Heated to 32 degrees Fahrenheit, a sample of soil being analyzed by NASA’s Phoenix Mars lander let out a puff of vapor, providing final confirmation that the lander is sitting over a large chunk of ice.

“We’ve now finally touched it and tasted it,” William V. Boynton, a professor at the Lunar and Planetary Laboratory at the University of Arizona and the lead scientist for the instrument that detected the water, said at a news conference on Thursday. “And I’d like to say, from my standpoint, it tastes very fine.”

The main goal of the lander is to analyze ice in the northern arctic plains. Since it arrived on the planet on May 25, scientists have visually seen what they were almost certain was ice: a flat, shiny patch beneath the lander and tiny white chunks in a trench dug by the lander’s robotic arm.

But the analysis performed in one of the instruments, heating the sample in a tiny oven and then observing what vaporized, was the first direct measurement.