Professor David John Southwood (born 30 June 1945) is a British space scientist and former President of the Royal Astronomical Society (2012-2014). Until 2011 he was Director of Science and Robotic Exploration at the European Space Agency. He also holds the post of Senior Research Investigator at Imperial College London. His research interests have been in solar–terrestrial physics and planetary science, including building the magnetic field instrument for the Cassini Saturn orbiter.