This feature is the existence of Bridges, which are portable "wormholes" in space-time.
In the game's setting, a company named BridgeCo invented these in 2020. The company kept their existence secret until 2070. During the intervening 50 years, BridgeCo has explored fairly thoroughly a sphere of radius 50 light-years, using unmanned factory ships that are self-replicating as well as creating a "bridge network" that links any notable planet or other resource. The gameplay happens during the following decade, as BridgeCo severs its ties with Earth, takes with it the Earth's bravest and brightest, and oversees the initial colonization of space.
Just because the game setting says so, Bridges work as follows:
- They must be built as a "Bridge Pair": two closed, adjacent, matching loops of metal and circuity. Activating them requires a lot of energy, and destroys most of their internal parts.
- After activation the loops act as a portal with no space in between them. (The "back side" of each Bridge in the pair also is a portal, but usually this is covered over.)
- Activated Bridges are metal objects and fairly sturdy, but can be broken. If they break the portal closes. There is no release of energy when a Bridge is destroyed or its portal closed (big deal, you have filled in a hole of no depth).
- Activated Bridges can be translated in space-time, but not rotated. (For example, if a Bridge is facing down into a gravity well, such as face-down on a planet, you cannot pivot it upright.) Trying too hard to rotate a Bridge will break it.
- Bridges may be moved through Bridges. Some applications even involve "Bridge Stairs" in which a small Bridge is carried in a sphere that allows it to rotate, and out of this Bridge slides a very long, narrow, rectangular Bridge, and out of that slides a very long, square Bridge. (For example, a spherical locket can contain a system of three portals with the largest big enough to transport a spaceship.)
- Only BridgeCo knows how to build Bridges. The setting has alien races and alien technology, and all existing Bridges incorporate alien technology in ways that make reverse-engineering Bridges currently impossible to anyone outside of BridgeCo.
- Both BridgeCo and other people know how to make gravitational anomoly detectors, of which even portable models can accurately detect Bridges at a range of several miles.
- BridgeCo has access to more than enough physical resources, of any type, for everyone. Currency would be based on worker-hours, the only commodity of which BridgeCo has demand. Other companies and organizations would purchase vital resources from BridgeCo until they are part of self-sufficient colonies. Even after self-sufficiency has been achieved, except for specialty resources (i.e., a chemical derived from a plant or animal found only on a non-BridgeCo planet, pancake syrup made from the sap of your colony's special tree) there is no normal reason any resource would be sold for more or less than BridgeCo's price.
- For electrical power, build solar panels in orbit around a star, and run the output wires through a Bridge pair to where you need the electricity. The only disadvantages are that the star might act up, or a troublemaker with an electron telescope can detect your device from light years away.
- For mechanical power, activate a Bridge pair and then seal shut its portal in a manner that would destroy the Bridges to undo. Now it will conduct heat but not matter. Put one Bridge on an appropriately hot planet, or in an appropriately hot orbit. Put the other in the tank of a steam engine. As before, you have power until the distant Bridge is destroyed. This setup is only detectable by troublemakers at a range of several miles. (BridgeCo sells these in several standard sizes as "Eternal Engines".)
- If you want to travel planetside, use rotor-powered vehicles. Helicopters and fan-powered "cars" are both very practical if energy efficiency and fuel weight are not issues. Colonized planets in this setting would not have roads.
- To travel between a planet and its satellites, any fan-powered vehicle need simply be reasonably airtight, have multiple turbines, and use Bridges to at the entrance and exit of each turbine to direct airflow so there is a net push. (In space, a ship can move simply by being a paddle boat that carries its own river of air.) Bridges also mean that spaceships need not worry about life support systems or radiating heat.
- Few manned vehicles would be built capable of traveling between planets, let alone between solar systems. (Putting it another way, there would be many "shuttles" but very few "spaceships.)
- Bridge routes need monitoring and security. Planets would want all off-planet Bridge travel arriving at a hub before possible travel planetside. (Thus "ports" become way-stations on moons or space stations.) The concept of a "mega-store" is changed . (For example, except for security there is no longer a practical difference between a huge mega-store and a collection of smaller stores linked by a Bridge network. Thus large corporations have incentive to own and run a planet. Unless you live someplace that has local food for sale, why shop or work at a small, neighborhood market when MegaMarket is equally close and manages security for their own planet?)
- Unactivated Bridge pairs are potential weapons. Even by themselves they could be used to siphon away air or create a flood. Dropping a bomb (conventional or nuclear) through a Bridge pair would be a safe way to attack something, since the Bridges would be destroyed before too much of the explosion entered the attacker's side of the portal.
- Rumors that Bridges are physically thick because each Bridge is actually two Bridges (in other words, BridgeCo builds "back doors" into each Bridge) are, of course, completely false. (Wink, wink.)
UPDATE: The reason Bridges cannot rotate is to prevent them from being used within weapons. I don't want a small-looking gun magazine that holds a nearly inexhaustible supply of cartridges, a short-looking gun barrel that is actually a long rifle barrel, or a sword pommel from which springs a long blade.
