Chinese astronauts who manually docked their spacecraft with an orbital laboratory on June 24 have proven a technology crucial for the nation’s proposed space station program.

Astronaut Liu Wang, helped by his two colleagues on board Shenzhou 9, took 7 min. to bring the spacecraft into contact with the laboratory, Tiangong 1, from a range of 400 meters (1,300 ft.). That was 3 min. faster than the performance of the automatic system that Shenzhou 9 had used on June 18 and Shenzhou 8 had used last year in China’s first space docking exercise.

Redundancy, not speed, is the real issue, however. “The automated docking and manual docking are both essential and they serve as a backup for each other,” Zhou Jianping, chief designer of China’s manned space program, told the Xinhua news agency. The space station is to be built around 2020.

Until the Shenzhou 9 mission, Chinese astronauts had not controlled their spacecraft, which instead were maneuvered by commands from the ground. “The manual docking was beautifully conducted,” says Liu Weibo, the program manager responsible for the astronaut system. “It was very accurate and swift.”

Four missions supporting the development of rendezvous and docking technology and techniques — Shenzhous 7, 8, 9 and 10 — have been budgeted at about 19 billion yuan ($3 billion), says the spokeswoman for the manned space program.

Shenzhou 10 is due to be launched next year. It was provisionally scheduled as a backup. Had Shenzhou 8 failed to prove automatic docking last year, then Shenzhou 9 would have been launched with the same task, and Shenzhou 10 would have attempted the first manual docking.

The next mission could well include manual docking anyway. Although astronauts have shown that they and their manually operated systems can do the task, China will presumably not be satisfied with just one practice run.

According to Liu Weibo, the procedure worked because Liu Wang was up to the task psychologically and in terms of training, the crew cooperated and the equipment was reliable.

The mission, which also has included the first transfers of people and goods from one Chinese spacecraft to another, will end with the return capsule’s descent to Earth on June 29, a day after separation from Tiangong 1.