Since the 1950s, space technology has developed continuously, Artificial earth satellite According to the application field, it has developed into a series of communication, meteorology, navigation, resources and environment, military reconnaissance, scientific research, etc., and is developing towards high performance and high integration. With the comprehensive integration of satellite functions, the quality of satellites is also increasing, and the continuous improvement of the launch capability of rockets provides a technical basis for the development of large satellites. With the continuous development of satellite technology and application, people urgently need to speed up the development cycle of satellites while requiring to reduce the cost and risk of satellites. In particular, special satellites for single task and satellite networking need satellite technology with small investment and quick results. Therefore, small satellite technology came into being.
Satellites weighing less than 500 kg and costing hundreds of thousands to tens of millions of dollars are small satellites. It is divided into four grades: 500kg~100kg are small satellites; 100kg~10kg are microsatellites; 10kg~1kg are nanosatellites; Those less than 1 kg are chip satellites.
Compared with large satellites, small satellites are advanced, fast, cheap and reliable.
Small satellites are not simply small in quality, but the application of highly integrated technology and automation technology, especially the rapid development of computers, to realize the miniaturization of on-board control and processing computers. Small satellites can quickly realize the whole process from design, manufacturing, launch and in orbit operation, usually less than 12 months. A small satellite, including the launch price of about 30 million yuan, is not only cheap, but also low risk. Generally, the life span of small satellites is more than ten years.
Small satellites can be used for weather photography and ground detection The launch platform is flexible, not necessarily a fixed launch tower, but also can be launched from an aircraft.
Modern small satellites are widely used. In the civil field, it can be used in communication, earth observation, space remote sensing, meteorological observation, ocean exploration, scientific research and other fields. Among them, the use of small satellites for mobile communications has become a hot spot in today's development. "Iridium" and "Global Star" are typical examples. Small satellites also play an important role in military affairs, because they can quickly development It can be launched quickly and put into use in time, so it can meet the special requirements in wartime. 
Shenqi used companion star to shoot itself for the first time "Test Satellite 1" is the first transmission type stereo surveying and mapping small satellite in China, weighing 204 kg. It was jointly developed by Harbin Institute of Technology, China Academy of Space Technology, Chunguang Institute of Chinese President of Science and Xi'an Institute of Surveying and Mapping. It is mainly used for land and resources photogrammetry, geographical environment monitoring and mapping scientific experiments. This satellite has adopted a number of cutting-edge technologies of micro satellites, and has explored a new way for the development of China's micro satellite technology.
At 23:59 on April 18, 2004, the "Test Satellite 1" jointly developed by the Harbin Institute of Technology, the China Academy of Space Technology, the Chinese Academy of Sciences, and the Xi'an Institute of Surveying and Mapping, under the leadership of Harbin Institute of Technology, in conjunction with the Aerospace Science and Technology Group, was successfully launched from the "Long March" 2C carrier rocket at the Xichang launch base. The satellite operated normally and began its test mission in space.
The rocket ignited on time as scheduled and flew more than 10 minutes later, releasing "Test Satellite I"; After 30 seconds, release the "Naxing 1". from Xi'an Satellite Measurement and Control Center The measurement and control data from the satellite show that the two small scientific experimental satellites "Test Satellite 1" and "Naxing 1" have accurately entered their respective predetermined orbits, and the launch of one rocket and two satellites has been a complete success. Harbin Institute of Technology Aerospace Academy Han Jiecai, the president, is a native of Bazhong, Sichuan. After the launch, he firmly grasped the hand of our reporter and said, "I am very excited! I hope more Sichuan compatriots will join us!" "Naxing 1" is a nano satellite used for high-tech exploration and test, weighing less than 25kg, developed and used by Tsinghua University and Aerospace Tsinghua Satellite Technology Co., Ltd.
In September 2008, China's Shenzhou VII photographed the first time through a companion star (small satellite) in space spacecraft Exterior of 
