Phoenix Conductivity Probe after Extraction - Sol 99 (natural colors; credits: NASA)

Caption NASA:"NASA's Phoenix Mars Lander inserted the 4 needles of its Thermal and Conductivity Probe into Martian soil during the 98th Sol of the mission and left it in place until Sol 99 (Sept. 4, 2008).
The Surface Stereo Imager on Phoenix took this image on the morning of Sol 99 after the probe was lifted away from the soil. This imaging served as a check of whether soil had stuck to the needles.
The Thermal and Conductivity Probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

The probe is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments".