Fifty-four years ago today, on August 7, 1971 (June 17, 1971 lunar calendar), Apollo-15 landed safely. On August 7, 1971, the American spacecraft Apollo-15 and three astronauts landed on the moon and splashed down safely in the Pacific Ocean. The astronauts then participated in a simple welcome ceremony aboard the aircraft carrier, where the entire crew prayed to God and thanked God for their safe return. The three Apollo-15 astronauts were David R. Scott, James B. Irving, and Alfred M. Worden. They used the lunar rover for the first moon landing flight on July 26, 1971. The moon landing site was in the Hadley-Apennine region near the Apennine Mountains. They carried out three lunar surface activities, a total of 18 hours and 37 minutes. On the way back to Earth, Worden carried out extravehicular activities for 38 minutes. The entire flight lasted 12 days, 7 hours and 20 minutes. The lunar surface stay time was 66 hours and 45 minutes. The lunar rover traveled a total of 27.9 kilometers. The "Apollo-15" moon landing flight had several features: First, the structure of the spacecraft was modified, such as the use of double hatch cover, strengthening the hatch lock, improving the performance of pressure and safety control system, so that in the case of cockpit perforation, astronauts will have more time to put on space suits than before to save their lives. At the same time, the spacesuit has also been improved, which enhances the flexibility of astronauts, and extends the stay time of astronauts on the lunar surface, doubling the number of scientific experiments. In addition, in addition to the first use of the lunar rover, it is also the first time to launch a small satellite in lunar orbit; for the first time to carry orbital sensors in the service module, and set up a lunar surface experiment kit; for the first time, isolation measures have been cancelled - because after the first 3 inspections, there is no "lunar plague" at all. Humboldt crater seen from Apollo 15