Exploration of Mars
The Viking program launched "Viking 1" and "Viking 2" spacecraft to Mars in 1975; The program consisted of two orbiters and two landers – these were the first two spacecraft to successfully land and operate on Mars.
The primary scientific objectives of the lander mission were to search for biosignatures and observe meteorologic, seismic and magnetic properties of Mars. The results of the biological experiments on board the Viking landers remain inconclusive, with a reanalysis of the Viking data published in 2012 suggesting signs of microbial life on Mars.
The Viking orbiters revealed that large floods of water carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers. Areas of branched streams, in the southern hemisphere, suggest that rain once fell.
Timeline of Mars Science Laboratory
"Curiosity" landed in the Gale Crater at 05:17 UTC on August 6, 2012. Upon reaching Mars, an automated precision landing sequence took over the entire landing events. A cable cutter separated the cruise stage from the aeroshell and then the cruise stage was diverted into a trajectory for burn-up in the atmosphere. Landing was confirmed simultaneously by 3 monitoring Mars orbiters. "Curiosity" landed on target and only from its center. The coordinates of the landing site (named "Bradbury Landing") are: .