Mass Effect Wiki
Mass Effect Wiki

Location: Milky WayKepler VergeNewton System First planet

Prerequisite: Priority: Thessia (Mass Effect 3)


Mass Effect[]

Though Ontarom's surface is uncomfortably hot, its nitrogen-oxygen atmosphere and abundant, shallow seas make it an ideal candidate for habitation by most known species.

Unfortunately, the orbit of the moon of Thonal has been slowly decaying since the system coalesced. Its proximity is beginning to have tidal effects, and its dynamo-like revolution through Ontarom's magnetic field is generating increasing powerful electrical storms.

While some have suggested emplacement of mass effect drives in an attempt to lighten the moon and correct its orbit, the scale of such a project – tens of thousands of drives, costing enough to bankrupt the governments of all the Citadel races – make it a pipe dream. A multi-racial effort is underway to catalogue and preserve the unique genetic diversity of Ontarom's vibrant young biosphere. ExoGeni Corp. and Heyuan Genomics represent the Alliance's share of the effort.

Mass Effect 3[]

This habitable world had been living in the shadow of disaster long before the Reaper war--its moon's orbit is decaying, causing tidal disruptions and electrical storms before its eventual collision.

When humans settled on Ontarom, the asari derided it as foolish, but today the humans look prescient. The communications hub they set up on the planet has hundreds of quantum communicators, whose information is spread through broadcast on the planet and beamed out via comm buoy. While Ontarom has yet to be attacked by Reaper forces, it is likely just a matter of time.

Codex Entry[]

Sixteen years ago, the Systems Alliance established the first dish field on Ontarom, defying the tidal disruptions and electrical storms that periodically sweep across the planet. The facility has since grown into a crucial communications hub for the Alliance.

Trade between the Alliance base and nearby human settlements sustains planetary unity. The Alliance also trains and hires colonists to maintain the quantum communicators, further strengthening the bond between locals and the military forces that use the comm stations.

Although most of the communication relays serve the military, a coalition of Ontarom's businesses has begun construction on a civilian broadcast hub. The local Alliance commander has offered the help of the military's technical experts, making Ontarom a symbol of civilian and military cooperation.



Points of Interest[]

Terrain Map
Location Appearance Description
1 Initial Underground science facility (UNC: Dead Scientists)
2 Initial Crashed probe (salvage)
3 Initial Turian corpse and wreckage and Space Beetles (UNC: Turian Insignias)

“It's unclear what happened to this turian. He had an ancient paper book with the Bostra Outpost insignia printed on the cover.”

4 Unmarked Space Cow herd (including a Shifty Looking Cow)

Mineral Deposits[]

A falling moon
Main article: UNC: Valuable Minerals
Location Element Class
1 Gold Heavy
2 Palladium Heavy



The operational area in 2183 is mostly a massive, even-surfaced plateau with deep gorges in between. This lends to a calm straight drive at the top and moderate mountainside sloping that the Mako won't have much difficulty climbing. However, three of its five points of interest are in the interstitial elevations, which may require a few drives up and down cliffs.