Explorator Fleet
The Explorator Fleets are fleets sent by the Adeptus Mechanicus to explore less-known parts of the galaxy.
Their primary mission is to find lost technology, especially a working STC system (though printouts are also welcome). Often, they find other things, like new worlds and civilizations, or worlds with which contact had been lost centuries before, or Forge Worlds founded by a previous expedition. Often they find danger, which is why they bring along a detachment of Skitarii, just in case.
Explorator Fleets tend to be crewed by the most curious of tech-priests, which means that when they find ancient tombs filled with impossibly advanced technology, they tend to poke around a little too hard and a little too deep, which wakes up the Necrons and causes lots of death (this happens in at least two of the Ciaphas Cain stories). It's a seriously endemic problem, probably compounded by the fact that some tech-priests worship the Necrons as angels of the Omnissiah.
