As has been explained in other articles, human activity in large open spaces within larger microgravity habitats presents a variety of complications. While various forms of free-moving microgravity vehicles may be possible, these will require considerable technological sophistication, stored propellants and electric power, and some degree of skill to operate. Much simpler technologies are likely to be needed for more routine activity in these spaces, particularly in earlier stages of Asgard settlement.
Some of the simplest, lowest mass, and most rapidly deployable of all long-span transit devices are gravity-based ‘zip lines’, cable cars, and wire monorails. Given the long history of use of such devices in industrial and construction applications, similar devices would seem a logical addition to the repertoire of habitat construction tools. Cable-car-like systems, based on moving loops of cable driven by electric motors at one end, are a quite likely initial innovation. But these systems have traditionally required rather bulky end-station components and without gravity to stabilize and separate payloads along the alternately moving cable lines, collisions and tangling are possible, requiring rather wide spacing between cables and the use of additional passive guide lines that stabilize payload motion during towing. A more ideal system would employ static lines and shuttle devices with their own motive power. This too would be a likely innovation, however, here too one faces complications from the use of friction drive systems which are slow, require a shuttle device to be equipped with a motor and stored power, and with cables being under constant wear with use. A better technology would eliminate the need for a bulky motor unit and power source on a shuttle device using the cable as a power conduit, reducing shuttle scale and mass, and would eliminate wear on the cable by using a minimal-friction means of motive power. Anticipating these needs, we arrive at a concept called the ZipLine.
Based on a multi-core composite tether made of alloys and carbon fiber and various small shuttle units that clamp a two-piece tubular unit around the tether, the ZipLine Tether Transport System would essentially be a form of linear motor driven by power conveyed along the tether. Shuttle drive units would consist of a two-piece tubular unit forming one half of the linear motor drive, the tether itself the other half. Polyurethane bearings or Teflon slip-rings would maintain spacing of the drive when not moving, though when active the unit would be magnetically isolated and magnetically resist axial rotation. These drive units would feature a latch to open and release them from the tether like a C-clamp and a modular connector to which various forms of payload attachment would be mounted.
The basic shuttle form would consist of an alloy loop, similar to that used on some subway car hand-holds, combining foam rubber grip, thumb control triggers, and a carabineer to which a man-line safety tether and small bags or satchels can be attached. Intended as simple individual transport, this unit would be operated by gripping the hand-hold and pressing a trigger with the thumb, light contact on the trigger maintaining the ‘on’ position and releasing it causing the unit to (magnetic regenerative) brake and stop. Likewise, any release of the grip on the hand-hold would also cause it to brake and stop. When activated, the units would slowly ramp-up to a cruising speed and slowly brake when approaching the ends of the tether to avoid jarring accelerations and decelerations. Thumb switches on alternate sides of the hand-hold determine the direction of travel. Though a simple device, the shuttle units would have enough built-in intelligence to sense the distance between other shuttles on the tether and could brake and stop autonomously to avoid collisions.
An automated form of this basic shuttle unit would combine the shuttle with a cluster of carabineers and a simple push-button control pallet. These would be designed to carry small payload satchels and run from one end of the tether to the other automatically, starting after a short count-down (marked by light and tone) from control pallet activation. The unit would travel continuously to one tether end and stop or would reverse if it encounters an obstruction. Rigid spacer tubes would allow the shuttle drive units to be combined to form larger forms of this same automated unit, allowing for multiple attachment points for payload containers. The largest of these might employ a rigid radial payload basket or a gridded cargo pallet panel similar to that used by the previously described Carrier Pallet.
Another human-transport form would follow suit. This would use a radial array of two or three rigid harnesses around an extended shuttle set. The harness would consist of shoulder, foot, and thigh braces around a back pad which one slips into in a standing position. An armrest then provides the usual controls and additional carabineers and gridded cargo pallets between the harnesses provide safety line and small cargo attachment. Usable in either travel direction, the harnesses would be reversible to allow use in the preferred feet-forward mode for more comfortable deceleration.
Systems of multiple ZipLine tethers, in groups of two, three, or more, may be employed to create heavy payload handling systems or used for permanent transit units based on larger carriages with edge-mounted drive units. Generally, though, the ZipLine is most likely to have a role limited to temporary, quickly moved, installations during construction activities.
ZipLine systems would also be usable in the ambient space environment and this may be one of their most important applications during construction activities. Pressurized transfer capsules would employ a simple design based on a small cylindrical capsule (with padded interior for passengers) with end hatches paired to an external life support chassis and would work with single or multiple tether ZipLines. But, generally, most passenger uses of this system would likely employ the very same forms of other manned ZipLine carriers, operated by suited astronauts.
- Urban Tree Housing Concepts
- Asgard Digitial Infrastructure
- Carrier Pallets
- WristRocket Personal Mobility Unit
- RocShaw Personal Mobility Units
- Pallet Truck
- MagTrack Transport System
- SkyGarden and SkyFarm Systems
- Meat Culturing
- Microgravity Food Processors
- Pools and Baths in Orbit
- Solar Sails
- Plasma and Fusion Propulsion