Abstract: To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle, this paper proposes the implementation scheme of a space-based TT&C terminal, analyzes and solves the miniaturized design of equipment and the key technology for high-efficiency heat dissipation. The phased array antenna test shows that without external heat dissipation measures, the phased array antenna can work for a long time to meet the working requirements of launch vehicle, which has been verified in the LM-8 mission, and has wide engineering application prospects.