In effect the teleportation swings by Xen, and arrives elsewhere on earthĬonversely the teleportation technology developed by Aperture Science is based on portal technology and is in essence instantaneous. Single dimensional teleportation is seen in the second chapter of Half-Life 2, Red Letter Day when the resistance tried to teleport Gordon Freeman to a separate base, and achieved by factoring in 'Dark Energy equations'. ~Half Life Wiki (referencing game events) Teleportation was a major field of study at Black Mesa, and their portals were used primarily in the procurement of Xen crystals, as they were used to transport scientists to and from the Borderworld for research and analysis. As well as this, the dry dock for the Borealis is seen in Portal 2. If you wander around the correct locations in Portal one you see there various slides from presentations that hint at a rivalry between the two companies, both of which were working on similar projects.
The Borealis (containing some Aperture Science portal technology) is sought out by the resistance (remnants of Black Mesa and newly freed citizens) for various means. Black Mesa and Aperture Science, the two focal science companies of the Half-life and Portal series exist in the same in-game biverse and, at one point vied for research funding.
