What do you think are the most significant events that have occurred in the past fifty years of robotic planetary exploration? Why?
I think that the greatest leap forward in scientific discovery and exploration by robots on another planet is the work done by the twin Mars Exploration Rovers (MER), Spirit and Opportunity. Their discoveries have revolutionized our view of the Red Planet by providing ground-scale details of mineralogy and geological processes.
Their greatest discovery to date was finding the first mineralogical evidence of many different water-related processes on Mars, which supported the physical indications of past rivers, lakes and oceans.
These two rovers together have taught us more about Mars than all the previous missions combined.
Though we lost Spirit in 2010, Opportunity is continuing to make scientific discoveries to this day.
Secondly, the most important first step forward in robotic planetary exploration is the Viking landers on Mars.
Viking 1 landed on Mars on 20 July 1976 and Viking 2 landed on Mars shortly thereafter on 3 September 1976.
Viking was the first truly robotic spacecraft sent from Earth to another planetary body -- a spacecraft that that was not directly controlled by humans. Viking was also the first autonomous landing on another surface. In this way, Viking set the precedent for -- and proved our capability of -- sending autonomous robotic spacecraft out into the solar system.
A close third is the Voyager mission, which continues to prove that we can send spacecraft far beyond our reach, and indeed out of our solar system.
Last Updated: 23 September 2013