Four hundred years ago Sir Isac Newton showed that the physical principles governing the dynamics of both the terrestrial and celestial objects are the same. The famous "laws of motion", laid down by him successfully described the orbit of planets, moon and the comets. This is the beginning of the modern scientific age. The scientific achievements of mankind have been steadily progressing since than, and what were fantasies earlier are made into reality. As a result of the application of the same physical principles, man placed his foot on the brightest object of the night sky - the moon. It indeed was a "giant step for the mankind" as Niels Armstrong declared. The object, which had been worshiped by various religions over centuries, was conclusively shown to be similar to our earth, when they brought the lunar material on their return. This made us both proud and humble, for we came to know, we can do things as great as stepping into moon and the earth we live in is really a tiny object in the vast universe. This is the single great achievement of space science and technology of 20^th century.
 

The space age started with the launch of first Russian satellite Sputnik 1 on 4 October 1957. Ever since, the rocket powered launch vehicles carried state of the art scientific equipment to explore moon, the sun, solar system and the cosmos. This resulted in designing and fabricating the instruments having more than 6000000 components with reliability greater than 99.9999%. In 1960s man landed on moon and in 1970s the planetary exploration continued the space march. The comet Halley, which orbits the sun in about 76 years was photographed from a distance of about 500 kms in the year 1986. The success of launch and recovery of Space Shuttle made the space just another location in 1980s. This opened a variety of new vistas of science and technology. As the cold war ended, one expected that 1990s will witness a spectacular advancement in scientific research, specially in space front. This decade, however, did not have such major breakthrough. Even the "International Space Station" program became slower than expected. Is it the cold war competition responsible for rapid developments of space technology in 1970s? As some say, President Kennedy was desperate to show the American Supremacy, resulting the moon lander project.

In any case, we have come a long way in this endeavor. Space became an enterprising commodity from both commercial and military point of view. Today some people have started selling the lunar land like real estate! It was expected. Consequently, in 1958, shortly after launching of the first artificial satellite the General assembly of the United Nations established an ad hoc committee of peaceful uses of outer space in order to deal with both international cooperation and deal with legal problems. The committee currently comprises of 61 member states, whose present chairman is Professor U. R. Rao. Incidentally, Professor Rao is the chairman of the governing council of Physical research Laboratory, to which Udaipur Solar Observatory belongs. This United Nation body created an outer space treaty in 1966. The treaty has 17 articles, signed in January 27, 1967 and entered into force on 1^st October 1967. Hence we celebrate this week as International Space Week. Let us discuss some of its important articles. The Article I of the treaty declares that space shall be free for exploration and use by all states. Article II states that outer space, the moon and the other celestial bodies are not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means. Article III provides that a nation?s activity in exploration and use of outer space shall be in accordance with the international law, in the interest of maintaining international peace and security.