NASA just announced (Monday, September 29, 2008) through its news release, “NASA Mars Lander sees falling snow, soil data suggests liquid past,” that Phoenix has detected snow falling from about 2.5 miles (4.2 kilometers) above the landing site of the spacecraft.

The snow is falling from Martian clouds within its atmosphere

The NASA website of the Phoenix Mars Lander mission contains more information.

However, Phoenix has shown that the snow is vaporizing before it reaches the ground.

Canada's York University professor Jim Whiteway, who is the lead scientist for the Meteorological Station onboard the Phoenix spacecraft, stated, “Nothing like this view has ever been seen on Mars. We'll be looking for signs that the snow may even reach the ground." [NASA]

A laser instrument onboard Phoenix, which is designed to analyze the atmosphere and surface of Mars (along with their interactions), gathered the data, which made this stunning announcement.

The NASA article also announces more evidence for a watery past on the planet Mars. Please read on.

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This same NASA media release also announced that the Phoenix craft also has found calcium carbonate in soil samples on Mars. Such a discovery provides direct evidence that substances interacted with water in the past.

The discovery was made using Phoenix’s Thermal and Evolved Gas Analyzer (TEGA) and the wet chemistry laboratory of the Microscopy, Electrochemistry and Conductivity Analyzer (MECA), both that are attached to the Phoenix robotic arm.

America's University of Arizona professor William Boynton, who is the lead scientist for TEGA, stated, "We have found carbonate. This points toward episodes of interaction with water in the past." [NASA]

The mass spectrometer on the TEGA found a match of the temperature at which calcium carbonate is decomposed and the temperature at which carbon dioxide gas was released from soil samples (which indicates decomposition of calcium carbonate).

In addition, the microscopy part of the MECA instrument measured a concentration of calcium that was identical to the concentration for a solution buffered by calcium carbonate.

The NASA article states, “Both TEGA, and the microscopy part of MECA have turned up hints of a clay-like substance.”

Michael Hecht, MECA lead scientist, states, “We are seeing smooth-surfaced, platy particles with the atomic-force microscope, not inconsistent with the appearance of clay particles.”

The Lunar and Planetary Laboratory at the University of Arizona head the Phoenix mission program. NASA’s Jet Propulsion Laboratory in California is directing the program.

The Mars mission of Phoenix is also a partnership of universities in Canada, Denmark, Germany, Switzerland, the United Kingdom, and the United States, along with the space-related agencies of the United States (NASA), Canada (Canadian Space Agency), and Finland (Finnish Meteorological Institute).

Scientists with the Phoenix spacecraft hope to be able to extend its mission through mid-November 2008. Its limitation will be the amount of sunlight hitting its solar arrays.

As the landing site of Phoenix gets into the colder season on Mars, less sunlight falls on its solar arrays. Eventually, not enough solar energy will be produced and converted to electricity to operate the spacecraft.