Based on data acquired by NASA’s Galileo satellite, astronomers think that the oceans beneath Europa’s icy exterior are likely 2—3 times more in volume that that of water of all the oceans on Earth! Not 2—3 times more proportionally, 2—3 times more in total volume. Jupiter’s little moon is packing all that H2O and scientists say that there could be a significant chance of it harbouring life!
Even if it doesn’t think of all that water; we’d have a possible source to go to replenish our stock. Ofcourse no one knows for certain how thick the ice could be, could be a few miles thick, and it might be extremely tasking to dig deep down into it and arrive at the oceans. But if it could be done, exploring the oceans below would certainly be amazing and who knows what we could find. And even if there no alien lifeforms there just exploring the waters would be so cool. I would love to be able to see that happen in my lifetime. Hell, I’d kill to be able to go there myself and be part of the first landing party.
The image above is from io9.com comparing all the water on Earth made into a globe on the right vs all the water on Europe made into a globe on the left. See the size difference?