Mars Water Discovered, "Tasted" by Lander -- A First
for National Geographic News
|August 1, 2008|
NASA's Phoenix Mars Lander quenched a longtime scientific thirst yesterday when it detected water in a soil sample—the first time liquid water on another planet has been touched or "tasted."
The craft obtained water by heating an icy soil sample in its "bake and sniff" oven, called the Thermal and Evolved Gas Analyzer. "TEGA" identifies substances by heating them and analyzing the resulting vapors.
"We have water," said William Boynton of the University of Arizona, lead scientist for TEGA.
"We've now finally touched it and tasted it—and from my standpoint it tastes very fine."
(Pictures: Phoenix Lander's Search for Mars Water.)
Search for Life-Friendly Conditions
The successful sampling completes one of the Phoenix mission's core objectives—confirming that water ice does indeed exist near the Martian north pole.
Now the mission has been extended through September 30 to allow the lander to analyze that water ice and soil for signs of organic materials and for conditions suitable for life, NASA announced.
The additional five weeks of operation will cost some two million U.S. dollars.
Principal investigator Peter Smith, of the University of Arizona, reported that all of Phoenix's instruments are healthy. A troublesome short circuit problem appears to have been resolved.
"We're going to complete the science that we set out to complete," he said of the mission's extended time. "But we have lots more to explore within reach of our robotic arm."
Phoenix's landing site was chosen because orbital observations suggested the locale was rich in ice. After enduring a descent phase known as the "seven minutes of terror," the craft landed on May 25 on a solid layer of ice covered by only a few inches of sticky Martian soil.
Still, the presence of ice in the latest sample was a surprise.
Efforts to acquire larger ice samples for TEGA have been hampered by collection problems—most recently when two promising ice loads simply stuck in the scoop and could not be transferred to the instrument.
(See "Mars Lander Stymied by Ice; Like 'Scraping a Sidewalk'" [July 11, 2008].)
Unable to collect ice from the solid ice layer, the team decided to analyze a soil sample from just above it.
Surprisingly, the soil turned out to be made of about one percent water ice.
"Now we are starting analysis of what turns out to be an icy soil," Boynton said.
Tests on the Martian soil could reveal whether it has ever been in contact with melted, liquid water—a key indicator that the area might have once been habitable.
The extended mission also creates exciting opportunities for Phoenix's onboard weather station.
The apparatus uses a skyward-pointing laser beam to profile the dust and clouds in the Martian atmosphere and to measure atmospheric pressure, temperature, and winds.
So far Phoenix has experienced the relatively benign weather of Mars's late spring and summer—but that is expected to change soon.
"For atmospheric science, the longer [the mission] lasts, the better, so we can begin to understand the seasonal changes," said Quebec-based Victoria Hipkin of the Canadian Space Agency.
"We're expecting to see much more in the way of dust and cloud activity as we go forward."
NASA also released a color, panoramic image of the Phoenix landing site, which had been created by painstakingly downloading and stitching together some 500 pictures.
The shot helps scientists better understand the features of the local, ice-dominated environment, which is covered by the planet's ubiquitous rust-colored dust.
Mark Lemmon, of Texas A&M University, said the lander's Surface Stereo Imager would keep blazing away as the mission continued—revealing seasonal changes on the Martian surface.
"Later in the year more frost will appear, and eventually [we'll see] a winter wonderland of carbon dioxide frost that will [signal] the end of the Phoenix mission in months to come."
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