The Borealis was a shipping vessel owned and operated by research corporation Aperture Science. It is believed to hold some type of powerful technology, perhaps a more advanced implementation of its portal technology. In recent times it has become an object of interest to both the Combine and human Resistance.
At some point during dry-docking, the Borealis mysteriously vanished, tearing a section of the dry dock away in the process. The sheer unlikelihood of such an event has helped cement the status of Borealis
as a legend or myth amongst the scientific community at large. The Borealis
had been transported to a barren region of the Arctic, where it would remain untouched until after the events of the Seven Hour War.
In the days following the destruction of the Combine's Citadel in City 17, Dr. Judith Mossman
travelled into the far north and discovered the resting site of the Borealis
. She attempted to transmit information on the ship's location to the Resistance, but it was intercepted by the Combine. This information was obtained by Gordon Freeman
and Alyx Vance
a short time afterwards, who then made sure it ended up in rebel hands. The Borealis,
and whatever it contains, will likely become the next point of contention between the Combine and the Resistance in their struggle for Earth.
A hidden side area in Portal 2
, which takes place at the primary Aperture Science Testing Facility, appears to be the docking area for the Borealis
, complete with a chunk torn out of the landscape from the sudden teleportation.