Tachyon scan
A tachyon scan, also known as a tachyon sweep or tachyon signal, involved a starship emitting a tachyon beam at a particular location in an attempt to detect cloaked vessels by finding tachyon emissions given off by a cloaking device. Although a tachyon scan would detect most vessels using a cloaking device, its range was relatively limited but could be vastly increased by setting up a tachyon detection grid. (; ) This technique could also be used to scan quantum singularities. ()

In 2373, Lieutenant Tuvok suggested that the  begin a tachyon sweep of a class 17 nebula in the Delta Quadrant. Tuvok explained that it would reveal the existence of cloaked ships, as he believed Voyager should be careful while being so close to Klingon space, despite the fact that Klingon Empire was on the other side of the galaxy. Tuvok's brain was infected at the time with a memory virus, which had him confuse the present with an altercation that Kang and the Klingons had with the , a starship Tuvok served on in 2293, at the Azure Nebula. The class 11 nebula bore a superficial similarity to the class 17 Voyager was near. ()

However, the Remans were able to remedy tachyon scans by developing a highly-advanced cloaking device that produced no tachyon emissions, rendering the user completely undetectable to all known scanning methods. Such a cloaking device was incorporated in to their massive warbird, the Scimitar. ()

See also
Long-range tachyon scanner
Tachyon detection grid

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Scans