The first robot sent to Mars was an orbiter called Mariner 4, which flew past Mars on July 14th 1965 and took the first close up photographs of another planet.
The first robots to actually land on Mars were the Viking landers. Viking 1 landed July 20th 1976, followed by Viking 2 on September 3rd 1976. Both landers were accompanied by orbiters that took photos and scientific data from above the planet.
There are robots currently working on Mars. These include Spirit and Opportunity that are roving away on the Martian surface, Mars Express and Auroaβs Trace Gas Orbiter are orbiting the planet. Mars Express even has the first webcam of another planet available!
Work on building the first European Mars Rover has been underway for 4 years and will continue right up until launch in 2018.
You can hear Deep Space High: Destination Mars on Fun Kids Radio or listen to the series below!