Forty years ago, the two Voyager spacecraft were launched on their mission to fly past Jupiter and Saturn. A fortuitous alignment of the planets allowed them to take in Uranus and Neptune as well. And just a year earlier, the two Viking probes had landed on the surface of Mars, part of their mission to search for evidence of life. Monica Grady will discuss the achievements of Voyager and Viking, and how they changed forever our view of the Solar System. She will go on to look forward to new voyages to study the Moon, Mars and beyond - voyages which will highlight the international nature of space exploration.