> Some people are assuming it has fins, but none are visible in diagrams.
Many years ago I saw a concept of a guided machine gun bullet in a "scientific" magazine; the concept involved steering by a mechanism that moved a lump of mass within the bullet around.
How in the world does that work? Bullets spin at ridiculous rates; some 3000 RPS. At long distances it'll have made over 10k revolutions before it hits the target!
Many years ago I saw a concept of a guided machine gun bullet in a "scientific" magazine; the concept involved steering by a mechanism that moved a lump of mass within the bullet around.