I think I may have figured out a new method of opening the gate, which has a lot of potential. As you all know, when a super missile makes contact with any surface, the entire rooms vibrates. At first I thought that vibrations were just visual, but it turns out that the vibrations actually shift the hit boxes of all objects by a couple pixels.
Here is a quick demonstration.
Test #1
In this short movie, a super missile is fired when Samus' y pixel position is at 902, sub pixel position of 35840. The super missile clears the ledge.
Test #2
Now a preemptive super missile is fired in order to cause the room to shake. A second super missile is fired in the exact same position as in the first movie (y pixel position is at 902, sub pixel position of 35840) This time instead of clearing the ledge, the super missile makes contact!
What does this mean?
Like we already know, a super missile can easily pass through the gate itself. And we already knew the super can pass literally 1 pixel underneath the green button. Now if a second super missile can be fired into the closest wall in time, the green button will be shifted and the first super might make direct contact. After some preliminary testing, the speed of the first super missile is hard to keep up with since there is a 17 frame delay before a second one can be fired. I have been within 2 frames of getting the shot off in time. I urge others to try this as well.