius which is then used to solve for centripetal acceleration. Artificial gravity decreases as the radius decreases. Thus, as someone is traveling from a ring towards the center of the settlement in an elevator, their apparent weight will decrease since artificial gravity is decreasing and vice versa. Using similar calculations, the acceleration of artificial gravity on the Business and Industry Ring is 8.411 m/s^2. When the Elevator Transfer Room spins to match the speed of the outer rotating rings, it will only generate .052 m/s^2 of gravitational acceleration. As cargo and personnel travel out to the rings, they will become “heavier” since artificial gravity grows as radius increases. One rotation of the rings takes 106.66 seconds.

This image illustrates the orientation of a person who might be waking in a component structure on a ring. The person is walking on the “floor” and feels weight due to the artificial gravity being generated through rotation. The arrows show the direction of motion as the component spins.
In order to initially spin the settlement up to the speed that generates a gravitational acceleration of 9.8 m/s^2 on the Residential level, engines will be constructed into the outer Residential level and these engines can fire tangent to the circular shape. There will be two engines as part of each structure, one facing either direction so thrust can be provided in the clockwise or counter-clockwise direction in case various adjustments need to be made to the speed of rotation. This rotational maneuvering system will maintain the proper speed of rotation for the settlement.

4.9 Important Design Dimensions

Structure	Length (m)	Width (m)	Radius (m)	Height (m)	Surface Area (m^2)/(km^2)
Airlock	220 m	134.6 m	N/A	100 m	N/A
Hangar	800 m	650 m	N/A	550 m	N/A
Hangar Docking Beams	800 m	40.6 m	N/A	36 m	N/A
Scientific Research Structure	400 m	N/A	90 m	N/A	N/A
Evacuation Center	350 m	N/A	200 m	N/A	N/A
Elevator Transfer Room	N/A	20 m (Outer surface)	15 m	N/A	1884.96 m^2 (outer surface including non-storage areas)
Business and Industry Ring	N/A	2500 m (outer surface)	Inner radius: 2373.803 m Outer radius: 2476.803 m	100 m (from “floor” to ceiling”)	38.905 km^2 (outer surface)
Agriculture Ring	N/A	2500 m (outer surface)	Inner radius: 2573.803 m Outer radius: 2673.803 m	100 m (from “floor” to ceiling”)	42 km^2 (outer surface)
Residential Ring (values apply to one segment)	2750 m	2500 m (outer surface)	Inner radius: 2773.803 m Outer radius: 2873.803 m	100 m (from “floor” to ceiling”)	6.875 km^2 (outer surface)

4.9.1 Propulsion and Orbit Maintenance

Over time, the orbit of Ender around the sun might change due to long-term exposure to the solar wind (Ender’s large surface area could turn it into a solar sail), occasional impacts from small space debris, or avoidance maneuvers to steer clear of larger space debris. To maintain the orbit of Ender around the sun and its placement at L2, small reaction control system (RCS) thrusters will adjust Ender’s position. Several thrusters will be placed around the circumference of the agricultural and residential rings, as well as on the upper and lower surfaces of the rings. The thrusters will be angled in varying directions to give Ender maximum mobility if it needed to avoid a piece of space debris on short notice.

To start Ender’s rotation to induce artificial gravity, ion thrusters will be placed on the outer circumference of the spacecraft. Each thruster will have the capability to point in opposite directions to control the rotation rate of Ender. Ion drives will be used because of the ability to apply low amounts of force over long periods of time. The rotation rate will be easy to adjust using this system, and changes in the rotation rate (if ever necessary) will be so gradual that they will not be noticed by residents.

5.0 Public Works and Environmental Control and Life Support Systems (ECLSS)

Public works and ECLSS infrastructure is critical to Ender’s success. Many of the same civil infrastructure systems here on Earth will be necessary aboard Ender.