China's three astronauts sent best regards to students back on the Earth at the end of the country's first "space class".

"I wish all you students will study hard and gain knowledge and add luster to the Chinese dream," says Nie Haisheng.

"The outer space is deep and has numerous mysteries. The exploration is limitless and let us make joint efforts in this regard," says Zhang Xiaoguang.

"The space dream never loses its gravity and the science dream knows no bounds," says Wang Yaping.