Why the Phoenix Landing Site is Perfect

By Nancy Atkinson - May 27, 2008 at 5:08 PM UTC | Missions
permafrost_mars.jpg

Phoenix's landing site may look flat and uninteresting. But actually, the site is perfect, and is exactly what the Phoenix science team was hoping for. You see, Phoenix is actually more interested in what is

below

the surface. From one of the first images sent back by Phoenix, a view of Mars' surface at this site reveals a landscape familiar to polar scientists on Earth: a pattern of interlocking polygon shapes that form in permafrost that freezes and thaws seasonally. These polygon patterns were seen in orbital pictures taken by the Mars Reconnaissance Orbiter, as well as other spacecraft, and these polygon shapes are part of the evidence that Mars’ polar regions harbor large quantities of frozen water.

This pair of images above shows the similarities between the surface of Mars where Phoenix landed (top) and permafrost on northeastern Spitsbergen, Svalbard (bottom) an archipelago in the Arctic Ocean north of mainland Europe, about midway between Norway and the North Pole. The polygon patterns in the permafrost form when the upper parts of the ground thaw and refreeze from season to season. The ground contracts in the winter cold, creating small spaces that fill with melted water in the summer. When winter returns and the water freezes, it acts like a wedge, enlarging the cracks.

The only difference in these photos is the Earth image shows water on the surface, and on Mars, water couldn't pool on the surface because the low atmospheric pressure would cause any water that might bubble to the surface to sublimate. But the thaw/freeze process could presumably occur beneath Mars' surface with far less water.

And why is this so interesting? On Earth, permafrost, glaciers, and other frozen environments can preserve organic molecules, bacteria, and fungi for hundreds of thousands, even millions, of years. The Phoenix spacecraft has scientific instruments that will dig into the frozen ground of the Martian Arctic, vaporize the soil sample, and analyze the chemistry of the vapors. Scientists hope to learn whether ice just below the surface ever thaws and whether some chemical ingredients of life are preserved in the icy soil.

That's why Phoenix's landing site is perfect.

Original News Source:

NASA Earth Observatory

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com