WASHINGTON — After years of proposing, theorizing and deducing that there is water on Mars — at least in the form of ice — NASA scientists said they have finally confirmed it, after the Phoenix lander detected traces of water vapor wafting off a scoop of Martian dirt, researchers said Thursday.
"It's something we've been waiting quite a while for," said William Boynton of the University of Arizona. "We've now finally touched it and tasted it."
Earlier Mars expeditions had indicated that at least in the past, water existed on Mars — a key issue for scientists, since on Earth, liquid water is a key prerequisite for life. In the 1970s, photos seemed to show channels on the Red Planet's surface, a possible indication that water had flowed there before the atmosphere cooled.
In 2002, observations by an orbiting probe found evidence of vast amounts of water locked up in ice below the surface. Then, after the Phoenix Mars lander touched down May 25, researchers said it had provided solid evidence of water.
But researchers later concluded that it was ice that had evaporated.
Thursday, they said they had proof. The probe, which includes implements for scooping and gouging the Martian surface, cooked a dirt sample in a special oven, and scientists noted that a bit of the sample evaporated around the usual freezing point of water. "The fact that it melted at zero degrees Celsius leaves very little doubt that it is standard water ice," Boynton said. He said sensors also tested the chemical makeup of the vapor and found the familiar combination of two hydrogen atoms and one oxygen atom.
Also Thursday, NASA announced that the Phoenix mission, originally planned to end in late August, would be extended through the end of September. That extension will cost about $2-million, a NASA official said.