Orignally produced by AvaNet, the computer-society that once inhabited the south islands of Planet Yamatai, the Transuniversal Teleportation Drive system was a mysterious device that created quantum links from one universe to the next, allowing starships to instantly blink out of existence in the Yamatai universe, and reappear in another universe entirely. The Star Army of Yamatai sent out several expeditionary forces to various alternate universes during its early years, but many were met with extreme danger or simply overwhelmed by the natives.
As war erupted in Yamatai space (including fighting extra-universal aliens), the age of TTD usage came to a close; the Yamatai Star Empire decided to focus on their home universe first and started a campaign to rid the universe of transuniversal devices, removing them from Star Army ships and destroying most. Shortly thereafter, AvaNet was banished and nearly eradicated as well.
These days, due to bad experiences with other universes in the past, transuniversal drives are highly illegal to possess (they're on the top of the restricted technologies list and the only technology Nepleslia's government was not allowed by Yamatai) and using one is considered a crime against the universe because it potentially puts all of Yamatai space in danger. The Star Army of Yamatai has been successful in keeping the devices in the hands of the Star Army Research Administration, which maintains the hundred or so spare devices remaining, “just in case.”
Rarely, some older Star Fortresses, flagships, Ayame cruisers, and other “hub” type vessels will still carry a TTD. These are exceptions and are extremely well protected. Any ship carrying a TTD must be destroyed if capture is imminent.
The TTD primarily existed to permit crossovers with other role-playing communities, back when the Star Army Role-Play was very small. Nowadays, it isn't really needed and exists primarily as a relic. The TTD is not to be used as an alternate FTL system in the Star Army RP. Any TTD usage should have a hyperlink to the destination universe's RP forums, if available. Usage of a TTD requires posted permission of a StarArmy.com administrator.