QUESTION: Water infiltration into Mars soil What is the behavior of water infiltrating into the Mars soil? Is it the same as on Earth? ANSWER from Jeff Plescia on June 28, 1999: The basic hydrologic laws will be applicable to Mars. The only difference will be in a lower gravity. We really have no data on the subsurface physical properties of the martian soil. In fact it's not all together clear how the material forms. The information that we have on the physcial properties was published in the December 1997 Science issue on Pathfinder and USGS Prof Paper 1389 on Viking. Jeff Plescia U. S. Geological Survey Astrogeology Program