44 years ago today, on September 20, 1981 (August 23, 1981 lunar calendar), our country launched three satellites for the first time with a carrier rocket. China successfully launched three satellites with one arrow for the first time. On September 20, 1981, China successfully launched a group of three satellites with one rocket for the first time, thus becoming the fourth country in the world to master this "one arrow multiple satellites" technology. There are two common ways to launch multiple satellites with one arrow: the first is to send several satellites into the same orbit at a time; the second is to release satellites in batches, so that each satellite can enter different orbits. The three satellites launched by our country with one rocket used the above two methods. At 5:28:40 am on September 20, 1981, our country's launch vehicle carried the three satellites and took off from the launch pad. 7 minutes and 20 seconds after takeoff, "Practice" 2A and "Practice" 2B separated from the launch vehicle; 3 seconds later, "Practice" 2 separated from the rocket. After the three satellites left the launch vehicle, they entered the predetermined earth orbit and began to carry out various exploration missions in space. For decades, various types of man-made satellites and manned spacecraft in our country have been widely used in economic construction, scientific and technological development, national defense construction and social progress, and have played an important role in enhancing the country's economic strength, scientific and technological strength, national defense strength and national cohesion. Looking back at the history of the launch of man-made satellites in our country: On April 24, 1970, China's first man-made earth satellite - Dongfanghong-1 was successfully launched from Jiuquan Satellite Launch Center, which opened the prelude to China's space activities. In March 1971, China successfully launched the Shijian-1 science and technology test satellite. After the initial success of the launch of the first man-made satellite, China has overcome technical difficulties such as orbit change, re-entry, heat prevention and recovery. It successfully launched and recovered the first returnable remote sensing satellite on November 26, 1975, becoming the third country in the world to master satellite return technology after the United States and the former Soviet Union. On April 8, 1984, China's first geostationary orbit communications satellite, Dongfanghong-2, was successfully launched, becoming the fifth country in the world to independently develop and launch geostationary orbit satellites, opening up a new era in China's satellite communication industry. In September 1988, China successfully launched the Fengyun-1 sun-synchronous orbit meteorological test satellite, becoming the third country in the world to develop and launch polar-orbit meteorological satellites. In September 1990 and May 1999, China successfully launched Fengyun-1 and the improved Fengyun-1 meteorological application satellite again. In June 1997, the Fengyun-2 geostationary orbit meteorological satellite was successfully positioned over the equator at 105 degrees east longitude, making China the fifth country in the world to develop and launch geostationary meteorological satellites on its own. In October 1999, the first digitally transmitted earth remote sensing satellite jointly developed by China and Brazil, the Resource-1 01 satellite, was successfully launched. In October 2003, the Resource-1 02 satellite was successfully launched. In September 2000, China's self-developed China Resources-2 01 satellite was successfully launched, and then successfully launched 02 and 03 satellites respectively. Its resolution is higher than that of the Resources-1 series of satellites, and a three-star network has been formed, indicating that our country's satellite development technology implementation has made a historic leap. At the same time as the successful launch of the Resources series of satellites, in May 2002, China successfully launched the first ocean color and water temperature monitoring satellite - Ocean-1 satellite; in April 2006, China successfully launched China's first microwave remote sensing satellite - Remote Sensing Satellite-1. In October and December 2000, two Beidou-1 navigation satellites were successively positioned over the equator at 140 degrees east longitude and 80 degrees east longitude. On May 25, 2003, the third satellite of the Beidou-1 navigation system was successfully launched, enabling China to initially form the first regional satellite navigation system. This achievement shows that China has become the third country in the world after the United States and the Soviet Union to develop and launch its own navigation satellites.