Washington - After days of problems attempting to sample the Martian soil, NASA's Phoenix lander has filled one of its "ovens" with dirt and will now bake and analyze its contents, scientists said Wednesday.

"We have an oven full," University of Arizona scientist Bill Boynton said. "It took 10 seconds to fill the oven. The ground moved."

The advance comes after several days of frustration when the lander's robot arm on Friday collected dirt but its particles proved too large to filter into the tiny ovens designed to sample its contents.

The 420-million-dollar Phoenix mission is sampling the soil in a hunt for evidence of ice or water that could have once supported life on Mars.

Phoenix shook the dirt to get it through a filter designed to keep large chunks of soil from clogging the oven, but the move at first appeared not to have worked.

Scientists were surprised that a final attempt got the dirt into the oven, and Boynton said the cumulative effect of all the shaking may have helped or that the dirt itself may have changed slightly after sitting on the screen for several days.

They hope analysis will tell why the soil proved so clumpy.

The craft landed last month after a 10-month, 680-million- kilometre journey. The first evidence of water on Mars was found by the Odyssey orbiter in 2002, and NASA wanted to send a rover to the northern area of the planet, where it believes there are heavier concentrations of ice ground. (dpa)