Near the start of the chapter, while the credits are still rolling, you can find this artifact along the left side of the path.
Chapter 1: Rude Awakening
When you are in the red lit Dredger Corp. offices, take the elevator and when you exit, enter the office on the right. On the ground will be the artifact.
When you reach the highway with the speeding trucks, cause the crash and then make your way to the opening on the left side.
Chapter 2: On Your Own
After the intro scene to the chapter, continue through the ship until you have gone down the stairs and through the door on the right. Once through, you will come to a curved hallway to the right side. Follow it all the way to the end and you will find the artifact on the ground on the right side.
You will need to move a couple boxes to enter the C.A.G. Briefing Room. When you do, go inside and follow the stairs up and then down to the far side. On the stage at the front of the room, you will find the artifact.
Chapter 4: History’s Ember
EARTHGOV ARTIFACT 1
After the cut scene with Isaac, Carver, and the wall scribbles, go to the right of the window and there will be a bookcase. The artifact will be on the ground.
EARTHGOV ARTIFACT 2
Found during Optional Co-op Mission C.M.S. Brusilov
S.C.A.F ARTIFACT 1
When you first reach the docking bay to the Roanoke, look down into the gap before the docking doors and you will see this artifact floating there.
S.C.A.F ARTIFACT 2
In space, outside of the Greely, there’s another part of the large ship that has the numbers B1348 on the top of it. Go to the far side of the debris and there will be a door on the side that can be opened. Inside you will find the artifact in the corner.
S.C.A.F ARTIFACT 3
Outside of the Brusilov, to the left of it, there is a large piece of debris that has a large 6 on it. You can find a door that can be opened on the broken side, behind the 6. Enter to find the artifact on the right, on a table next to a computer.
(Optional Mission: C.M.S. Greely) On Greely, when you enter the room with purple lights to the right side, go to the far right corner and find this under the purple light.