Starfleet Records. Shield technology. Deflector shield: Operation. Some starships have a shield system advanced enough to allow protection of only specific areas of the ship, leaving other areas unprotected. This is useful in times when power reserves are low. Lowering portions of the shields allows the use of transporters without completely sacrificing the protection that shields provide. This is also useful if a captain wants to leave a section of the ship unshielded, like a cargo bay. Source: