Tuchanka

Mass Effect 2 Codex Entry
The krogan homeworld boasts extreme temperatures, virulent diseases, and vicious, predatory fauna. Around 1900 BCE, the krogan discovered atomic power and promptly instigated many intraplanetary wars, sending Tuchanka into a nuclear winter. With most of their industrial base destroyed, the krogan entered a new dark age and warring tribal bands dominated. Populations remained low for the next 2000 years.

First contact with the salarians made resurgence possible. Krogan brought to less hostile planets bred exponentially and returned to reconquer their home. They built vast underground shelters to shield themselves from surface radiation, which proved prescient during the Krogan Rebellions when many of them isolated themselves in a vain attempt to avoid the genophage. Convinced they could outbreed the genophage, they transmitted it to more than 90 percent of the sealed bunkers. Today, Tuchanka's population is sharply limited and while individual krogan are long-lived, the genophage ensures few replacements.

Mass Effect 3 Codex Entry
Tuchanka, the krogan homeworld boasts extreme temperatures, virulent diseases, and predatory fauna. Around 1900 BCE, the krogan discovered atomic weapons and promptly sent their planet into a nuclear winter. The majority of the population retreated into underground bunkers, and krogan culture slipped into a dark age dominated by tribal clans.

In 80 CE, decades into the Rachni Wars, the Salarian Union made first contact with the primitive krogan and initiated a "cultural uplift" to shape them into a modern army capable of confronting the rachni. During this uplift, the salarians constructed the Shroud facility on Tuchanka to shield the planet from harmful forms of solar radiation. Later, during the Krogan Rebellions, reproductive rates were curtailed by the genophage, ensuring the krogan remained a species in decline--and Tuchanka a desolate wasteland.

Mass Effect 2 & Mass Effect 3 Solar System Entry

 * Capital: currently Urdnot (since 2183)
 * CDEM Garrison: 2,400 (in orbital battlestations)
 * Surface Temperature: 72 Celsius (36 in shrouded areas)

Scarred by bombardment craters, radioactive rubble, choking ash, salt flats, and alkaline seas, Tuchanka can barely support life. Thousands of years ago, life grew in fierce abundance under the F-class star Aralakh (a Raik clan word meaning "Eye of Wrath"). Tree-analogues grew in thick jungles, their roots growing out of shallow, silty seas. Life fed upon life in an evolutionary crucible. This world died in nuclear firestorms after the krogan split the atom. A "little ice age" of nuclear winter killed off much of the remaining plant life.

In recent centuries, many krogan have returned to their homeworld. The reduced albedo has caused global temperatures to rise. In order to maintain livable temperatures, a vast shroud was assembled at the L1 Lagrange point. It is maintained by the Council Demilitarization Enforcement Mission (CDEM), which is based on orbiting battlestations.

CDEM ADVISORY: Visitors to Tuchanka land at their own risk. The CDEM will not attempt to extract citizens threatened by clan warfare.

TRAVEL ADVISORY: The ecology of Tuchanka is deadly. Nearly every native species engages in some predatory behavior; even the remaining vegetation is carnivorous. Travel beyond guarded areas is strongly discouraged.