NASA's Mars Exploration Rover Mission (MER) is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars. It began in 2003 with the sending of the two rovers—MER-A Spirit and MER-B Opportunity—to explore the Martian surface and geology.

What does it take to get a spacecraft to Mars? This 60-second video covers a few key things to remember when planning a trip to the Red Planet.

Landing the Curiosity rover on Mars is the most difficult and nail-biting part of the whole mission. See just how hard it is to land on Mars in this 60-second video.