If I take a wild guess (into the next 50 years), we probably will be able to land on Europa. After collecting dirt and water, we found nothing. However, scientists didn't give up on it and debate life could be existed in deep ocean, which is way deeper than what we can go even on Earth. There you go: we have to go far across space and end up swimming really deep. Too many technological barriers. It'd be even more disappointing when we actually find out living organisms, then they look so similar to what we already have on Earth. Again, my "wild guess"