Impulse energy buffer

An impulse energy buffer was a technology used to minimize the effects of starship impulse engines.

Following the discovery of the Bajoran wormhole and the existence of the Prophets, any starship crew that required access to the wormhole had to drydock their vessel at Deep Space 9 to have impulse energy buffers mounted around their impulse engines. Some races, like the Cardassians disliked having to do so. 
 * The concept originated in the DS9 series bible and early drafts of "Emissary", but did not make it to screen.