The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
Go to topicBorn in the Netherlands, Dirk Brouwer received his Ph.D. in 1927 at the University of Leiden and then joined the faculty at Yale University, where he worked in celestial mechanics with Ernest W. Brown. While still a student he determined the mass of Titan from its influence on other Saturnian moons. From 1941 to 1966 he served as director of the Yale University Observatory and editor of the Astronomical Journal. Brouwer developed general methods for finding orbits and computing errors and applied these methods to comets, asteroids, and planets. He was one of the first to use electronic computers for astronomical computations. He computed the orbits of the first artificial satellites and from them obtained increased knowledge of the figure of the earth. His book, 'Methods of Celestial Mechanics', taught a generation of celestial mechanicians. He also redetermined astronomical constants.