Eastbourne, East Sussex BN20 9HT
The Rosetta mission to Comet 67P/Churyumov–Gerasimenko
Dr Simon Green (Senior Lecturer in Planetary and Space Science, The Open University)
Comets are the left-over components of the planet-building process in the outer reaches of the Solar System, deep-frozen since their formation over 4.5 billion years ago. The comets we see today in the inner Solar System, with their characteristic comae (heads) and vast tails, are in the very final stages of their lives, as the Sun’s heat vaporizes the ices, dragging away dust grains and eroding their surfaces. Since the 1980s, a number of highly successful comet missions have given us close-up views of cometary nuclei and the opportunity to sample directly their tenuous atmospheres. However, these missions provided only brief snapshots during their high-speed flybys. As well as performing the first ever landing on a cometary surface, Rosetta has provided us with the first opportunity to study a comet in minute detail, observing the build-up of activity as it approaches the Sun, and giving us new insights into how comets work. Dr Simon Green will summarise the key results from the Rosetta mission, with particular emphasis on the four instruments on the orbiter and lander with Open University involvement, and explain how they have changed our understanding of the structure, composition and constantly changing properties of comets.
Simon Green is a Senior Lecturer in Planetary and Space Sciences at The Open University. His research focuses on physical studies of planetary surfaces and small Solar System bodies (asteroids, comets, interplanetary dust and space debris) through analysis of spacecraft data, ground and space-based observations and modelling. He graduated from the University of St. Andrews in 1981 with a BSc in Astronomy and completed his PhD at the University of Leicester in 1985. His PhD project included a search for fast-moving objects using the Infrared Astronomical Satellite (IRAS), which led to the discovery of three asteroids (including 3200 Phaethon, the parent body of the Geminid meteor shower), six comets (including C/1983 H1 IRAS-Araki-Alcock) and the first cometary dust trail, associated with comet 10P/Tempel-2. He has subsequently worked on numerous Solar System space missions including Giotto, Cassini and Huygens, Stardust and Rosetta. His current research projects include analysis of cometary dust properties from Rosetta and other missions, observations of near-Earth asteroids to investigate their thermal and physical properties, preparatory studies for a planned ESA mission to return samples from the surface of Phobos and the study of missions to deflect asteroids from potential Earth impact. Simon has taught astronomy for over 30 years and has co-written four astronomy and planetary science textbooks. He has given over 150 public talks, and radio and TV interviews, including a talk to the EAS on ‘Catastrophic Impacts in the Solar System’, way back in June 1999. Asteroid (9831) Simongreen was named in 2004 “in recognition of his work in the observation of asteroids and transneptunian objects over 20 years, starting with the IRAS satellite to detect fast moving objects.”