2065438+On April 27th, 2007, Tianzhou-1 and Tiangong-2 completed the first in-orbit propellant replenishment test. In September, Tianzhou-1 successfully completed the five-month "Space Express" mission. The successful completion of the Tianzhou-1 mission marks the successful completion of the second step of China's manned spaceflight project, and also declares that China Aerospace has steadily entered the "space station era".