All shields seen in ANH deflected
turbolaser/laser/blaster fire when fired upon, but were not seen to
deflect missiles or actually stop ships from flying through.
The Millenium Falcon has
deflector
shields, which may be angled in anticipation of attacks, and may
fail against repeated battery. It is seen protecting the Falcon against
turbolaser fire from Imperial Star Destroyers. Presumably most ships
carry deflector shields; X-Wing and Y-Wing fighters' deflectors have
distinct front and rear systems. TIE fighters are usually destroyed
when
directly hit, leading to the suggestion that they have weak or
nonexistant shields.
Shielding is not visible in ANH, although the occasional close blue
flak burst may, in fact, represent a shield impact, rather than the
flak
bursts mentioned in the novel.
The Death Star is
"heavily
shielded." Fighters flew up to the Death Star with little to no
difficulty, aside from some buffeting within its
"magnetic field." When
tractoring the Falcon inside, they opened a
"magnetic field";
presumably, and from the context of previous uses of
"magnetic field" in print
, this is a
repulsorfield of some sort.
The ventilation shaft attacked on the Death Star was
ray-shielded, a type of shielding
that stops turbolasers but not proton torpedos. We may assume, judging
from the Death Star's presumed invulnerability
, that
there were larger ray shields or deflector shields around the Death
Star
preventing larger ships from firing upon it. There is no skintight
shield around the main portions of the Death Star, as evinced by the
explosive results of Rebel fighter fire made upon the surface; however,
it may simply be the case that the Death Star's armor is expected to
hold up long enough for its weapons turrets to destroy any attacking
ship.
At
least one edition of the script, interestingly enough, refers to Luke's
landspeeder as floating on a magnetic field. It is reasonable to
conclude from his uses of the term that by magnetic field,
Lucas is referring to some field
that is repulsive.
The Death
Star clearly was not physically invulnerable to attack. Attacked
directly by X-Wings, the Death Star took minor but very real physical
damage.
This tower exploded shortly after
being fired upon by incoming X-Wings. Other attacks by the X-Wings on
the surface of the Death Star produced sparks and cosmetic damage, but
the occasional explosive success of strafing runs in penetrating the
armor of the Death Star and blowing up portions of it suggests that a
greater number of fighters, or more powerful vessels striking from
close
proximity, could strip the Death Star of its defensive guns in a great
hurry and eventually disable the station itself.
That attack with an external fleet is not suggested as part of a
feasible means of taking out the Death Star suggests either that ray
shield or deflector shield surrounds the Death Star, preventing long
range turbolaser bombardment, or that the Rebels cannot supply any
fleet
of note.