Sensor
The term sensor, also referred to aboard starships as subspace sensors or sensor probes, was used to refer to any device that was used to scan, record, or otherwise observe any aspect of an environment surrounding a starship, space station, or person. This could be as simple a device as a manual camera or light sensor, or as complicated as the myriad devices designed to scan many aspects of the matter and energies of subspace, space, time, and stellar bodies that make up all of existence.

Sensor probe 
The term "sensor probe" was used to indicate sensors used for probing. (; ) Lieutenant junior grade Worf conducted a routine deep sensor probe while the  traversed the Zed Lapis sector, which indicated "no obstacles or vessels within a range of three light years." () 

However, the term also referred to a specific type of automated probe, used by Starfleet. Such a probe was launched by the  to scan Delphi Ardu IV in 2364 and to monitor a convoy used as bait for the Maquis in 2370. () The  also used such a probe to study the Jem'Hadar battleship in 2374. ()

Specifications 
Sensors of various types played roles in almost every aspect of space travel. Every type of sensor, from navigational sensors to ARA sensors, created data to be interpreted by the vessels' computers and operators. In most situations, the sensor data revealed information that was not apparent through other data-collecting means, such as visual observations. (; ; )  starships were equipped with high-resolution, multi-spectral sensors. ()

There were two basic types of sensor arrays employed: passive and active. A passive scan was less obtrusive than an active scan, and might not be detected by the subject being sensed. Sensors were divided further into short- and long-range types, and low- and high-energy types. (; )

While there are many ways to mask a sensor scan, sensor screens were the most commonly used method. () One could also mask a sensor scan with certain materials, or radiation. () Sensors can be disrupted by overloading them with information. () Sensors and communications can also be disrupted by interference from a planet's troposphere and ionosphere. (; ; ) One could also move to a position in orbit at a planet's magnetic pole to confuse sensors. () But to truly hide from a sensor scan, one would actually have to change one's molecular structure. ()

Use on vessels 
The Starfleet vessel  was equipped with a lateral sensor array. When Captain Jonathan Archer and Commander Charles Tucker III were inspecting the new prototype  ship in an inspection pod during 2151, one of the components that Archer wanted to view was the lateral sensor array. ()

Sensors were meanwhile used by the Vahklas, a  ship, which had left the planet  in approximately 2143. When Sub-Commander T'Pol was studying the Arachnid Nebula aboard the Vahklas in 2151, she was temporarily unable to scan the nebula's disodium layer, due to the fact that the transport ship's lateral sensors were out of alignment. ()

Less than a year later, all sensors at Tandaran Detention Complex 26 were overly "occupied" by Hoshi Sato aboard Enterprise, who transmitted loads of data to the facility, thereby jamming the internment camp's frequencies. This disruption allowed Enterprise to conceal a transporter beam from the ship to the facility. ()

In 2364, prior to stardate 41775, the Federation starships  and  were ordered, by a Starfleet admiral, not to scan a particular subsector with a high energy scan. ()

In early 2368, when investigating the Phoenix Cluster, the lateral sensors of the USS Enterprise-D were booked solid for planetary observation. ()

In 2370, the Romulan warbird Terix performed a sensor scan of asteroid Gamma-601 in the Devolin system with its lateral sensor array in hope to locate the . ()

An example of the accuracy of sensors was in the sensor data of the  during one encounter with the Borg. Sensor readings from the ship's active scans recorded "random subspace energy fluctuations" at various time indexes in the sensor logs. Closer examination of this data revealed the detections were not random fluctuations but communications to Seven of Nine, one of Voyagers crew. ()

The enormous capability of the USS Voyagers sensors was demonstrated on one occasion when Captain Janeway requested that Harry Kim scan space for sporocystian life-forms. Moments later, Harry reported finding a "sporocystian energy burst, approximately ten light years distant." This implies that the sensors were able to scan and analyze a volume of more than 4,100 cubic light years in about six seconds. ()

Types of scans
antiproton beam
autonomic response analysis
geological scan
high-resolution scan
passive high-resolution series
internal scan
long range sensor scan
magneton scan
navigational scan
multiphasic scan
subspace differential pulse
inverse tachyon pulse
virtual positron imaging scan

Background information 
In a section of ultimately unused dialogue from the first draft script of , Vulcan sensors were established as being more technologically advanced than Starfleet sensors at the time of the episode's setting (in 2151). One function that Vulcan sensors were said to be capable of was detecting a Nausicaan bio-sign whereas Starfleet sensors were notoriously incapable of that.

See also 
 List of sensor devices
 Sensor log

External link 
 

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