Orders were to take the ship to the nearest solar system to Earth's. It had no habitable planets and therefore no intelligent life was expected to be found. They would drop a communications buoy and probes to explore the planets and then return. Unfortunately for their well laid plans, it was an inhabited solar system. The ship hadn't even breached 'air space' of the solar system when it was captured in a tractor beam that dragged them in like a spider reeling in its prey.
And the inhabitants didn't seem to grasp what 'we come in peace' meant.