As folks here on Earth mark the passage of another year, two NASA robots a world away are creeping up on a big milestone of their own: seven years on the surface of Mars.
The golf-cart-size rover Spirit landed on Mars on Jan. 4, 2004. Its twin, Opportunity, hit the planet's red dirt three weeks later, on Jan. 25. The rovers were originally supposed to tool around the Martian surface for a mere 90 days, looking for evidence of the planet's past water activity, but both have far outlasted their warranties.
In 2009, however, Spirit got trapped in soft sand and in March 2010, the rover stopped communicating with Earth. Still, mission scientists think the intrepid rover may wake up in the next few months. Meanwhile, Opportunity is still going strong, making its slow, steady way toward a huge crater called Endeavour.