The act of bombarding a planet, moon, or other such stellar object from orbit around it, often with devastating effects. Either traditional weapons (Nukes, lasers, etc) or kinetic energy weapons can be used.
A necessary precursor to the invasion of a planet, unless it lacks any military infrastructure. It is the next step after air strikes in the evolution of bombardment.
It is safer (for the attacker) than previous incarnations of bombardment because it is much harder to attack something in orbit than it is for them to attack you.