[sangnoir]

> Speeding up does not work, that'll just put it in a higher orbit

Speeding up doesn't raise the orbit; it makes it (more) elliptical while still intersecting with the old orbit (shared with neighbouring satellites)- you need at least 2 maneuvers to raise an orbit. You're also assuming a perfectly pro-grade acceleration. In an explosion, different pieces go in different directions, I suspect there is a vector that results in faster speed in the same orbit, but I'm no rocket scientist.

[sangnoir]

Correcting an inaccuracy in the last sentence I introduced in an edit: Kepler's laws means you cant have different velocities in the same orbit - bit its possible for an explosion to cause a projectile to intercept a satellite that was ahead of it in a new orbit.