Key technology of Chinese space VLBI

Abstract

Chinese Space VLBI was selected as a background research project to further refine scientific objectives and overcome key technologies in 2012. After three years of research, we condensed out the main scientific objectives of Chinese space VLBI, i.e., directly imaging of the super massive black hole, accurate measurement of the mass of the central black hole, research on the mystery of the great energy of active galactic nuclei, the formation of the jet, the acceleration and collimation mechanism, etc. Important progress has been made in the research of key technologies. The attitude control method with high precision of 45 (3 sigma) is proposed. A high precision onboard deployable antenna with 10 m diameter for Q-band VLBI observation is developed. An onboard cryogenic receiver prototype with K-band noise temperature of 30 K and Q-band of 60 K, and an onboard astronomical data processor prototype with the maximum bandwidth of 512 MHz are developed. Two methods of high accuracy frequency reference are confirmed. The active type of onboard H-Maser which can satisfy the Q-band observation with the interference loss less than 0.01 is determined. A close-loop reference signal transmission experiment system based on the ground H-Maser signal is developed. Research progress and key technologies of concise scientific objectives has laid a good foundation for the space VLBI Project.