On this day, 42 years ago, on April 4, 1983 (February 21, 1983 in the lunar calendar), the first flight of the American Challenger was successful. The U.S. space shuttle Challenger made its first flight from April 4 to April 9, 1983. Orbiting the earth 80 times and reaching a range of 3.3 million kilometers, the entire launch and landing process went smoothly. During the orbital flight, the astronauts fully tested various systems of the space shuttle. They also deployed a large tracking and data relay satellite, conducted the first extravehicular space walk in nine years, and tested a new spacesuit. In addition, a series of space medicine and scientific experiments were conducted. Except that the huge communications satellite released by the Challenger failed to reach the predetermined synchronous orbit due to the satellite's own rocket, the entire flight was successful. Unfortunately, on January 28, 1986, during its 10th flight, the Challenger exploded more than 70 seconds after liftoff, causing the biggest tragedy in the world's aerospace history.