After a thorough check-out of Tiangong-1's environmental, power, and communications systems, the three-person crew of the Shenzhou-9 spacecraft entered the small prototype space lab module, to begin a 10-day stay on board. The docking was performed through computer control from the ground, as it had been with the unmanned Shenzhou-8 craft last November. Later in the mission, the two craft will undock, and then re-dock under the manual control of the crew.
Automatic docking is more difficult and created one of the worst potential disasters in space history, when an unmanned Russian Progress cargo ship tested a new automatic docking systen with the Russian Mir space station in the late 1990s. The Progress crashed in to a station module, causing it to depressurize. Quick thinking and action by the crew saved the rest of the Mir station. The Chinese crew will carry out the manual docking as a test, in case, in the future, there is a problem with the automatic system.
All three crew members will live in the Tiangong-1 while the craft are docked, and Shenzhou-9 will be basically shut down. While two sleep, one astronaut will remain on duty. Tiangong-1 has about double the volume of the Shenzhou, and, as seen in the live TV coverage of the mission, has adequate space for experiments, as well as living quarters.