A quasar cannon is a planetary defense mechanism in the fictional TradeWars 2002 universe. It can be calibrated to fire upon any ship that enters the same sector as the planet or attempts to land. Large amounts of fuel ore are consumed by quasar cannon shots. For this reason, some attackers use expendable ships such as the Merchant Freighter to drain the cannon's fuel supply. This type of attack is referred to as "mothing."