The Heavens (To the Heavens Supplement)
From D&D Wiki
The Heavens is a huge, self-supporting starship, capable of holding up to 1/2 billion human beings, and initially transporting 200 million. The U.N.C.S. built it to counter the over-population problem, and it was launched on Sep. 17th, 2460. Less than 2 space-years later, The Heavens encountered the hostile alien race known as the "keshalyen", and subsequently lead them to Earth...