(edited: not helpful: )
key == ' '
instead of keyCode?

Why do you use both keyPressed and keyReleased?

Advice: take a bit of time and make a simple runnable sketch instead of providing a fragment of code.
Thus, we can quickly test your problem.
Being intrigued, I did this step myself:

1. void setup()
2. {
3.   frameRate(5);
4. }
5. void draw()
6. {
7.   println(thrust + " " + turn + " " + fOB + " " + lOR);
8. }
9. boolean thrust, turn, fOB, lOR;
10. void keyPressed() {
11.   if (key == CODED) {
12.     if (keyCode == UP) {
13.       thrust = true;
14.       fOB = true;
15.     } else if (keyCode == LEFT) {
16.       turn = true;
17.       lOR = true;
18.     } else if (keyCode == RIGHT) {
19.       turn = true;
20.       lOR = false;
21.     }
22.   }
23. }
24. void keyReleased() {
25.   if (key == CODED) {
26.     if (keyCode == UP) {
27.       thrust = false ;
28.     } else if (keyCode == LEFT || keyCode == RIGHT) {
29.       turn = false;
30.     }
31.   }
32.   if (key == ' ') { // keyCode also works here
    
33.     println("player.fire()");
34.   }
35. }

Indeed, UP+LEFT+space doesn't work while UP+RIGHT+space works.
Since they are treated in a quite symmetrical way, it is puzzling. Is it some kind of keyboard limitation?
If I change the test to (key == 'f'), it works! Idem for (keyCode == CONTROL). Looks like you must change your keyboard controls...