If we discover another planet hospitable to humans, would it be likely they would have evolved the same as us? If Jesus (the creator of the universe) made all the worlds and inhabitants in his image, surely they will have known of his death on the cross.
Besides, the sacrifice for sin is eternal and would encompass all his creations. No inner-planetary missionaries would be needed for they will already have the WORD. If they do worship other gods, I wonder whose god will kick butt over the other. I’m sure it will be the ones with the highest level of revealed advances designed with the sharpest steel, the farthest bullets, and the best bombs. The god with the best guns will be THE GOD—same as always.
Imagine if they are a bit primitive how much success we could have preaching to those poor burdened souls that have never heard of Jesus. We could make them super happy—like us—and the Muslims of course. Sharing our economic models would be a real treat for them too.