In 1950s, China's independent nuclear program began with the help of more than 1,500 professional returnees. On October 16, 1964, China exploded its first atomic bomb. On June 17, 1967, China successfully tested its first hydrogen bomb. On April 24, 1970, China's first satellite Dongfanghong 1 was launched into the space. China thus became only the fifth country in the world, after the the Soviet Union, U.S., France and Japan, to independently develop and launch a satellite into space. Those successes greatly strengthened China's position on the international stage and guaranteed peace for the country and the world at large. It is a demonstration of the nation's power and determination.