This month sees the start of one mission and the end of another. NASA’s OSIRIS-REx mission launched at the start of the month to go and study asteroid Bennu, and even bring back a sample to Earth.

Meanwhile, the end of the month sees the finale of ESA’s Rosetta mission, which has spent two years studying comet 67P/Churyumov-Gerasimenko. With stunning images accompanied by fascinating results from other instruments, not to mention the plucky little Philae lander, Rossetta has been one of the most exciting missions of recent years.

This month, the Open University’s Professor Monica Grady tells me about comets, asteroids, and these two exciting missions.

Originally broadcast on 26th September 2016 as part of Pythagoras’ Trousers on Radio Cardiff.