Apart from the Earth, Mars is the most explored planet in our Solar System. Since the 1960′s, dozens of spacecraft have been sent to orbit and, in some cases, land on our planetary neighbour.
Artist's concept of a rover working on Mars. (credit: NASA)
Mars does not seem an interesting place at first glance: the low temperature and pressure have given the planet a very hostile environment. However, some pictures, taken by spacecraft orbiting Mars and telescopes on Earth, suggest that the early Mars was wetter and more “hospitable” than it is today. So, did Mars once have water flowing on its surface; and if so, how long ago?
To answer these questions, NASA sent two robotic rovers to the red planet– named Spirit and Opportunity – to study two different areas of the Martian surface and look for any evidence that there was once liquid water on Mars.
Getting to Mars
Spirit and Opportunity were launched separately in June 2003 and arrived at the red planet in January 2004. Nevertheless, this long trip was not the worst part: the biggest preoccupation of the mission scientists was landing the robots on Mars safely. In the video below you can see ...