This graph presents simplified data from overnight measurements by the Thermal and Electrical Conductivity Probe on NASA's Phoenix Mars Lander from noon of the mission's 70th Martian day, or sol, to noon the following sol (Aug. 5 to Aug. 6, 2008).
The graph shows that water disappeared from the atmosphere overnight, at the same time that electrical measurements detected changes consistent with addition of water to the soil.
Water in soil appears to increase overnight, when water in the atmosphere disappears.
The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.
Image NASA/JPL/University of Arizona