Soyuz

Soyuz is the main homeworld for the Soviet Union as well as its capital planet. It is known (or notorious) for its nippy climate, long days and nights and relatively high gravity.

History
The planet that would be called Soyuz has orbited the Solidarity binary system for 4.8 billion years, and Soviet paleontologists have found that life has existed there as early as 4.5 billion - only 300 million after the planet's formation. Due to the presence of the red dwarf star Solidarity B (commonly called Engels), which emits dangerous solar flares, life on Soyuz has evolved a strong resistance to ultraviolet radiation. The presence of Solidarity A and the distance away from Engels mitigating the flares also helps.

It was discovered by the Soviet Union's space program in April 2nd, 1970 and then colonized in February 10th, 1971. It was declared the new capital two days later.

Wildlife
The native creatures and plants on Soyuz have been hardened and toughened by its high gravity, elevated UV radiation levels and cold but dynamic climate.