A waste heat vent located on the first Death Star.
A thermal exhaust port functioned as a heat dissipation mechanism. Massive energy reactors aboard starships, space stations, and certain land-based installations produced substantial excess heat. To prevent damage to equipment or harm to personnel from overheating, these ports channeled the excess heat away from reactors and other systems, venting it into the vacuum of space or the surrounding atmosphere.
These thermal exhaust ports were well-known for being susceptible to damage or acts of sabotage. Detonation within an exhaust port had the potential to initiate a cascading explosive reaction, leading to a critical failure and subsequent explosion of the main reactor. Therefore, these ports often featured protective measures, such as physical barriers or ray shielding to defend against energy weapons.
The destruction of the original Death Star by Luke Skywalker is a prime example of the critical vulnerabilities that the placement of these ports could create when overlooked. The Death Star's thermal exhaust port represented a key design flaw that the Rebel Alliance successfully exploited during the Battle of Yavin. As a result, thermal exhaust ports were eliminated from the design of the Death Star II, although the Death Star III maintained this weakness.
As another instance, Kyle Katarn caused the destruction of the Imperial Robotics Construction Facility Ice Station Beta by strategically placing sequencer charges within the facility's network of thermal exhaust ports.