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Mars Exploration Rover - Mission Events Timeline
Both Mars Exploration Rovers (MER) were launched from Cape Canaveral, Florida, during the summer of 2003. The first, Spirit, blasted off on June 10. The second, Opportunity, was launched on July 7. After leaving Earth, each spacecraft spent slightly more than six months in its "cruise phase" on the journey to Mars. During that trip, each spacecraft had a few minor mid-course corrections of its path along the way.
In January 2004 Spirit and Opportunity made it safely to Mars. Spirit landed in Gusev Crater on January 3, 2004. Opportunity touched down on Meridiani Planum on January 24, 2004.
Each spacecraft first had to enter the Martian atmosphere while traveling at a speed of 19,000 km per hour (12,000 mph)! Their heat shields kept them from burning up. When they had gotten within 10 km (6 miles) above the surface of Mars and had slowed to about 400 meters per second (1000 mph) their parachutes opened. Next, the landers inflated airbags around themselves to help cushion their landings. Retrorockets that fired just above the surface slowed the landers even more. Finally, the vehicles cut the lines connecting them to their parachutes and dropped 10 to 15 meters (33 to 48 feet) to the Martian surface. Each bounced more than twenty times before stopping.
After each lander was settled on the surface of Mars, it let the air out of its airbags and pulled the bags in to itself. Then each lander unfolded itself. Next, each rover spread out its solar panels and unfolded its wheels and camera mast. After engineers tested each rover's systems to make sure they were OK, each rover drove onto the surface of Mars. We think the rovers can last about 90 days on Mars. They are exploring during the daytime and "resting" at night. After a while the solar panels will stop making enough electricity to keep the rovers going. Hopefully we will learn a lot from them before that happens!