NASA's rover Opportunity is celebrating its 15th year on Mars. However, Jet Propulsion Laboratory scientists say today's anniversary is bittersweet because they do not know the status of the rover. The golf-cart sized mobile landed on the Red Planet in 2004 and has traveled more than 28-miles, but its last contact with Earth was in June. Mars had a planet-wide dust storm that covered the rover's location, blocking so much sunlight that it could no longer charge its batteries.
Photo: NASA/JPL via Getty Images