Water on Mars any point in the year but would be ideal for solid carbon dioxide. The carbon dioxide melting in the warmer summer would yield liquid carbon dioxide which would then form the gullies. Even if gullies are carved by flowing water at the surface, the exact source of the water and the mechanisms behind its motion are not understood. The dry gullies are deep grooves etched into the slopes that are there year-round. There are many other features on Mars, and some of them change seasonally. In August 2011, NASA announced the discovery by undergraduate student Lujendra Ojha of current seasonal
Mars habitat Fingal's Cave and noted the increased protection from high-energy radiation below ground. On the other hand, the issue of the difficulty of sending digging robots that must construct the habitat versus landing capsules on the surface was also noted. An alternative may be to build above ground, but use thick ice to shield from radiation but with advantage that it lets visible light in. In 2015 the SHEE project noted the idea of autonomous construction and preparation for Mars habitat versus human construction. In early 2015 NASA outlined a conceptual plan for three stage Mars habitat design and construction award