Shield deflects

Admiral Ackbar stepped forward. His specialty was Imperial defense procedures. He raised his fin and pointed at the holographic model of the force field emanating from Endor. “Although uncompleted, the Death Star is not entirely without a defense mechanism,” he instructed in soothing Calamarian tones. “It is protected by an energy shield which is generated by the nearby Moon of Endor, here. No ship can fly through it, no weapon can penetrate it.” He stopped for a long moment. He wanted the information to sink in. When he thought it had, he spoke more slowly. “The shield must be deactivated if any attack is to be attempted. Once the shield is down, the cruisers will create a perimeter while the fighters fly into the superstructure, here  … and attempt to hit the main reactor …” He pointed to the unfinished portion of the Death Star “…  somewhere in here.”

***

Star Wars Trilogy, Return of the Jedi Chapter 4