The SE Downstation is the Earth-based portion of a Space Elevator system. We will be discussing the Aquarian Space Elevator in more detail in the section on the Brofrost space program. Here we will discuss the Downstation facility itself and how it will evolve and relate to the other transportation systems used by Aquarius colonies.
The first Space Elevator system deployed as part of TMP is likely to be a rudimentary system based on a single nanofiber ribbon of only tens of centimeters width and using either a completely independent platform for its Downstation facility or a similar extension platform located at the perimeter of an existing colony. Using simple ribbon climber robots powered by projected energy, the initial SE would present a very long transit time and be limited to small but diverse payloads, many of which may include hazardous materials in relatively small volumes. Unable to provide for manned transportation, it would support a Modular Unmanned Orbital Laboratory – MUOL type teleoperated facility at GEO.
The initial Downstation would employ a generally radial structure up to three storeys high which the SE ribbon enters from the center top. This Downstation would consist of an Anchor Well which hosts spools for the ribbon topped by a Service Atrium with an optional top closure which features a series of radial Payload Processing Bays, a Control and Monitoring Station, and several Climber Service Bays. These bays could be up to three storeys high while, behind them, space may divide into individual floor levels, perhaps in the usual concentric terrace approach used in most Aquarian architecture thus assuming a form rather like a circular ziggurat. A Climber Carrier vehicle –basically a modified fork-lift or scissor lift– would move within the atrium and ‘launch’ the climbers by supporting them as they engage the ribbon, which would always be in some degree of modest up and down motion. Power for the climbers would be based on a two-stage system, the Climber Carrier charging a set of super-capacitors on the climber by direct connection to get the climber up and out of the Service Atrium. Then primary power projectors mounted on the top roof of the Downstation or at stations around the Downastation main structure would lock on the climber to provide power on its long trip to orbit. Radio transceivers communicating with the climber and the GEO Upstation would also be mounted on the main structure roof.
Since the initial Upstation facility would only serve as a research facility, its transit needs would be intermittent and the Downstation facility would do adequately with either fairly basic terrestrial transportation support or by relying on the transit systems hosted by its parent marine settlement. For a mature colony, this could be as simple as a single PRT link akin to that of any perimeter-located industrial facility. For a more independent facility, cargo handling would be more rudimentary using helipads and a perimeter ‘quayside’ docking area which, for a simple rectilinear two-deck PSP platform, would allow ships to dock temporarily on the leeward sides of the facility.
A minimum PSP platform is a ‘two deck’ structure. It has a ‘base deck’ with a two or three storey high space directly atop the PSP cell structure that is used for platform support equipment like the station-keeping motors, power systems, water and waste processing, and cargo storage. This is topped and enclosed by a ‘main deck’ that serves as the primary level everything else is built on. For the SE Downstation the base deck would be the location of the Anchor Well with the Service Atrium set at the level of the main deck. By leaving an edge of the base deck open and exposed by a recessed portion of the main deck one creates a ‘quayside’ that can be used for docking ships and can host container-handling lifts, deployable ramps, cranes, transfer cable winches, and other equipment.
Obviously, a Downstation that starts integrated to a colony will have much less need for space as it needs none of the equipment and storage self-sufficiency on the open ocean demands and because its work activities are likely to be spread widely about a colony rather than concentrated solely around the Downstation. The independent Downstation is likely to need much space just for power generation –particularly if it relies on OTEC or other forms of solar power.
The likely pattern of evolution in expansion for a Space Elevator begins with a single ribbon and moves to a close-spaced ribbon array, to laminate thickening of ribbons, to a corrugated tether. Following this pattern the next likely form of the Downstation would be organized in the same way but larger in area. The Service Atrium would host several SE ribbons in the same space and be surrounded by a larger set of service bays on possibly several levels. As the MUOL Upstation evolves into a Modular Unmanned Orbital Factory – MUOF facility, the Payload Processing Bays would become continually leased spaces accompanied by leased workshop and office space both around the Downstation and on the host marine colony. At this stage it is more likely that any independent Downstation platform would be integrated to the periphery of some colony, exploiting its more robust transportation capabilities, exploiting its space for industrial and office facilities, while still having some smaller independent facilities for ships and aircraft that are handling more hazardous materials.
The basic point to moving to a ribbon array is maintaining continuous SE operation while it is physically maintained and expanded. The process of repairing or upgrading an individual ribbon would leave that ribbon unusable for months to years. An orbital facility may not be maintainable with such a long delay between its own service. So by using multiple ribbons one not only increases the transit bandwidth of the system, one insures continuous operation while the system is maintained and expanded. This may call for more sophisticated payload and climber vehicle handling in the Service Atrium, perhaps resulting in the deployment of a climber service robot physically integrated into the structure of the atrium and other portions of the Downstation as if it were an automated materials handling facility. Since the shift to a ribbon array would likely begin a process of ribbon upgrade to support larger capacities and faster climbers, the Service Atrium and its carrier robots will need to support progressively larger and more complex climber vehicles and heavier payloads.
As the SE evolves into a corrugated tether structure, radical changes in the structure of the Downstation would become necessary to accommodate a very different form of transportation on the tether as well as to support what may become, by this time, a manned GEO Upstation facility for which the tether becomes a primary structural element. Evolution of the SE to a corrugated tether –an array of channels– would be predicated on the same premise that drove it to use multiple ribbons; the ability to maintain continuous operation while perpetually upgrading and maintaining the SE structure. At this stage this maintenance and upgrade work may involve the use of in-situ nanofabrication of some kind, which would employ more specialized climber robots that must work on the structure over very protracted periods of time. Most of this work may be conducted externally, leaving the inner channels free for transit use.
The channeled structure also allows for the use of linear motor driven elevators capable of great speed and for the use of channels as power conduits in the form of waveguides, improving the efficiency and capacity of power communication and allowing for bi-directional communication. All this means a vastly improved capacity and rate of transit and eventually the capability to support routine human passenger traffic. But the structure of the service facilities at both Upstation and Downstation would be very different.
Because of this new tether structure, terminal points along the tether must be ‘exploded’ to allow channels to be exposed to access. What this means is that, if one can imagine the tether as being like a woven rope, one is ‘bunching up’ or ‘stretching out’ the individual strands of the rope to expose the interior while still keeping all the strands intact. Thus at the Downstation the terminus of the tether would spread out like the roots of a tree as a concentric series of channels are exposed for access at different levels, the lowest level accessing the deepest core channels. Where each channel is ‘opened up’ an inserted space frame structure provides a short space of linear motor track for the elevator cars that are loaded or accessed sideways in the channel. These cars may ultimately become quite large –perhaps as large as 6 meters wide and 15 meters long– with most being based on light open space frame chassis while those carrying passengers would be completely self-contained spacecraft, likely combining a space frame chassis with a membrane pressure skin like a TransHab module.
Now having to host such a sophisticated transit system, the Downstation may become a very large structure akin to the ‘mountain form’ structures of the main colony in both shape and scale that appears to flare out from the base of the SE tether penetrating through its peak. This is likely to be so large that it would assume the form of a fairly large extension of the basic shape of the colony, its own air and marine transit terminals radiating along its portion of the colony perimeter. There would still be a Service Atrium but it would now be a vast many-storey enclosed space as large as the ‘core atriums’ of major mountain forms of the colony and which would host the complex gantry frame structures accessing and shuttling the progressively large elevator vehicles between large level bays. A second smaller Service Atrium at the top of the structure would host only external climber robots, which would most likely employ a series of narrow open channels in the tether surface as a track and may still rely on externally projected energy. This is likely to be accompanied by an external tourism elevator with a small passenger terminal which, though unable to travel to orbit, would offer passengers the thrill of a ride to the stratosphere with large window views –something those going to orbit would, unfortunately not enjoy. Both large industrial cargo and passenger service facilities would need to be integrated into the Downstation, the passenger facilities being akin to those of an air terminal, though it is likely that even at this large scale only one to a few core-most elevators would actually be used for passenger transit. While the intermediate stages of the SE Downstation may have integrated some early industrial production facilities in support of MUOF operations, by this time the Downstation would be very dedicated to transit and payload processing and so these kinds of facilities would be moved to other portions of a colony.
At it’s largest scale, the Aquarian SE Downstation may become the single largest and most central structure in the marine colony, the tether a vast diamondoid conduit that makes the whole colony appear like the foot of an impossibly tall tree with dozens of channels supporting these large elevator vehicles and conveying massive volumes of people and goods between the sea and a GEO Asgard colony of equally impressive scale. We’ll be discussing the design of that orbital colony later.
- Solar Ferry
- Solar Wingsail Cruiser
- Relay Archipelago
- Aquarian Airship
- Aquarian Personal Rapid Transit System
- Aquarian Personal Packet Transit and SuperStore
- Circum-Equatorial Transit Network