NCD2539
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NCD2539 is a location of space that the Fleet knows that Cylon ships use as a supply route. The complete designation is "The Region of NCD2539 Above/North."
Battlestar Galactica intentionally visits this area to lure Cylon forces, including a Resurrection Ship, into the area. The Colonials intended to kill their Humanoid Cylon prisoners, whose consciousnesses would download and infect the Cylon populace with a human virus with a bioelectric pathogen that would effectively annihilate the Cylon race.
The objectives of the Battle of NCD2539 were defeated by internal sabotage (A Measure of Salvation).