A to Z: R is for Rift

A Rift is an area of low stellar density. Rifts act as impediments to interstellar travel in that starships with short range Jump Drives find it difficult to cross them. The chief reason for this is a lack of fuel sources in the Rift.

As Jump Drives require hydrogen as fuel to operate, Jump Drive-equipped starships tend to jump from star system to star system, refueling at a local gas giant (fuel skimming) or planet with free standing water, if they possess on-board fuel refineries, or from local starports. It is possible to extend a ship’s range by carrying extra fuel-tankage, either externally in a drop tank, or internally as a refrigerated and pressurised bladder rigged in the cargo bay.

External tanks increase the mass of the ship, and reduce the efficiency of its Jump Drive. The usually method of operation when using drop tanks is for the ship to use its external fuel load for its initial jump, discarding the, now empty, external tanks as it transits to Jump Space. Upon returning to Normal Space, the ship will use its internal fuel load to make a subsequent Jump. While there are pros and cons with using this Jump method, it does extend the range of the ship while increasing the running costs in expendable tankage. The Gazelle Class Close Escort is a small warship that uses this method of operation. It is relatively unusual to come across a civilian vessel using Drop Tanks, unless it is working a regular route with some form of government subsidy.

The use of a fuel bladder rigged in the cargo bay is the other method for extending the range of a starship. The most obvious disadvantage in this method is that the more fuel carried, the less room there is for cargo, and the less likelihood that a particular voyage will cover costs. This method is commonly used by short range starships wishing to move between Mains or Clusters to follow the trade. The ship will leave its current Main and jump to a point in Deep Space. The ship’s fuel tanks are then refilled by pumping the hydrogen slurry from the bladder in the cargo bay into the tanks. Once the refueling is complete, the ship Jumps to its destination.

Rifts, by their nature, funnel trade and travel and, if sufficiently wide, make for relatively secure borders. Ships that can cross Rifts will command a premium as to go around the Rift can add months to travel time. Systems astride Rift crossing points tend to either be tense conflict zones or heavily defended as neighbouring polities attempt to control the choke point.

In the Rimward portion of the RimWorlds, there are two major Rifts: the Perrsherrik Rift and the Uedhkinthuez nakhae. While neither is anything close to the vastness in size of the Great Rift that isolates the Spinward March, both Rifts have had effects on the way trade and populations have moved in the RimWorlds.

The Perrsherrik Rift is a Jump 3 Rift running 13 parsecs to Trailing from the Tallu Cluster in Lymethius Subsector to Lotarf/Nolgor. This Rift effectively divides Gamelea and Nolgor Subsectors in two, and delayed Imperial expansion Rimward for decades. Jump 3 crossings can be made at Leminkainen – Anthorann, Leminkainen - Kalath, Solaris – Gilanda, Solaris – Xcothal and Thrisk – Lotarf. Only the Leminkainen – Anthorann, Leminkainen – Kalath and Thrisk – Lotarf routes have proved commercially viable, and the Thrisk – Lotarf route has fallen under the control of the Theocrats of Lotarf.

In the Cabria Subsector, the Uedhkinthuez nakhae ("The Black Beast" in Arrghoun – the language of the Vargr of the Hunt of Rronurl) is a Rift running 9 parsecs to Rimward from Gyffd and Gaidon in Cabria Subsector into Kfukskho Subsector. The main crossing point is at Yuar, a Droyne world. The Yuar Droyne run a regular Carryall service from Yuar to Brol, Nutharal and either Juchis or Gyven’s World – a Carryall is a massive spar with an oversized Jump Drive and anchor points for up to a dozen ships in the 200 – 400 ton range. The smaller ships are effectively carried as cargo by the Carryall. The Droyne service is prone to cancellation with little notice for particularly inscrutable Droyne reasons.

During the Outrim Wars, the Uedhkinthuez nakhae saved the Imperial-held Miazan Subsector from the worst of the Outrim Alliance’s initial assaults as the Alliance’s fleets had to either stage through the Hunt of Rronurl to Rimward, or move Coreward through Gyffd before they could engage Imperial targets. Even when Yuar sided with the Alliance, it took time for the Carryalls to bring sufficient of the slower Alliance ships across the Uedhkinthuez nakhae to open a front.

While rumours abound of secret Deep Space refuelling stations being built or established on wandering planetoids, deep in the Rifts, there has been no evidence that such facilities exist.