In particular embodiments, a system may include a spacecraft and optical ground terminals. The spacecraft includes at least an optical space terminal and a space switch unit. The space switch unit is configured to receive physical layer data frames from one optical space terminal, regenerate data-link layer data packets based on the physical layer data frames and route the regenerated data-link layer data packets to another optical space terminal. The optical ground terminals are configured to receive data-link layer data packets by one of the optical ground terminals, encode the received data-link layer data packets into physical layer data frames, transmit encoded physical layer data frames from one of the optical ground terminals to a respective optical space terminal through multiple forward channels at a data rate of 1 Tbps or above, the encoded physical layer data frames are decoded by the respective optical space terminal.