These mud cracks are additionally labelled "dessication cracks" and suggest previous existence of water. The phenomenon of cross-bedding might also demonstrate prior water locations on Mars a very long time ago. This pattern forms when water moves, sometimes with more force than slowly, near the edge of pooling water or larger lakes, although also this pattern might prove the result of sediment blown around by wind during a dry period of time, or suggest the existing for both types of natural phenomena.
Mud cracks found on Mars absolutely must be a positive correlation to the presence of water, either in the ancient past, or potentially currently, beneath the planet's surface. There is no other way for a mud crack to be formed, unless there was mud present in the first place that became dried out and then cracked. Dirt plus water equals mud.
Yes, NASA has gathered a great deal of evidence of past water on Mars. This newest discovery revealing mud cracks signals the possibility of water. The questions are many. How long ago did water exist on the planet? Where did it go? Is there any underground? Could it be a liquid other than water? Further explorations will yield more answers.
NASA's recently released data pertaining to mud cracks on Mars is likely very good evidence of a correlation that water once existed on the planet. While some planets have a liquid on them even though it is not water, the research already conducted into Mars makes it very likely that it was once covered with water.