Deflector shield Deflector shields or screens , generally referred to simply as shields and also as shield grid or planetary shield , were a type of force field that surrounds a starship , space station , or planet to protect against enemy attacks or natural hazards . Operation . Deflector shields operated by creating a layer , or layers , of energetic distortion containing a high concentration of graviton s around the object to be protected . On starships , the shield contained six sections , forward , starboard , port , aft , dorsal , and ventral . ( ) Shield energies could be emitted from a localized antenna or " dish " , such as a ship ' s navigational deflector , or from a network of " grid " emitters laid out on the object ' s surface , such as a starship ' s hull . Since at least the 23rd century , deflector shields were essential equipment on starships . Neither matter nor highly concentrated energy could normally penetrate a shield . When shields were " up , " or energized at a high level , most matter or energy that came into contact with the shields was harmlessly deflected away . This was important in starship combat , as shields were essential for hull protection . When the shields were up , only minor hull damage would be expected during combat . In the 23rd and 24th century , without deflector shields weapons were capable of causing catastrophic damage to starship hulls almost immediately . ( ; ; ) Continuous or extremely powerful energy discharges could progressively dissipate the integrity of a shield to the point of failure . Shield capacities varied according to many variables , from the power available to environmental concerns , making definitive and universal calculations of how much damage they could take difficult to estimate . Therefore , during combat tactical officers would continually report on shield strength , usually as a percentage of total effectiveness , with 100 % meaning that the shields were at full capacity , and lower percentage scores indicating weaker shield conditions . Specific sections of the shield grid could take more damage than other sections , and be reinforced with additional power reserves , so tactical officers would report on the health of the shields by section if need be . Shields were said to be " holding " if damage was not sufficient enough to allow a compromise ; if the shields were " buckling " or " failing , " then a total loss of shield protection was imminent . ( ) Shields operated within a range of frequencies to allow certain specific types of energy and matter to pass through , or to increase the effectiveness of blocking them . The frequencies of shields were not usually discernible without examining the controls on board the ship deploying them , meaning that it was very difficult to tune weapons to the exact frequency of an opponent ' s shields to bypass them . ( ; ) In combat situations , starships would match their own shield and weapon frequencies so their shielding did not interfere with their own weapons . Some weapons technologies , including those commonly used by the Borg , had rapidly adjustable frequencies , meaning that they could quickly penetrate a shield that was using a static frequency . An effective counter was to repeatedly and randomly alter the shield harmonics to minimize the effectiveness of the weapon ' s retuned frequencies , though this tactic amounted to little more than a stall against the Borg . ( ; ) It took time to activate a deflector shield . A refit starship needed exactly 13 . 5 seconds to lower and raise its shields when taking a shuttlecraft on board via its tractor beam , though that included the time required to tractor in the shuttle during an automated docking procedure ; flying the shuttle in manually reduced this time significantly . ( ) Shields on a starship could be fully recharged after charging the shield emitters for 45 seconds . This task required the shields to be dropped . ( ) Normally , transporter s were not capable of penetrating shields . ( ) Twenty - third century Federation starships , such as the " Constitution " - class , could not transport through their own shields , but later starships such as the vessels could transport personnel and objects freely to and from without having to lower their shields . ( ) There were at least two different shield configurations commonly used by Federation starships . One type projected an ellipsoid shield bubble around the ship and a relatively large region directly adjacent to the ship . The other shield configuration used a contour - conforming shield layer projected a few meters outside the main hull . Some starships had a shield system advanced enough to allow protection of only specific areas of the ship , leaving other areas unprotected . This was useful in times when power reserves are low . Lowering portions of the shields would allow the use of transporters without completely sacrificing the protection that shields provide . This was also useful if a captain wanted to leave a section of the ship unshielded , like a cargo bay . ( ) Shields could be " extended " to encompass another vessel which couldn ' t use its own shields . ( ) This could also be used on ships with weaker shields , by matching the ships ' shield emitter frequencies . ( ; ; ) While the extended shielding could provide some protection in the event of a shield failure on one ship , this technique put a strain on that ship ' s systems , and the overall strength of the extended shields was generally not as strong as two independent shield systems . Strength . Shield strengths seemed to vary , making an exact calculation of how much damage they could take impossible . However , there were some examples : Use . In 2369 Major Kira Nerys and Lieutenant Jadzia Dax re - calibrated the inner deflector shield subsystems of Deep Space 9 . ( ) Hand - held . In 2369 , Starfleet made first contact with a species from the Gamma Quadrant , the Hunter s . The first contact ended in a shootout on the Deep Space 9 Promenade in which the Hunters used a hand - held deflector shield , integrated into their uniforms on their left arms . These shields collected the phaser fire and bundled the fire , letting the Hunters take several phaser shots without being hit . ( )