CT Was the trench run necessary?

The space around the exhaust port was probably well protected so going through the trench was the longest, yet "safest" option.

 

I always thought it was angle related...

 

A kamakzi attack on the exhaust port would not have worked. Remember in the briefing room, the rebel leader states that a missile has to enter deep into the exhaust port to cause the chain reaction. The one rebel pilot before Luke did hit the port, but was slightly off, so the missiles impacted on the surface rather than enter into the port. Slamming a whole fighter into the port would just result in only surface damage and not cause the desired chain reaction which is deeper than the surface. It likely would just block the port from further attacks.

 

I don't remember the briefing saying anything about deep into the exhaust port.

"A precise hit will start a chain reaction which should destroy the station.....Only a precise hit will set up a chain reaction."

A direct hit through the centre of the aperture would, of course, result in the missile going into the shaft itself.

But as long as the missile does not impact on the outer aperture itself, it is implied that the impact with anywhere inside the shaft itself will cause a chain reaction down the length of the shaft

 

My consideration of pilots with 'no tomorrow' doesn't imply they would all individually and intentionally add to the difficulty by complicating the environment around the target. What you are saying is a useful physics to the problem. Any number of pilots will succeed in *not complicating the target area if they overshoot it with their (delivery) craft, while only risking the target area with the miss of much smaller ordinance. So the problem of Why Trench can be reframed as Why Orthogonal, and can be reduced to a matter of the clustering of inertial mass. Straight on, as innocence asks, means the sum of inertial masses of the fighters (+30 * thousands of tons each) has a higher chance of obstructing the target area. The cluster of greatest mass ought not be centered on the target, only the cluster of ordinance. The easiest way to solve the greater problem is for the cluster of delivery mass to overshoot/overfly the target area. I believe this addresses the OP with least appeal to matters of 'no tomorrow'.

 

The shaft is two meters wide and ray shielded. Crashing a fighter wouldn't work. Only a proton torpedo can get through.

 

What did Mr. Charles ever do to those people?!

 

The computer graphic shows the missiles traveling though the pipe for some distance. I doubt a fighter could smash deep enough to hit the machinery the exhaust port is for. You would think most of the critical machinery would be deep under the surface and well protected from impacts. The station is built to withstand capital ship attacks after all, and a barrage from a large ship would penetrate the DS surface better than a suicide bomber.

 

The graphic was showing the chain reaction. IIRC, the shaft that comes out at the exhaust port acts like a fuse. As long as you get the ball through the hoop (all net) you will start the reaction.

 

The ANH radio adaptation, scripted by Brian Daley, had an addition to the briefing. Dodonna notes that the torpedo has to be dropped precisely into the exhaust port, then actually hit the main reactor for the station to ultimately be destroyed. Just hitting the shaft, or getting partway down, won't be enough. Again, I'm not sure if the current canon overwrites this.

 

It hasn't. "Rogue One" says the same thing as in ANH.

GALEN: "My Stardust. Saw, the reactor module, that's the key. That's the place I've laid my trap. It's well hidden and unstable, one blast to any part of it will destroy the entire station. You'll need the plans, the structural plans for the Death Star to find the reactor. I know there's a complete engineering archive in the data vault at the Citadel Tower on Scarif. Any pressurized explosion to the reactor module will set off a chain reaction that will destroy the entire station..."

DODONNA: "The approach will not be easy. You are required to maneuver straight down this trench and skim the surface to this point. The target area is only two meters wide. It's a small thermal exhaust port, right below the main port. The shaft leads directly to the reactor system. A precise hit will start a chain reaction which should destroy the station. Only a precise hit will set up a chain reaction. The shaft is ray-shielded, so you'll have to use proton torpedoes."

The graphic shows that torpedo traveling all the way down and hitting the core.



It isn't an explosion and then the chain reaction reaching down. It's the torpedo going down and making the hit. Just as we see in ROTJ. Destroying the reactor core causes it to overload and explode.

 

In the film, we see Luke's torpedoes fly into the port and appear to travel out of sight in a pipe.

 

If the missiles needed to travel the length of the conduit that comes out at that port, then that makes Luke's shot even more incredible.

Hitting a two metre wide target is one thing. Ensuring that the path of the missile does impact on the walls of the conduit as it makes its way down to the reactor means hitting a target that is two metres wide, invisible and from a distance of half the diameter of Death Star.

That means hitting a two metre wide target that you can't see from around 75,000 metres away.

 

And another perspective:

 

Also how he managed to make the torpedoes turn 90 degrees.



In the gif above, it does appear the torpedoes do indeed travel down the conduit. The torpedoes must have some self guiding ability to make the 90 degree bend and travel down the shaft. You can also see the crater from the near miss of the prior trench run to the left.

 

That's why only a Jedi could make that shot. Ever since the second draft when the Force became an energy field that could be manipulated and allow someone to see things before they happen, it was always dependent on Luke making that shot and in each version he is only able to do so because he's a Jedi. That's why Lucas set up the two failed bombing runs with Gold Leader and Red Leader. The first fails to get the shot off and the second does, but it misses. Luke had been able to make similar shots because of the Force, but he wasn't aware that was why he could hit a womprat as precisely as he did. Why a targeting computer could never make that shot as Wedge noted. If Obi-wan were alive and flying, he'd make that shot. Same with Kanan and Ezra if they were there.

 

I figure that the missiles have the equivalent of a cruise missile's terrain guidance system - if they get into the right position at the entrance of the shaft, Luke doesn't need to guide them any more - they'll do the rest.

 

That's a stark statement. So how do you process what Rogue One revisions? Galen is absolved of culpability for not making his installed weakness a little more accessible to the non-Jedi handicapped, or, The Force was whispering into Galen's ear that 'it's ok, I have a Jedi in the pipe so you can make it too hard for mere mortal pilots, because he's good for a one-in-a-million feat'.

I prefer what you say here, which dictates, mathematically, I think, that I completely dis-prefer Rogue One's complexion of events.

 

In my headcanon, Galen designed the reactor to blow up, but was vague about how to trigger the explosion. He may have envisioned an infiltration team sneaking on board, planting explosive charges in the reactor room, and sneaking out. Obviously there wasn't enough time to do all that at Yavin, so the rebels came up with a desperate one in a million Plan B.

 

As I understand based on the novelization and movie, any large enough detonation could have destroyed the reactor. However, Galen didn't believe that it would be likely the rebels could get a team through the Death Star's security, and so the secondary exhaust port was added to give an external assault at least a chance of succeeding. (It also had the side affect of mildly irradiating enlisted troop quarters but Krennic didn't care.) If there had been time, a sufficiently determined and stealthy team could have snuck aboard and done the same thing.

 

I haven't read the novel, so I'll take your word for it. Judging by Ep IV, an infiltration team probably could have done it eventually, since a scratch team of randoms managed to infiltrate the prison block, release and escape with the most important prisoner on board. Internal security is apparently sadly lacking.

 

I thought it was rather clever the way, in the memos, Galen makes his objection to the thermal exhaust port known - yet Krennic and his underlings are the ones to insist on it - because Galen has made the other options look time-consuming and impractical.

Krennic's last moment realisation of what Galen's done, before he dies, also works well I think.

 

The problem with this is that the rebels, specifically Luke, don't do this. They fire missiles at the port from an oblique angle, and the ymake their way through the aperture thanks to some guidance system.

There's no line of sight to the reactor which would enable a pilot to get a target lock on it. Energy or hest seaking missiles removes the need for accurate aiming.

So I'm going with the exhaust port being like a fuse. As long as you get directly through the aperture, a chain reaction is inevitable which will destroy the reactor and the base.