Particle synthesis was a technology which enabled the creation of artificial environments, in much the same way as holograms, but much more advanced and difficult to detect. In 2374, Arturis utilized particle synthesis on the USS Dauntless, in an effort to fool the crew of the USS Voyager into believing that the vessel was of Starfleet origin. (VOY: "Hope and Fear") In 2375, Species 8472 utilized particle synthesis in combination with holographic projections to recreate Starfleet Headquarters in their terraspheres, with which to train operatives to infiltrate Starfleet. (VOY: "In the Flesh")