Deflector field

A deflector field is the energy field created by the deflector array of a starship. A deflector field is typically initialized automatically, though in extreme circumstances, it has to be activated manually.

When the USS Defiant (2370)'s computer systems were rendered inoperable by a cascade virus in 2373, the deflector field had to be manually initialized by the bridge crew when the ship undocked from Deep Space 9. 

The deflector field had to be manually activated on a severely damaged USS Voyager after a Krenim scientist altered the past in 2374.