VOA常速英语:Curiosity Treks Into Second Year on Mars

It has been 12 months since the Curiosity rover landed on Mars.

NASA says, in that time, the rover has driven across more than 1.6 kilometers of Martian terrain. It has found evidence of an ancient stream bed and signs of wet conditions from multiple periods.

Curiosity was the first rover to bore into Martian rock and reveal that the interior of the Red Planet is actually gray.

Core Objective Accomplished

NASA scientists say Curiosity has already answered the mission's core question: was ancient Mars capable of supporting simple forms of life, such as micro-organisms?

"Mars was habitable in its past," said Jim Green, director of the planetary division at NASA's Science Mission Directorate.

"We found all the ingredients of life as measured in this material that's deposited in this ancient riverbed," he said, referring to Curiosity's findings of hydrogen, oxygen and other elements.

Geologist and Photographer

Curiosity has 10 scientific instruments, amounting to a roving laboratory.

The space agency says the rover has fired more than 75,000 laser shots to vaporize rocks and soil and study their composition. It also has provided more than 70,000 images to give us a new view of Earth's neighbor.

Curiosity is not a life-detection mission, but its findings provide the groundwork for the next Mars rover, to be launched in 2020, says NASA's Green.

"Knowing that Mars was an environment that was habitable in its past, we're going to start seeking the signs of potential life that could have existed on Mars," said Green. "And that, if we could answer that question, will change everything.

Why Mars?

NASA Administrator Charles Bolden says Mars is the most Earth-like of the planets in our solar system.

"If life exists beyond Earth, and I am one who believes that it may very well, Mars, for me, is the most likely place that that life will be found," he said at an event to commemorate Curiosity's first anniversary on the Red Planet.

As NASA plans future Mars missions, Curiosity is traveling in the deep,150-kilometer-wide depression called Gale Crater. It is heading toward Mount Sharp, where it will study the lower layers of that Martian peak and search for clues about the planet's evolution.