VOA常速英语:Ten Years of Roving Around Mars

WASHINGTON — The U.S. space agency, NASA, is celebrating the 10th anniversary of its Mars Exploration Rover Mission (MER), which began with the arrival of its robotic vehicles Spirit and Opportunity on the red planet in 2004. The anniversary event, held at the National Air and Space Museum, in Washington, featured a panel of NASA scientists discussing the achievements of the vehicles that have landed on Mars so far, and the future plans for exploring the planet.

A golf-cart sized vehicle named Spirit landed on Mars on January 4, 2004, while its twin, Opportunity, touched down three weeks later on the opposite side of the planet.

Although designed to operate for only 90 Martian days (Martian days are about 40 minutes longer than days on Earth), both rovers functioned much longer, and provided mission scientists huge amounts of information about Mars. Geologist John Grant, who was involved with the mission, said the rovers greatly enhanced scientists’ understanding of the planet’s geologic history.

“What we essentially get is a field geologist on Mars. Something that can move around on the surface, interrogate the rocks, tell us something about the geologic setting, the environments that were there in the past, but more specifically - what the role of water was in shaping those environments,” said Grant.

NASA lost communication with Spirit in March 2010, but Opportunity remains active, sending scientific data after traveling more than 38 kilometers around the Martian surface. The most significant discovery was evidence that Mars once had water, said Steve Squyres, the mission's principal investigator.

“I did not expect that the evidence for liquid water at and below the surface of Mars was going to be that compelling, that much in our face, you know, when we first landed,” recalled Squyres.

David Lavery of NASA's Mars Exploration Program said the technologies developed for the Mars rovers are now making their way into everyday life here on Earth.

“I think we’ve all heard at this point about the Google autonomous cars that are now traversing the highways. The technology that is used onboard there, in fact some of the people who developed that technology, have common roots back in technologies that were actually flown on the Mars rovers,” said Lavery.

In August 2012, NASA landed the rover Curiosity on Mars. The size of a small car, it is powered not by batteries but a small nuclear reactor, which should allow it to operate for years. Curiosity will be joined by another rover in 2020, as the U.S. space agency looks ahead to an eventual visit by humans.