Why didn't Vader use the Force to assume command of the Death Star and overthrow the Emperor?

[Mastr Blastr]

Seems simple enough. "Tarkin (or Jerjerrod), I am now in command of this battle station."

"You are now in command of this battle station."

"Set a route for Coruscant and open a comment channel to the Emperor stating the terms of his surrender."

"I will set a route for Coruscant and open a command channel stating the terms of his surrender."

[Ralin]

1) Tarkin is strong-willed and could plausibly resist it.
2) Lots of people are involved in piloting the Death Star and they can't be trusted to obey orders like that blindly. Trying to control them all and suppress any mutinies would have taxed Vader's abilities to the breaking point.
3) Also there were like hundreds of thousands of stormtroopers on board and 'stopping Vader if he gets ideas' is probably part of the reason why they were there.
4) Vader is emotionally and psychologically damaged. Palpatine has all sorts of hooks in him.
5) He probably didn't think it was enough of a weapon to overthrow the Emperor. Remember how dismissive he was of the 'technological terror?'
6) Anything Vader can do with the Force Palpatine can likely counter. Especially if there's an open comm channel to help him focus.

[Lord Revan]

7) there's probably a system within the Death Star that prevents the commander from getting "ideas" that emperor can activate should the need arise and Vader probable knows about this, it could something as simple as the Emperor having override command on the Death Star hard coded into the system.

While I suspect any enlisted imperials would obey without questions, Palpatine isn't stupid, arrogant yes but not stupid, he's smart enough to live and work with high ranking Jedi for years and you can't rely on the shroud of the Dark Side for that after all it only weakens the Jedi's ability sense you thru the Force it doesn't remove their ability to make deductions the old fashioned way. Because of this it does seem like that Palpatine has thought of the possibility of the CO of the Death Star going renegade and thus made plans to prevent that.

[Gandalf]

Also, Vader seemed pretty psychologically broken at that point. Would it have even occurred to him to rebel like that?

[Shroom Man 777]

Force mind tricks seem to work best when the suggestions aren't as obstructive, "these aren't the droids you're looking for" in a way is like a slip or brain fart. Barring TFA's example.

Also Vader only really plans to usurp Palps when he realizes he has family (and thus Palps lied about Padme's death etcetera).

[Lord Revan]

Force mind tricks seem to work best when the suggestions aren't as obstructive, "these aren't the droids you're looking for" in a way is like a slip or brain fart. Barring TFA's example.

Also Vader only really plans to usurp Palps when he realizes he has family (and thus Palps lied about Padme's death etcetera).

There's also probably the fact the Stormtroopers in ANH were in their mind looking for an excuse to not inspect everyone who came thru their check point so they could go on break or something similar, they're just humans after all and the task they were doing was probably really boring.

Based on what I've seen a stronger command could get thru but it would be much harder and more likely to cause the victim to act unnatural.

If we look at the cases on Mind Trick in the OT and PT the victim often acts normal apart from mumbling to themselves while the TFA example the First Order Stormtrooper acts robotic and unnatural suggesting what Rey used wasn't a normal Mind Trick but closer to mental domination.

Could Vader do this possibly, could he do at scale of the Death Star crew mostly likely not even if he wasn't mentally and physically broken, even if there were examples of Sith dominating minds on the scale of a whole crew of a ship in the Legends

[Ralin]

Heck, even ignoring all that, why wouldn't Vader wait until the Death Star had been field tested a few times and the Rebellion was decapitated so he doesn't have to deal with it later? The guy had waited a couple decades. Clearly he's learned to bide his time with Palpatine.

[Gandalf]

If Vader somehow rides the Death Star to Coruscant and decides to overthrow the Emperor, how does he then get the loyalty of the Imperial government? Or the military? Loyal public servants like those in Andor may not all go along if Vader's pet assumes the throne.

Maybe Vader just liked his spot of Chief Mouser. Then Luke came along and messed it all up.

[Solauren]

We know from Legends there were hard-coded passwords and over-rides being used by the Emperor's agents. Mara Jade used them.
Even Grand Admiral Thrawn didn't know about them.

We also know from Legends Palpatine could create Force Storms, and even Wormholes.

It's possible Vader was of mind "Well, if I take this thing over, the Emperor probably has a dozen fail safes in place. Even if I dealt with all those, that gives him more then enough time to get close enough to use a Force Storm to rip this thing apart.

On the plus side, with the Death Star running around, and the Senate gone, we'll have more time to devote to Force training. Then I'll get powerful enough to deal with him face to face, and then I can take over the Death Star."

Also, it's been noted in some sources that Vader hated the Death Star.

[RogueIce]

In ANH, Vader was sufficiently broken/cowed that the idea of betraying Palpatine wasn't even there. Even if he could have broken Tarkin's will (extremely unlikely) or simply killed him and declared himself in command, he had no motivation or desire to do so.

In ROTJ, Vader may have been open to the idea (if he could get Luke on his side) but if you'll notice the Emperor had a throne room there - which for all we know was going to become permanent, so Vader trying to dominate Jerjerrod would be for naught as Palpatine would be right there to stop him.

[Galvatron]

The Death Star would have merely become Vader's second prison (the first being his suit).