The current state of T'au FTL

Hello all,

The 'T'au FTL retcon' is a reasonably well known controversy. In 6th edition, the prior background from Battlefleet Gothic Armada (as in the rulebook, not the PC game) and Imperial Armour Vol. 3 seemed to have been superceeded, with the introduction of the ZFR Horizon accelerator engine, and later the AL-38 Slipstream Module.

However, later sources like War of Secrets made it clear thar these additions to the lore were just that, and didn't actually retcon away the prior technologies.

If it was the empyrean spoken of by our gue’vesa contacts, it was deeper than we ever suspected. We had only skimmed the surface of that great ocean before, but now, with the Slipstream, we were in its depths

So, where does this leave us?

In rough chronological order, we have the following:

First Sphere:

  • The T’au are able to colonise their system using Gravidic Drives, fast but sublight propulsion

  • Discovery of an alien vessel allows for the T’au to create a method of ‘bouncing’ off the warp using their Gravidic Drives to jump ahead immense (but not unlimited) distances. This requires a lot of energy, and lengthy wind-up times. However, the T’au are able to use this technology to leave their home system for the first time.

Second Sphere:

  • The ZFR Horizon accelerator engine vastly increases the sublight speeds available to T’au ships to near light speed, allowing for more efficient usage of travel time between jumps.

  • Contact with the Imperium and Tyranids forces the T’au to modernise their fleet, and research into true Warp Travel begins.

Third Sphere:

  • Impulse Reactors are developed, increasing the available power (and thus the frequency of jumps)

  • The AL-38 Slipstream Module is produced. When combined with the existing technologies, it allows T’au ships to actually enter the Warp for the first time.

Fourth Sphere:

  • When many AL-38 Modules are activated at once, they drag the 4th Sphere fleet fully into the warp.

  • The AL-38 project is scrapped, and development on future FTL technologies cease as the Empire enters a more conservative stage of its development.

Fifth Sphere:

  • Once contact is reestablished with the 4th Sphere Fleet, work on a new Slipstream drive begins.

  • Extensive experimentation is carried out on the Startide Nexus, in order for the T'au to understand (and possibly even replicate...) it

Sources: Battlefleet Gothic Armada, T’au Codices (6th ed-present), Damocles Warzone Books, War of Secrets, Shadowsun : The Patient hunter