1. The first step into space for the exploration of outer space was taken on 4th October 1957 when the erstwhile Soviet Union (USSR) successfully launched the first man-made satellite “Sputnik-I” into space (Sputnik means fellow traveler). This first satellite weighed about 84 kilograms. Sputnik-I satellite had an orbit with an apogee of 941 kilometres and perigee of 227 kilometres. Sputnik-I was launched to carry out studies as a part of the International Geographical Year. The United States of America (USA) also followed the Soviet Union and launched their first spacecraft called “Explorer” after a few months which weighed only a few kilograms. Since then space technology has made very rapid progress. The satellites or other space-probes (called “payloads”) have grown many times in size and weight and their functions have become more and more complex and diverse.
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2. After a few weeks of the launching of Sputnik-I satellite, the erstwhile Soviet Union launched another satellite named Sputnik-II. The Sputnik-II satellite carried a dog named “Laika” into the outer space for the first time. The weight of this satellite was 500 kilograms. While the Laika dog was revolving around the earth in Sputnik-II satellite, its blood pressure, heart-beat and temperature were monitored for eight days continuously. After this the Laika dog was allowed to die in space because the technique to bring it back to earth safely had not been developed at that time. But the data collected by Sputnik-II satellite which took a dog into outer space, provided vital information which paved the way for sending the first man into outer space.
3. After the first un-manned space flight of Sputnik-I, it took nearly four years’ time to send the first man into space. The first man to go into space was Yuri Gagarin of the erstwhile Soviet Union (USSR). The name of space-craft which took Yuri Gagarin into space was Vostok-I which was launched on 12th April 1961. Yuri Gagarin completed a single revolution around the earth on 12th April 1961 in his space-craft Vbstok-I. After a few days of Yuri Gagarin’s flight, America also sent its first man into space. In this way, Alan Shepard became the first American to go into space on 5th May 1961.
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4. For many years erstwhile Soviet Union (USSR) and the United States of America (USA) were the only two countries of the world who had the know-how of space technology. Both these countries developed the space technology independently so as to use the satellites for various purposes. The areas in which artificial satellites have been used are : Long-distance communications; Survey of natural resources; Meteorological studies; Scientific experiments; Collection of information for military purposes (or Spying). Another aim of the space programme was to put man on the moon. Finally, an American space-craft called Apollo- 11 took man to the moon on 20th July 1969. Neil Armstrong was the first man to step on the surface of moon. Edwin Aldrin landed on the moon after another 8 minutes.
5. The significant achievements in the field of space science during the 1980s were the establishment of permanent “space stations” and the development of “space shuttles”. These space shuttles are used to take the astronauts into outer space and bring them back to earth a number of times. The other important achievements of the 19&0s are : Expansion in the areas of application of satellite technology ; establishment of a permanent observatory in space and the maiden flight of Voyager-II space-craft to all the planets of the solar system. The repair of a satellite in space by a team of American astronauts in April 1992 is a yet another achievement of space technology. This repaired satellite was then put back on its original orbit around the earth. The history of space exploration is extremely fascinating. Perhaps in no other area of science has the progress been so spectacular as in space technology.