The impetus for this question is that as of Rogue One, we have observed three (!) or even four (!!) instances of people or droids evading capture while out in the open in a desert with Imperial ships in orbit.

  1. R2-D2 and C3-PO on Tatooine (They are not found even though they are being searched for before they arrive at Mos Eisley. Then "These aren't the droids we're looking for.")
  2. Finn and Poe at Jakku (separately!)
  3. Jyn Erso on Lah'mu (where she evades capture by essentially running into a gully!)

All of which suggest the scanners are not capable of tracking known wide open targets at a known starting location -- a feat which is easily accomplished with today's optical satellite technology and was easily imaginable in 1977.

Yet in A New Hope, after R2-D2 and C-3PO eject from Leia's ship, we have

"An escape pod was jettisoned during the fighting, but no life forms were aboard."

which suggests at least, that it was intended that the scanners would have been capable of identifying people inside the craft. (Yes, there are other potential explanations, but this seems to be to have been the intent.)

So what gives?

What exactly are the capabilities and limitations of Imperial scanners?

(Related Did the sensors in Star Wars universe not have the ability to scan for droids?: That question is much more narrow and the given answers don't answer this question.)

  • 1
    @Praxis: here's another for you Commented Dec 30, 2016 at 4:25
  • Interesting. Modern-day satellites certainly can resolve very small images, but the question of how fast they can do it is pertinent. It might take a long time to image a significant area at resolution high enough to track a human.
    – Adamant
    Commented Dec 30, 2016 at 5:03
  • @Adamant: Yes, but in two of the cases, they have the ships to track, and in the third, they were literally standing right next to the target. So I stand by my evaluation that it was easily doable using present Earth technology. Commented Dec 30, 2016 at 5:15
  • Star Wars scanners are not able to resolve any data the screenwriter does not want them to have.
    – Werrf
    Commented Jan 4, 2017 at 13:48

2 Answers 2


Ship scanners are essentially satellites taking real-time photos from space. Ground scanners are short range movement and life form detectors-which have a stronger when detecting a group.

In episode 5, the ground droid at the start gave evidence of settlements, whereas the ship scanners only found minor evidence of possible groups of people(conversation between the admiral who gets killed later, the captain and Vader). Also in episode 5, Luke couldn't detect Yoda's/sentient life specific signature, but did detect a lot of life readings, indicating animal life across the planet.

In episode 4, the scanner brought on the Millennium Falcon didn't detect the crew in time to prevent the ambush. Also in episode 4, Dantooine didn't show signs of life from space, even if possibly camouflaged.

In Rogue One, Jyn evades capture by waiting in a hole, rescued by a friend who knew where to find her in the event of an emergency.

It seems much harder, if not impossible to detect a single person hiding, at least without the use of the Force. It's been consistent in the series that ship scanners detect movement/groups/life, and ground/short range detects movement and life signs, but will have trouble if you stand still.

  • The episode 4 thing: those are smuggling compartments specifically meant to hide illegal contraband from imperial scanners Commented Mar 11, 2020 at 15:02

I believe you are referring to the Lifeform scanner, no? I mean, Wookieepedia lists some 14 odd scanner types. Most are variations of each other.

Essentially, Scanners used for detecting lifeforms do not have wide "footprints" whilst retaining specific data such as species (in my understanding at least). The Imperials on the Executor (Vader's Super Star Destroyer) were checking for escaping Rebels. Not droids. The Empire follows a belief that droids are effectively good for menial chores, and math. I don't think they thought that the Rebels would send the all-important plans with two droids. In their oversight, they failed to scan for electronic power sources (though the pod may have helped disguise the two droids within- they may be mistaken for auxiliary power sub-systems).

As scanner (hypothetically) cannot be used over wide areas, it stands to believe that both Poe and Finn had covered enough ground between the crash radius and the scanning crew to evade capture.

The "black guard" stormtroopers that searched for Jyn were probably not equipped with scanners. I just don't think they were required to carry the gear. Not to mention that Admiral Krennic thought that a scanner was unnecessary to find a child.

If this isn't the case, then there is information we don't know, a plot hole, or the Force in action.

Oh, and FYI, imperial scanners allegedly cannot be deceived by electronic concealment methods. See Lifeform scanner for citation.


Hope this is educational, if it doesn't answer your questions.

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