Sunset

NASA has released the winners of its contest to choose the best photos of Mars taken by its twin rovers, Spirit and Opportunity . The contest celebrates the third Earth-year anniversary of their landing. The voting began on January 3, three years after Spirit arrived on the Red Planet, and ended on January 24, the third anniversary of Opportunity's landing. NASA also announced winners of the best photos from Saturn contest.

The original mission was scheduled to last 90 Martian days, but that estimate has proved to be far short of the rovers' capabilities. A Martian day lasts 24 hours and 37 minutes of Earth time while a Martian year lasts 686.98 Earth days.

The photos in the gallery are presented according to their rank in the voting.

1. Spirit captured this sunset on Mars. The sun would appear to be about two-thirds the size as seen from Earth. Studying sunset and twilight images helped scientists better understand Mars' atmosphere.