68 years ago today, on December 6, 1957 (October 15, 1957 in the lunar calendar), the United States experimental satellite exploded. On December 6, 1957, the Pioneer rocket carrying the United States 'first experimental artificial satellite rose to a few feet above the ground after launch and fell back to the ground and exploded and burned. The U.S. authorities originally decided to launch the experimental satellite, which actually weighed only 1.5 kilograms, on November 4, but repeatedly postponed the launch until 16:45 GMT on the 6th (more than two months after the Soviet Union launched the first artificial satellite). The U.S. Department of Defense announced that two seconds after the rocket was launched, the first-stage rocket lost its thrust. The rocket somersaulted and fell back to the launch pad head east, exploding. People hiding in heavily thick-walled protective chambers saw the rocket surrounded by burning flames behind a plume of smoke. The first and second stages of the rocket have all been burned down, and the third stage of the rocket containing the artificial satellite fell down without being burned out. The launch pad was severely damaged. Fortunately, no casualties were caused. Smith, who announced the launch failure on behalf of the Vanguard rocket launch headquarters, said that normally it takes six weeks around the clock to prepare for a three-stage rocket launch. A spokesman for the Department of Defense in Washington said it would take about 30 days to conduct the next test. Dr. Hagen, head of the U.S. satellite launch program, held a press conference more than two hours after the accident. He announced the news with a gloomy face. He said: "We have conducted a detailed study of all the records at hand, but so far, no one can know with certainty what caused this failure. For completeness reasons, it is not yet possible to conduct a careful inspection of the three-stage rocket itself." Dr. Hagen also complained to reporters that he personally believed the United States should not have disclosed too much about the launch in advance, but others dismissed him. He said that due to too much disclosure, the public had been lost and could not see that the launch was just a test. The failure of the United States to launch a satellite triggered a downward trend in New York stocks, which is estimated to have caused the prices of various stocks on the New York Stock Exchange to drop by more than 1.2 billion yuan.