The scientific team that is investigating the images sent by NASA's Phoenix Mars Lander said that a view of the ground underneath the lander adds to evidence that descent thrusters dispersed overlying soil and exposed a harder substrate that may be ice.

The image received Friday night from the spacecraft's Robotic Arm Camera shows patches of smooth and level surfaces beneath the thrusters.

Horst Uwe Keller of Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany said that the image suggests that there is a an ice table under a thin layer of loose soil.

Peter Smith, principal investigator for Phoenix from the University of Arizona, Tucson explained that the scientists were expecting find ice within two to six inches of the surface
"The thrusters have excavated two to six inches and, sure enough, we see something that looks like ice. It's not impossible that it's something else, but our leading interpretation is ice," he said.

Mars is a vast desert where water is not found in liquid form on the surface, even in places where mid-day temperatures exceed the melting point of ice. One exception may be fleeting outbreaks that have been proposed to explain modern-day flows down some Martian gullies. Previous Mars missions have found that liquid water has persisted at times in Mars’ past and that water ice near the surface remains plentiful today.

Water is a prerequisite for life, a potential resource for human explorers and a major agent of climate and geology. That’s why NASA has pursued a strategy of “follow the water” for investigating Mars. Orbiters and surface missions in recent years have provided many discoveries about the history and distribution of water on Mars - such as minerals that formed in wet environments long ago and liquid flows that are still active today in hillside gullies.

Researchers have equipped Phoenix to look for answers to many questions posed in advance about water and habitat. However, if previous interplanetary missions are an indicator, some of the most important results from Phoenix may be surprises that raise new questions.