Source GM Core pg. 96

Outer space holds countless stars, planets, derelicts, and Rift‑scarred anomalies between them. Most characters eventually cross open void—whether shuttling between Inner Sphere ecumenopolises, docking at an orbital station, or risking a long Rift‑lane to a distant Frontier system. Almost all such travel relies on starships or sealed platforms that shield travelers from vacuum, radiation, and time‑skewing Rift turbulence.

Cosmic Radiation: Usually, creatures not protected by an atmosphere are constantly exposed to mild to severe radiation.

Metronomes: Metronomes act as landmarks for Rift travel, relay long-range communications through outer space, and mark the passage of time in 16.6 minute pulses.

Solar Flares: Solar flares disrupt technology up to millions of miles away from the star.

Vacuum: Space is a vacuum, meaning it contains no breathable air and has zero gravity.

Decompression:Decompression occurs when a creature suddenly transitions from a pressurized environment to a vacuum, such as by getting shoved out of an airlock or being inside a starship that sustains heavy damage.