A robot ship converting planet after planet for their own purposes, and not caring what happens to anything living there?

Planet after planet appeared on the screen, to be replaced by others, and he blinked at the result of his count.

Planet after planet swam into the ken of mankind.

Dominus was the channel by which the alien race known as "The Arcane" conquered planet after planet.

Didn't he know how the Sisterhood was being overwhelmed by terrifying numbers on planet after planet?

The nano plague was everywhere now, springing up on planet after planet.

Omnius was delivering the disease with ruthless efficiency, tainting planet after planet, despite the League's best efforts to stop the spread.

On planet after planet, human civilization had been reduced to subsistence level.

Before them the familiar solar system they'd all cut their teeth on scrolled out, planet after planet, moons, asteroids, and the tolerant yellow sun far beyond.

Planet after planet must be attacked, reduced, and garrisoned, so that the foe always fought off balance, on the defensive.