The Technology Database

[Mlle Bienvenu]

Game Tech Goes Here

[Big Brother]

Tunnel Drive propsed FTL technology

Tunnel Drive is a method of getting around the speed-of-light limitation on interstellar travel without actually breaking the speed of light.

As many of you may be aware, Gravity is now understood to actually be a bending of the fabric of spacetime. A large mass such as a sun or black hole bends space around it, sort of like a heavy weight placed on a trampoline makes a dimple in the surface.


Gravity well showing the bending of light paths to
change the apparent position of a background star

Tunnel drive takes advantage of the bending and stretching of the fabric of spacetime in the vicinity of large masses such as stars. A ship with a tunnel drive can go into a sort of slingshot trajectory to closely approach a star, and at the appropriate microsecond when it is headed in exactly the correct direction, it uses a powerful energy discharge to punch a hole in the weakened fabric of spacetime along the slope of the gravity well.



As Fig. 1 shows, once it has punched through the wall of the gravity well, a tunnel drive ship enters "deadspace", a parallel dimension. This dimension has nearly no mass in it, and is on a different "time" axis to our own, but otherwise has a point-to-point correspondance with our own universe. Wherever there is a sufficiently deep gravity well in our universe, there is a slight "buckle" in the spacetime fabric of this parallel dimension as well. These buckles are the only effective means of navigating in deadspace, aside from inertial and dead-reckoning methods.

Once a tunnel drive ship reaches the "buckle" corresponding to the destination star, it punches another hole through the weakened fabric of spacetime and re-enters our home universe. A high degree of navigational precision is needed for both the initial insertion into deadspace and the eventual return to normal space, both to avoid crashing into the sun at the center of the gravity well in question, and to ensure a proper course once in deadspace. If a ship does not end up aimed almost directly at the buckle of the destination star, it may not be able to find it, as gravitic sensors are of somewhat limited range for steady signals (gravitic waves from moving or pulsating objects can be detected from much further away).

Deadspace is almost completely empty, aside from some stray hydrogen atoms that tend to collect into small nebulae or brown dwarf stars around the buckles of gravity well protrusions from our universe. So why would anyone want to go there? Because it is on a different time axis from our own universe, and time duration experienced there does not count towards time in our own universe. Any ship that returns to normal space from deadspace, no matter how long it felt it was away, returns to the exact microsecond it left.

This allows space travelers to cheat a bit. Instead of putting themselves in cold sleep for the decades-long journey from star to star at sublight velocities, arriving so long after they left that any return home to the world they left behind is rendered impossible by the inevitable march of time and progress, by traveling through deadspace, the long time needed for the journey is experienced on a different time axis and thus does not "count".

Of course, they still must experience the time needed to travel at sublight velocities, but by traveling in the hibernation of cold sleep, passengers from most species do not appreciably age. They can go to sleep shortly after entering deadspace, awaken shortly before returning to normal space, and sleep away the decades of their journey and return to our own universe the very microsecond they left it, but at their destination star.

[Big Brother]

Economic and Political Implications of the Tunnel Drive

Astro-navigational and cartographic precision is vital in use of the tunnel drive. Ships that enter deadspace with the wrong initial course may miss the buckle at their destination star and not have sufficient fuel to turn around and search for it. This severely limits the distance that can be traveled in one trip, because the farther apart two stars are, the harder it is to have the necessary level of precision in plotting a course, and the more time there is during the journey for tiny errors to be magnified. Since none of the gravity buckles in deadspace have attracted enough of the sparse matter in that dimension to produce a self-luminous star, it is practically impossible to see your destination from far enough away to plot course corrections if needed.

Therefore, it is vital to have proper navigational and astrometric data from our universe to plot a correct course before entering deadspace. Long journeys are not undertaken directly from one star to another, but rather, ships must make their journey in several stages via stars in between their origin and destination. Trips of longer than about 10 light years require multiple stages rather than one journey. Thus, even star systems with no inhabitable planets become important as way stations and stopping points between more valuable or interesting star systems.

One possible implication is that perhaps the reason all our player races came to the Sol system in a short period of time is that it was just recently mapped and added to the database of tunnel drive destinations, and a presence was required here in order to allow travel past Sol to more interesting nearby systems, such as perhaps Barnard's Star, Tau Ceti, or Alpha Centauri.

The need to keep ships entering and exiting deadspace from trying to be in the same place at the same time and thus colliding, plus the need to keep up-to-date astrocartographic data for navigational purposes, mean that each star used as a tunnel drive waypoint will need a local space station in close orbit around that star to serve as traffic control. These space stations also serve as refueling stops for ships that probably burn most of their fuel accellerating and decellerating in deadspace so they have enough reaction mass to climb out of the gravity well of the star and reach their destination planets or asteroid belts. These space stations can charge transit fees for providing fuel and navigational data to ships, and are a lucrative source of revenue for the regime that controls them.

Tactical and Strategic Implications of the Tunnel Drive

Because ships traveling to a star system from a given neighboring star system will re-emerge from deadspace at predictable points deep inside the gravity well of the destination star, large-scale spaceborne invasions are very difficult, perhaps even impossible. Defensive battlestations, warships, or other fortifications around the gravity well of the central star should be able to handle the one or two ships that can come through at a time quite easily. It is almost impossible to sneak scouts or other warships into a system without the owner knowing about it. Space piracy is very difficult, at least in deadspace, as traffic control authorities will know when all ships enter and exit deadspace at the local star, and the fact that deadspace is on a different time axis from our own means that there is no guarantee that two ships entering deadspace at almost the same time will arrive in deadspace even within a million years of each other, each trip is in a random era of deadspace. This makes fleet actions or almost any other combat within deadspace almost impossible.