Images from the robotic craft show what appear to be liquid droplets growing, merging, and dripping on the lander's leg over the course of a Martian month.
What's This? SHARE Digg StumbleUpon Reddit RELATED Mars Water Discovered, "Tasted" by Lander -- A First Snow Falling on Mars "Seen" by NASA Lander "My Mars" by Ray Bradbury Phoenix landed near Mars's north pole last May, and several "self portraits" taken to assess the craft's health show material spattered on the legs.
This substance is probably saline mud that splashed up as the craft landed, study leader and Phoenix co-investigator Nilton Renno of the University of Michigan told National Geographic News.
Salt in the mud then absorbed water vapor from the atmosphere, forming the watery drops, Renno said.
The water can stay liquid even in the frigid Martian arctic because it contains a high amount of perchlorates, a salt "with properties like the antifreeze used to melt snow here in Michigan," said Renno, who will present the work next month at the 40th Lunar and Planetary Science Conference.
Finding liquid water under these conditions carries possible implications for Mars's habitability, the scientists say.
Dripping And Shrinkage
Renno admits that the images showing droplets are not high enough resolution to examine small details.
He also notes that instruments on board Phoenix meant to look for liquid water near the surface didn't find anything.
But he and his team are convinced that what they are seeing matches the behavior of liquid water.
"As it cooled down toward the end of the mission and we're seeing the formation of frost everywhere, the drops almost disappear," he said.