A Nanite projector is a device used to deploy microscopic robots to a target area for various purposes.
Based off technology brought over to the Koprulu Sector by the UED, the projectors are an modified version of the ones used by Medics. Depending on programming, the nanites can either be used to repair or disintegrate biological organs or mechanical structures. Each nanite payload is conveyed via a low level pulse or stream of energy that is enough to power the robots, but not enough to damage their target (Star Trek - Voyager: Nanoprobe; Team Fortress 2: Medi Gun).
Nanite projectors can be equipped to various vehicles, spacecraft, and other types of machines that can provide enough power and materials. Recently, the Terrans have been using them mostly in Science vessels and utility ships to help speed up critical repairs to high priority units and structures.