Dogur-dann
Dogur-dann started out as a terrestrial world, with an advanced civilization (similar to Earth in the 1990s). Another star passed close to their star, pulling the planet out of its orbit, to wander interstellar space. Luckily, because of their advanced technology, the Dogarri (the local technological species) had advanced warning of the impending disaster, and prepared the best they could. This was mainly accomplished by burrowing underground, and learning to live off their planet's geothermal heat. All life on the surface froze, and even the atmosphere condensed into ice, but the active core of the planet kept the Dogarri alive.
This is the state Dogur-dann was in when it was discovered by the Planetary League, near the colony world of New Promise in GSC 138. Trade and diplomacy was established between the main factions of the Dogarri and the Planetary League under the newly passed Alien Assistance Act. Eventually, the leading factions of the Dogarri joined the Planetary League, while others remained independent.
Most of Dogur-dann was conquered after the end of the Great Reckoning by the Holy Empire of Man.
The Dogarri rebelled and joined the Galactic Republic during the War of Galactic Unification.