Messenger mission to Mercury has used 2 instruments to confirm water on that planet with the help of the Arecibo radio telescope here on Earth. It seems that ice water is able to exist on Mercury in deep craters near the poles of the planet. These craters never see sunlight and thus never reach the excruciatingly hot temperatures that would melt the ice almost instantly. Since there is no atmosphere on the planet, the heat on the day side is not distributed through the atmosphere to the polar regions. This unexpected discovery is mirrored by the discovery of water in the form of ice on the Moon, which has also been found in deep craters near the poles that never see sunlight.
Earth sized planet orbiting very close to it’s star. Since Alpha Centauri is our closest Star neighbor, it might even be possible to establish polar bases on that planet that would survive the extreme heat that is found on that planet. There might even be water there and that might make the first permanent base outside our solar system possible. Water is essential to us and everywhere we find it is yet another place that we will be eventually able to visit, so finding it in such a unexpected place as Mercury bodes well for the human race.