How the hell did the peacekeepers crash on earth TWICE? Do they just suck at driving spaceships?
To their defense, only the first ship in The Lightkeeper crashed (the red one). The second one (blue) and the one in The Trespasser landed on Earth to investigate, but their crew got killed. Though at this point they probably see Earth like the Bermuda Triangle, a place to avoid if you want to keep your ship :p