Kessel was a planet that hosted major mining facilities. The Galactic Empire operated a mining operation, employing numerous slaves, including Wookiees, to harvest spice. Slaves who were sent to Kessel worked in harsh, brutal conditions.
The planet Kessel was first mentioned in the 1977 film A New Hope. Its first canonical appearance was in Star Wars Rebels: Spark of Rebellion, the premiere of the animated television series Star Wars Rebels. The series used designs and concepts created for Kessel by Star Wars creator George Lucas, who developed its appearance, culture, and economy.
The planet was also mentioned in 2015 film Star Wars: The Force Awakens.