# Would turning a Death Star protect the trench?

When Earth rotates, everything on the surface rotates with it (because friction and because air rotates with it, etc.)

However, in space, that is not the case. Fighters managed to get on the same velocity and direction as the death star and moved relative to its position. Therefore, if Death star suddenly changed its direction, shifted or rotated unexpectedly as much as 1 degree ("upward" or "downward"...so the equator moved to the North or to the South), the whole trench would move hundreds of meters in very short time - therefore all the fighters would be crushed by the side of the trench before they could react, and the fight would be over, am I wrong?

• Moons don't "Suddenly change direction" – Paulie_D Dec 6 '16 at 15:37
• @Paulie_D: "That's no moon!" – Reinstate Monica - Goodbye SE Dec 6 '16 at 15:42
• @Wikis It's big enough to mistake for a moon...that'll do! – Paulie_D Dec 6 '16 at 15:43
• Like Paulie_D's link to the other article states, it's gravity would make it behave like a small moon, and any objects on or close to the surface would behave just like they would on an actual moon. – BlueGI Dec 6 '16 at 16:02
• “if Death star suddenly changed its direction” — sure. How would you make a Death Star change direction suddenly? – Paul D. Waite Dec 6 '16 at 17:14

## 4 Answers

If the Death Star was able to accelerate near-instantaneously to a rotational speed of 1 degree per second, then yes, the effect from the perspective of a pilot in the trench would be the trench wall smashing into them at 1.2 km/s. Which is pretty fast and as far as I can tell beyond normal human reaction times.

On the other hand, is it capable of making such a maneuver? The thing is massive and it would take an equally massive force to produce sufficient acceleration. The engines may not be capable of doing it, or the superstructure might not hold up under such forces.

Finally, Star Wars does have inertial dampeners for its ships and since the trench is technically within the surface area of the Death Star the very systems keeping all the personnel from pancaking against the nearest wall every time it maneuvers might keep the rebel fighters in their relative position as well.

## Ships in Star Wars likely use a combination of manual and autopilot control

We have never received much detail on exactly how vessels are controlled in Star Wars. We see pilots using control columns, but then there are also dedicated firing controls (such as in Anakin's Naboo starfighter in Phantom Menace), and ships are known to be operated both under autopilot and manual control. Needing to take your hands off the stick in combat in order to fire should be a suicidal move, but the Naboo pilots didn't seem to have a problem with it. This is suggestive.

Very likely, the X-Wings - and other fighters - use something similar to a modern aircraft's Fly-by-Wire system. There is no direct connection between the flight controls and the control surfaces (or probably thrusters or repulsorlift generators in Star Wars ships); instead, pilot control movements are passed to flight computers, which trigger the appropriate actions to achieve the result the pilot demands. This can significantly reduce the demand upon pilots by, for example, controlling the ship through standard evasive manoeuvres while the pilot concentrates on his gunnery - or, conversely, the pilot can control the ship, trusting the computers to take the shot when it's lined up.

In all probability, computers - like the Astromech droid in each Rebel ship - are providing constant trim commands to the fighters' manoeuvring systems to compensate for things like the rotation of planets, space stations, or, of course, Death Stars. If the Death Star tried to splatter the trench running fighters by simply rotating itself, the fighters would easily be able to detect and compensate for the change, likely without the pilots even noticing.

I'm of the opinion that since the Rebel fighters were flying so quickly, if the Death Star were to be rotationally accelerated, the rotation might not have even been noticed. Likely either it was quite difficult to fly inside the trench and the pilots were very skilled with their crafts, making the rotation appear simply as a maneuvering difficulty, OR the fighters were under autopilot, maneuvering based on the position of the walls, in which they would have transparently accounted for the rotation. Either way a slow rotational acceleration wouldn't have been noticed.

Remember, the station is very massive, so it would have a lot of inertia. It would likely not be capable of the kind of quick acceleration required to interfere with the flight path of a small single-man fighter. Additionally, shifting the whole Death Star all of a sudden would have the potential to upset all the personnel and equipment inside. Yes, I know it creates its own gravity, but that doesn't change the fact that everything inside the station has its own inertia and therefore has the potential to shift or fall or be damaged somehow. (And you'll screw up your gunners' aim.) I feel it's a risk that the commanders wouldn't have wanted to take.

Short answer: no, because physics says so.

Explanation: Each celestial object can be looked at as a system (an expression) with it's own properties: mass, speed, rotation speed etc. Earth has those properties, Solar system has those as well (only the numbers are BIGGER). Let's assume a fighter is a system also (it has same properties, after all). Fighter must adjust it's parameters to the bigger system - Death Star in this case - which is done by entering it's gravitational field first, atmosphere second (in other words: it will slow down and heat up from atmospheric friction and will be bound by gravity). At this time it becomes a part of the larger system and enters relational relation. It will move only in relation to the Death Star's surface, but from outside they both will travel through space at same speed, rotation etc. Fighter as part of the system is subject to changes with those just like everything else. So if Death Star would start to rotate faster, fighter will also, as it's moving through the atmosphere but ALSO WITH the atmosphere. Obviously there will be stronger Coriolis effect, affecting the fighter, but on the whole... It wouldn't be a problem, even increasing rotation speed by order of magnitude (or more).

And yes - Death Star entering the solar system (any) would have to adjust to it as well. However, this is a bit different effect than simple atmospheric braking... It's called frame dragging and it's really cool, especially around heavier stars. But never mind that. Just a fun fact.

Never mind also the fact that rotation speed of a celestial body affects it's shape... Yes, Earth is not round. It's a geoid, flatter on the poles and wider at the equator. That is why gravity is not uniform across the globe's surface. Had the Death Star started rotating much faster than earlier it would become more flat as well. Won't even speculate what would happen to the thrench then... Another fun fact only.

As a side note: increasing rotation speed would also decrease gravitational forces (by increasing upward acceleration), so fighters would be faster and more nimble, too... Yet another fun fact.