I recently asked how Starfleet sensors detect life signs and previously someone asked how Starfleet sensors receive information faster than light.

In the answers to my question (in the first link), there are references to points like watching for respiration and echoes or sounds. In the second link, there are comments about how subspace is used.

But this still leaves something open: How do the sensors actually work? Today we can "scan" things by radar or sonar or even lidar. But all of these involve sending out a beam (or a sound) and studying what comes back. In short, we have to work with reflected information.

But in The Enterprise Incident Checkov is able to find Spock on a Romulan vessel, where they would certainly be blocking any incoming electromagnetic beam that would be used for active scanning. Also, the Commander's quarters (or any quarters) are not likely to be directly up against the hull, where vibrations could be easily detected.

And when they're scanning a planet, that would mean the sensor beams (light, radio, or anything else in the EM spectrum) would have to be reflected back to provide information. That would mean that to scan a city, the sensors and computer would have to send out beams that detect and are reflected back by the outside of the building, but are also reflected back by the life forms in the building, as well as everything else in the building.

This would be true of scanning a spaceship, too. The sensor beams would either be reflected back by the hull or they'd penetrate. If they're powerful enough to penetrate the hull, then they'd go through a lifeform inside and not be reflected back.

So what do Starfleet ships use to read information about what is inside other ships or behind objects (like in buildings) or what's on the parts of a planet that aren't directly in their line of sight?

  • 5
    Questions like this make me laugh at people who call Star Trek "hard" science fiction.
    – erdiede
    Feb 18, 2012 at 22:13
  • 2
    Sensors today need not "send out" anything. They can be completely passive, like radio telescopes, or microphones.
    – Sam
    Feb 18, 2012 at 22:40
  • @Sam - ... or Mark I eyeballs Feb 18, 2012 at 23:12
  • 12
    How do Starfleet Sensors Actually Work? Very well, thank you. Feb 18, 2012 at 23:36
  • 2
    They run on liquid technobabble. Feb 20, 2012 at 18:29

2 Answers 2


I highly recommend picking up a copy of the Star Trek: The Next Generation Technical Manual, which answers these types of technical questions. From the same section that answered the life signs question:

Planetary surface analysis. A broad range of short-range sensors provide extensive mapping and survey capabilities from planetary orbit. Besides high-resolution optical and EM scanning, virtual neutrino spectrometers and short-range quark resonance scanners provide geologic structure analysis.

The same section goes on to describe the long-range sensors of the Enterprise-D, which consists of a package of both active (i.e., like sonar) and passive (i.e., like human eyesight) EM, subspace flux, gravimetric distortion, thermal and neutrino imaging scanners.

In a nutshell, sensors aboard starships work just like sensors work in real life, just with some extra technobabble. When a starship wants to scan something passively, it uses its neutrino sensors. Otherwise, it uses its array of various active scanners that can see well beyond visible light (and even well beyond normal spacetime).

Why neutrino sensors? Neutrinos have the distinction of being some of the most weakly interacting matter in the Universe: they can pass through nearly anything without any problems. For example, a cloud of neutrinos can pass through the Earth without losing much of its mass.

While a neutrino sensor wouldn't be especially powerful, it would provide at least some information even through the thickest of barriers (like planets, starship hulls, and walls).

  • Is there a similar manual available for other Star Trek series?
    – Iszi
    Feb 19, 2012 at 1:22
  • @Iszi There's one for DS9 that isn't very good and the one for Voyager was never published.
    – user366
    Feb 19, 2012 at 1:34
  • No love for TOS or ENT?
    – Iszi
    Feb 19, 2012 at 1:37
  • @Iszi while writers' bibles almost certainly existed for those two series, there's no evidence of technical manuals for them. The Star Trek Encyclopedia covers some technical details from TOS, but nowhere near the detail as the technical manual and was published before Enterprise. Ships of the Line covers some technical details of Enterprise, but again, nowhere near the detail in the technical manuals. Additionally, it's not considered canon.
    – user366
    Feb 19, 2012 at 1:40
  • 3
    I can't believe I'm the first one to mention the original technical manual, the Star Fleet Technical Manual: amazon.com/gp/product/0345340744 It's far less detailed and has less technobabble than the TNG version, but it's pretty much required reading if you're a Trekkie. Feb 19, 2012 at 4:15

In much the same way real ones do. Starfleet ships are covered in large sensor pallets. These installations collect information based on how they're designed to interact with phenomena and energy. They work no different than real world sensors but presumably are computerized and more sensitive and powerful as well as able to detect the fictitious particles/energies of Star Trek physics. To detect certain things real world sensors are based on certain materials. For example to detect infrared radiation; Sensor contains a device coated with Indium Antimonide which interacts with infrared waves and sends the data to a aperture, display or computer. So it's a safe bet the ships sensor pallets are nothing but a HUGE network of different types of sensors integrated. Just like we have sensors and experiments on probes we send into space, so do they or the integrated sensors on real navy ships. For detecting things in the entire EM spectrum (radio waves, microwaves, gamma waves), particle detection such as muons or neutrinos, anti-matter, gravitational waves. The Ships computer converts that data into relevant information or into visual capacities we can interpret (Viewscreen) enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.