: CIRCULAR TRACKS AS SPACE SETTLEMENT
SpaceX Starship and The Von Braun Rotating Space Station
The Von Braun rotating space station will be the first commercial space construction project in history. It will be serviced by the SpaceX Starship and be designed to accommodate national space agency laboratories, billionaires who want to own property in space, and space tourists. Please visit our website at www.gatewayspaceport.com/membership
Credit: The Gateway Foundation
CIRCULAR TRACKS AS SPACE SETTLEMENT
Unlike a torus shell or tunnel that can be used to protect an HGV that uses a Transfer Vehicle, a different shell design is required for the optional shell for a Hub-and-Spoke ESHGF. (as see above)This shell design can use a stadium roofing material. However, unlike stadiums, this ESHGF shell uses a stationary 45m tower at the center of the ESHGF hub, essentially acting as the axle that the hub ring rotates around, but also is used to support the roof.
The Hub-and-Spoke subsystem (below)can also support multiple HGVs in concentric rings. An ESHGF with multiple rings has the advantages of increasing capacity as well as providing an increased variance in hypergravity and rotation radii to better characterize their different effects.
The above figure depicts three concentric HGVs consisting of a total of 72 HGVCs, each with 26 cabins. The total cabin deck area of this configuration is 96,768m2 (1,041,601ft2). This supports a population of 3,456 at cruise ship density.
ESHGF Incremental Implementation with 26-Cabin HGVCs in ‘X’ Configuration Top View
Implementations: 4-HGVC (top), 12-HGVC (middle), 34-HGVC (bottom))
ESHGF Incremental Implementation with 26-Cabin HGVCs in ‘I’ Configuration Top View / Implementations: 2-HGVC (top), 10-HGVC (bottom)
ESHGF Incremental Implementation with 26-Cabin HGVCs in ‘Y’ Configuration Top View
Implementations: 3-HGVC (top), 15-HGVC (bottom)
The Extended-Stay Hyper Gravity Facility (ESHGF) is essentially the merger of two technologies: centrifuges and trains, in which an extremely long-arm centrifuge is created using vehicles similar to tilting trains.
The concept is essentially a train on a circular track designed to generate a specific, long-duration hypergravity level for humans.
We see in the below figure that the HyperGravity Vehicle (HGV) subsystem is an electric train consisting of a sequence of connected cars running on a track. People will be able to move between cars as they can onboard a typical train. The general design is for all HGV Cars (HGVC)s to be the same size, but custom-size cars can be accommodated.
The interior of each car is expected to be customized to meet the needs of its occupants and manager. Car types are expected to include at a minimum living quarters and workspace. Other car types may include dining facilities, farms, aquariums, pools, arboretums, botanic gardens, factories, gyms, sports center, markets, meeting rooms, etc.
The three major elements of each HGVC: Cabin, Chassis, and Cabin Tilt Mechanism.
The above figure show an HGVC with a 24 x 4 x 4m cabin on a 300m diameter 30° super elevated (banked) track with an additional Cabin Pivot Angle of 30°.
HGVC Tilted Cabin on Track
HGVC Cabin Tilt Mechanism Subsystem
HGVC Tilt Mechanism Subsystem - ; blue arrows show rotations when pivoting to the right
Each HGVC have the capability to control the tilt of its cabin in respect of its hypergravity vector. To do so, the HGVC tilt mechanism subsystem control actively the tilt of the cabin.
A special feature of each HGVC is its capability to control the tilt of its cabin so that it is relatively level with respect to its hyper gravity vector. The HGCV tilt mechanism subsystem enables this capability by actively controlling the tilt of the cabin with respect to the chassis depending on the velocity of the HGVC.
Une particularité de chaque HGVC est sa capacité à contrôler l'inclinaison de sa cabine afin qu'elle soit relativement plane par rapport à son vecteur d'hyper gravité. Le sous-système de mécanisme d’inclinaison HGCV permet à cette capacité en contrôlant activement l’inclinaison de la cabine par rapport au châssis en fonction de la vitesse du HGVC.
The electric tilt motor and its servo controller precisely control tilting the cabin to the commanded angle. The commanded angle is a function of the HGV velocity and the track (chassis) super elevation angle.
The HGVC Cabin Tilt Mechanism attaches the HGVC cabin and chassis by means of two pivot structures and four scissor jacks. The scissor jacks are used to change the tilt of the cabin with respect to the chassis. A triple transaxle is used to transfer the input torque from the electric tilt servo motor to the four threaded rods of the scissor jacks. The triple transaxle outputs torque such that as the left jacks are raised, the right jacks are simultaneously lowered.
The tracks and the HGV chassis can be designed to support the loads as needed. In most cases, the 4-rail track described in this design concept should be sufficient. The HGVC design specifies 10 wheels per wheel truck and 2 wheel trucks per chassis . To provide context, cargo trains are currently operational that support 40,000kg per 2-wheel axle.
The HyperGravity Vehicle Cars (HGVCs) operating on a track at 3.2 RPM, generate 1.97g. At a lower RPM, the Cabin Pivot Angle is less with a corresponding lower hyper gravity level. HGVC stability design considerations to compensate for such a steeply super elevated track and HGVCs with high pivot angles.
26-Cabin HGVC on Track Perspective View Stopped (left) and at 2g orientation (right)
HGVC STABILITY DESIGN CONSIDERATIONS
The primary HGVC stability issue that must be addressed is atypical for trains and is due to the high side loads, and in some cases negative loads, on the HGVC wheels and tracks which could lead to an HGVC derailing and tipping over if not engineered properly.
These loads are due to the steep track super elevation angle (30°), the tight turn radius (150m), the high speeds (112mph), the pivoting cabins (+-30°), the shifting cargo and passengers, and the high cabin surface area subject to winds (if the ESHGF is not enclosed).
In this design, the risk of derailment is mitigated by the HGVC horizontal and vertical wheels on the chassis wheel trucks that ride on three sides of the tubular-track side rails.
VEHICLE TRACK SUBSYSTEM
The Vehicle Track subsystem is the pathway for the HGV and Transfer Vehicle and provides electricity to both subsystems. Both tracks are super elevated and circular.
ESHGF System depicted in a HGV complete ring configuration - The HGVCs must be spaced with sufficient margin between cabins to prevent contact between cabins when tilted.
Transfer Vehicle Docking with HGVCs Rear Views in Max g Orientation (left) and Stopped Orientation (right)
As depicted in both figures, a shell may be used to cover the track, HGV, and Transfer Vehicle to protect them from the weather and provide security.
Transfer Vehicle Side Views Cabin Elevator Raised (left) and Lowered (right)
The track foundation is implemented with a reinforced steel and concrete ring to minimize track deformation over time, but could also be implemented in a bedrock tunnel.
An optional augmentation to the track design concept presented is for the tracks to support maglev cars to minimize their energy use, noise, vibration, and wear. At low speeds and in emergency cases the vehicle wheels would contact the tracks, but during nominal operations the vehicles do not contact the tracks other than for power. Once the HGV reaches a significant operating speed, the passengers will not easily detect that the cars are moving. However, they will be able to detect their bodyweights and cabin content weights have increased.
HGVC CABIN SUBSYSTEM
The nominal cabin sizes are 4m wide, 4m high, and either 12m or 24m long. These sizes were selected due to their similarity to train car sizes and their feasibility as analogues for off Earth use.
A space-rated version of this cabin could be accommodated as a payload on a heavy-lift launch vehicle for use on orbit, in the Moon, in Mars, in the Mars' moons. and in asteroids.
Above, the top View of an HGVC 6-room Cabin Floor
Each HGVC has a cabin with a hall that can connect to an adjacent HGVC cabin for people and cargo to travel the length of the entire HGV. This figure depicts a 6-room floor plan. However, the floor plans are flexible because internal cabin walls are not load bearing and may be moved.
A key feature of the ESHGF is its modularity. Each module, comparable to intermodal shipping containers, can be transported by rail, truck, ship, and aircraft as shipping containers currently are transported. The size of these modules are also feasible for heavy lift launch vehicles. If necessary, the ESHGF Cars and/or Modular Cabins can be separated, transported, and reattached at their destination. Also, ESHGF cabins and cars can be added as needed to increase system capacity, as well as be removed for maintenance, to be upgraded, or replaced with modules tailored for different purposes.
HGVC CABIN GRAVITY MAP
Ideally, the hypergravity level would be equal and constant for all points in a HGVC cabin for the gravity, like the way people are accustomed to on Earth. However, there will be minor gravity variations at different points in the cabin. In fact, at different distances from the center of the HGV track circle, we have different centripetal accelerations and corresponding hypergravity levels.
HGVC cabin 24 x 4m Floor Hypergravity Map showing microgravity variations
Pertinent parameters for this example are the HGVC cabin coordinates (x, y), the Cabin Pivot Angle = 17.6°, the track radius = 150m, the HGV velocity = 40m/s, track superelevation angle = 30°, Cabin Pivot Center height = 1m, Cabin floor height from pivot axle center = 0.5m, Cabin length = 24m, Cabin width = 4m, front & rear wheel truck offset = 3m, and ambient gravity = 9.807m/s2 (Earth)
The use of a large radius track minimize these variances.
This hypergravity map varies with different HGV configurations and velocities, but in most cases the basic characteristics are similar. Then, it varies with the (x, y, z) position of an object in the HGV cabin.
The lowest-hypergravity point on the cabin floor is in the middle of the cabin where the floor meets the inner wall, i.e., position (0, -2). At this position, the hypergravity is 1.464g's, so a 1kg mass would weigh 1.464kg.
However, the hypergravity at both outer corners, positions (-12, 2) & (12, 2), is 1.481g's, so a 1kg mass at both of those locations would weigh 1.481kg, 17 grams more, an increase of ~1%. In most cases, a variation of 1% would not be noticeable, but the hypergravity map is a design consideration. This variation increases considerably on smaller diameter tracks.
Although the floor is flat, water would tend to flow and balls would tend to roll away from the inside center to the outside corners of the cabins, with an asymmetric bias toward the rear outside corner since any object moving away from the track circle center will gain momentum in the process. This variance is less within each cabin room since they are smaller.
The length, width, and height of the HGVC cabin all impact these hypergravity variations. A person moving directly across a cabin from its outside wall to its inside wall also moves further toward the center of the track circle and reduces the person's rotation radius. By increasing the sum of the track superelevation angle and cabin pitch angle to 90° such that the cabin floor is perpendicular to the track plane, a change in width position will no longer cause a change in hypergravity. However, such a configuration is only appropriate in a low-gravity environment such as an on-orbit or on an asteroid. Reducing the width of the HGVC cabin will also reduce this variance, but this also can be accomplished by creating narrower rooms within the HGVCs as needed.
Since the cabins are straight instead of arced with the same radius as the track, moving toward the lengthwise center of a cabin also moves further toward the center of the track and reduces the spin radius (each cabin lengthwise centerline is a chord of the track circle – see Figs. 15 and 33). This variance can be mitigated by arcing the floor and shortening the HGVC cabin length or cabin room lengths if necessary.
The hypergravity level of an object decreases as it is raised in the cabin, e.g., an object on a table in the cabin will weigh less than the same object on the floor directly below it (with respect to the Cabin coordinate frame). Since the cabin is tilted toward the track circle center, increasing the height of an object decreases its track circle radius and its corresponding centripetal acceleration.