A paper published in Science presents the data used to determine the existence of an underground Martian lake. The scientists took information from the radar instrument aboard the ESA Mars Express between May 2012 and December 2015 and came to the conclusion that there is a body of salty water under the south pole of Mars. If this is indeed liquid water, it would have to be extreamly salty to be a liquid at the Marian poles.
Before everyone gets all excited, this is indirect proof of water, not direct proof. It is a huge step in finding water, as we now know where to look! The next step would be to send a drill to look for direct confirmation that there is water. The InSight mission has a drill on it, but it’s mission is seismic, so it won’t be testing for water. However, the mission uses the same lander chassis as the Phoenix mission in 2008 that landed in the north pole. Using the leanings from InSight and Phoenix, we could have a water drilling lander up and running in no time! 🙂
Water is essential to any human mission to Mars. It’s also a building block for life as we know it. In Russia, scientists drilled into the ice at lake Vostok to a depth of 3,400km. The found life in ice that had been sealed off from the atmosphere for millions of years. It’s completely possible that there are tiny bacteria locked away in this Martian lake…
I don’t think it’s going to be a hostile zombie parasite like the movies. I’d settle for something harmless.