Now, scientists are running a series of tests to see how they can scrape up enough ice and move it to the oven before it vaporizes in the Martian atmosphere. The ice, which is a minus-135 degrees Fahrenheit and as hard as a sidewalk, has proven tough to scrape up, said Arvidson.

On Monday, the robotic arm tried 50 different scrapes and didn't dig up enough ice to test. Now, scientists are trying the rasp, which is on the back of the scoop. Arvidson said he's quite sure the rasp will be able to scrape up enough ice; the real challenge, he noted, is moving the scrapings into the oven before they disappear.

Because the water vapor in the atmosphere is so low and because the temperature is so cold, liquid water isn't stable on Mars, he explained. The ice, if not kept in shadow and quickly transferred to the analyzer, would simply vaporize.

Scientists are working on calculating how quickly they can scrape up some ice and move it, while making sure the Lander and robotic arm stay out of the sun.

Arvidson said it may be a week or more before the test can be run on the ice in TEGA.

Leslie Tamppari, a Phoenix project scientist at the Jet Propulsion Laboratory, said in the meantime that the Lander has been busy collecting atmospheric data and taking pictures of the rocks and soil around it.