What damage did Red Leader's torpedoes cause to the Death Star?

Question

I've always wondered how, after Red Leader's two proton torpedoes impact on the surface of the Death Star, were Luke's torpedoes able to even come close to making correct navigation through the thermal exhaust port? Surely an explosion would cause terrible damage to the surrounding area and yet we see no obvious damage to the area around the target.

RED LEADER: Negative! It didn't go in. It just impacted on the surface.

Is there any evidence as to where Red Leader's torpedoes impacted? Did they fly out of the trench only to "impact on the surface"? Or did they impact the surface of the trench? In short, what damage did Red Leader's torpedoes cause to the Death Star?

Answer 1

In short, the Death Star was so heavily armored that little to no damage was done -- it was necessary to get the torpedoes down the thermal exhaust port to have any real effect.

There is a GIF in this other SFF post that shows direct evidence from the movie. Red Leader's torpedoes did little damage to the port; just a little scorching.

Think about how Bard's arrow wouldn't have done any damage to the dragon Smaug in The Hobbit if it hadn't hit that one place missing a scale...or how Apollo directed Paris's arrow to Achilles' one vulnerable spot...

Answer 2

In real life, ship-fired torpedoes have a feature known as an arming run to prevent a torpedo from detonating too close to the firing craft (http://www.navweaps.com/Weapons/WTUS_WWII.php). The warhead of the torpedo is armed only after the torpedo has moved a preset distance away from the launching craft.

If I were a Wing Commander of a flight of X-wing fighters, assigning my pilots make precision attack runs against a small target, flying in single file formation within the confined close quarters of the equatorial trench of a space station, I would make sure that the explosion of a proton torpedo that missed would not adversely effect the spaceframe, targeting sensors, shields, or pilot eyesight of the next fighter on the attack run - allowing for maximum survivability of my fighter group and better odds of a successful mission. A successful proton torpedo would have to travel a long distance from the opening of the thermal exhaust port to the main reactor of the Death Star - it makes tactical sense to use the arming run of the torpedo to prevent the torpedo from detonating prematurely.

So, it is my theory that the proton torpedoes used in the assault on the Death Star were configured with an arming run, and at the time of impact on the surface of the Death Star, did not have armed warheads and the minimal damage sustained by the surface of the Death Star was only the result of the amount of kinetic energy the torpedoes transferred to the surface armor.