The World Space Week is organized across the World from 4 to 10 October. In 1999, The United Nations General Assembly declared that World Space Week will take place from 4th October to 10th October every year, in commemoration and celebration of two key dates in the advancement of space technology and exploration.
World Space Week theme for 2017 is ‘Exploring New Worlds In Space’. The 4th October 1957 when Sputnik, the first human-made Earth satellite was launched, and October 10th when the Treaty on Principle Governing the Activities of States in the Exploration of Space and Peaceful Uses of Outer Space and other Celestial Bodies including the Moon, was signed.
Source- The Guardian