The development of reliable, high-powered boosters has enabled researchers to send probes to distant planets. Without these workhorses our science would remain tied to the Earth. This episode examines a range of launchers integral to space research.

Early in the life of the solar system Mars appears to have had Earth-like conditions. Planetary researchers have been targeting Mars to gain insight into how our own planet developed. We look at probes orbiting Mars and rovers exploring its surface.

The ringed planet is of immense interest to researchers who believe that Saturn's ring system will share similarities with the proto-planetary disc from which the solar system evolved. The Cassini probe spent 13 years examining the Saturnian system.