How is it tangential? It's directly related. The satellite is moving in a straight line at a specific speed. The explosion does not negate that speed, rather it just applies a momentary bit of acceleration/deceleration along a new vector. So unless an explosion can provide more acceleration that can null out the original object's speed, the pieces will remain in orbit. That's just how fast orbital speeds are, and it took a bit for that to click
But we’re worried about the pieces hitting another satellite in goe stationary orbit further along the orbit. A single burn can’t do that in a direct way because there is no direct path between two satellites at the same orbital distance (speed)
