Location: Milky WayStyx ThetaAcheron System Second planet

Prerequisite: Noveria: Geth Interest


Altahe is an exceptional form of planet called a Roche World. Put simply, it is one half of a pair of small and unusually dense terrestrial worlds (Altahe and Ontahe) that orbit each other so closely, they effectively share a single atmosphere. That does not mean one could fly from one to the other, but both have identical atmospheres and dust from one often can be found on the other.

Both worlds share an atmosphere of nitrogen and ethane. The surface is warm, and mainly composed of silica dust and dark basaltic rocks, with extensive deposits of heavy metals and radioactives. Tidal effects from Ontahe create constant heavy wind.


Points of InterestEdit

Location Appearance Description
1 Initial Listening Post (UNC: Listening Post Theta)
2 Discovery Anomaly (UNC: Asari Writings). The "song" commonly associated with the rachni can be heard near the wreckage.

“This downed satellite had one of Matriarch Dilinaga's writings stored in its payload. Whether it was placed before or after it crashed is uncertain.”

3 Discovery Crashed Pod (salvage)
4 Unmarked Rachni colony

Mineral DepositsEdit

Altahe SLI
Main article: UNC: Valuable Minerals
Location Element Class
1 Samarium Rare
2 Gold Heavy



Ontahe is strictly speaking the second partner in a dual system, Charon to Altahe's Pluto. Both likely orbit with synchronous rotation to one another; Ontahe is always in the same place in Altahe's sky and always shows the same face.

At the Mako landing site, Ontahe is visible near the horizon. This hints that the Mako has landed far from the equator (where Ontahe would be directly overhead), around one of the arctic circles.

The rachni appear on this planet regardless of Commander Shepard's decision concerning the Rachni Queen on Noveria as they were sent to Depot Sigma-23 before the lockdown at Peak 15.


  • The name given for the planet type, a Roche world, is likely referring to the Roche Limit. This limit describes the distance at which a celestial body orbiting another will begin to disintegrate as tidal forces overcome gravitational binding.
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