What happens when there are no asteroids at range one?

"At the end of the Activation Phase, this device detonates. When this device detonates, choose 1 obstacle at range 0–1. Each ship at range 0–1 of the obstacle suffers 1 [hit] damage. Then remove that obstacle." (Device Rules, p.20)

So the bomb still "detonates" and is removed, but has no effect on anything.