This is a tool that can help people use ground-based telescopes to find new planets. The secret lies in observing the gravitational interaction between planets and their stars. "laser pointer comb" is not actually a brand-new method. The so-called "new" here actually means that the current accuracy is far beyond that. With the help of lasers and their derived atomic clocks, astronomers can accurately obtain data about distances.
With the maturity of light scattering technology, "laser comb" has gradually become the main tool for accurately measuring the Doppler effect. It scatters light and uses a large mass spectrometer for analysis. Under the premise that ground-based telescopes are becoming more and more advanced, people have been able to use them to find new planets similar to Neptune. At present, due to the limitation of the carrier frequency of the microwave communication commonly used on satellites, the communication rate has approached the limit in application, and the microwave communication has gradually become "remaining and insufficient".
Space laser communication uses laser as the carrier. The frequency of the laser is very high, 3-4 orders of magnitude higher than the frequency of microwave. It has a very huge communication capacity and can easily achieve a communication rate of more than 10Gbps. It can obtain Tbps by means of multiplexing. The above communication rate can easily realize the real-time transmission of massive data. In addition, space laser communication also has the advantages of strong anti-interference ability, strong anti-interception ability, good security and confidentiality, small size, light weight and low power consumption, and the quality of communication is higher.
With the establishment of earth-moon laser communication link, the communication rate can reach 622Mbps. How to realize space laser communication. To put it simply, space laser communication is to load information electrical signals on the laser through modulation. The two ends of the communication are initially positioned and adjusted, and then the beam is captured, aimed, and tracked to establish a dynamic optical communication link, and then the light passes through. Vacuum or atmospheric channels transmit information.
The space laser communication system is extremely complicated. It includes light source system, transmitting and receiving system, beacon system, acquisition, aiming, tracking (APT) system and other auxiliary systems. Among them, the acquisition, aiming, and tracking (APT) subsystem is a unique system of the space laser communication system. The APT sub-system is mainly responsible for the establishment and maintenance of the space green laser pointer communication link. Because the beam divergence angle of the space laser communication terminal is very small, which is a micro-arc measurement level, this puts very high requirements on the APT system, and the tracking accuracy reaches about 1μrad. . This accuracy is hailed by Japanese scholars as observing the tip of a moving embroidery needle on Mount Fuji in Tokyo, Japan.
What counts as space laser communication. There are six types of space laser communication links: inter-satellite laser communication, satellite-to-ground laser communication, star-to-air laser communication, space-to-air laser communication, space-to-ground laser communication, and ground-to-ground laser communication. The channel of the inter-satellite laser communication link is a free-space channel, and there is no interference from atmospheric and meteorological factors. It is the most suitable application for laser communication. Therefore, all countries choose the inter-satellite laser communication link as the entry point for laser communication in space applications. .