In 2008, the China Manned Space Engineering Office published a brief description of Tiangong-2 and Tiangong-3, indicating that several manned spaceships would be launched in the late 2010s to dock with Tiangong-3. The first Tiangong module, Tiangong-1, was launched in September 2011, and docked with the unmanned Shenzhou 8 spacecraft in November 2011, marking China's first orbital docking.
Tiangong-3 is a 'third generation' or modular space station project. Other examples of modular station projects include the Soviet/Russian Mir, the International Space Station (ISS) and the planned Russian OPSEK. The 'monolithic' first-generation space stations, such as the Soviet Salyut program and NASA's Skylab stations, were not designed for resupply, possessing only one docking port. Second-generation station projects, such as Tiangong-2, feature a second docking port, allowing for resupply and multiple crewed missions. Modular stations allow new modules to be added or removed from the existing structure over time, saving considerable costs and allowing greater flexibility.
Additional modules will dock to the axial port of Tiangong-3's core module. Using a mechanical arm, similar in function to the Lyappa arm on the Mir space station, modules will then be moved to the radial ports of the docking node.
Tiangong-3's design will form the basis of a larger, multi-module space station, which China plans to launch in the 2020-2022 timeframe. When complete, the station will have a total mass of approximately 60,000 kilograms (130,000 lb), and will support three astronauts for long-term habitation. The space station will have a design lifetime of up to ten years, and its components and service craft will be largely based on previous Tiangong modules. Its primary components will include:
A Core Cabin Module (CCM) – based on the Tiangong-3 design and analogous to the RussianMir Core Module, the 18.1-meter (59 ft) CCM will have a maximum diameter of 4.2 meters (14 ft) and a launch weight of up to 22 tonnes (49,000 lb). It will be launched first, to serve as a docking hub for future modules and resupply spacecraft.
Two Laboratory Cabin Modules (LCM-1 and LCM-2) – based on Tiangong-2, the two laboratory modules will each be 14.4 meters (47 ft) long, with the same maximum diameter and launch weight as the core module. They will be used to perform scientific research in microgravity.
A robotic resupply craft – based on the original Tiangong-1 module, the automated cargo spacecraft will have a diameter of 3.35 meters (11.0 ft) and a launch weight of around 13 tonnes (29,000 lb). It will be used to transport supplies and lab facilities to the space station.
A manned Shenzhou spacecraft will be used to transport crewmembers to and from the space station.
In 2011, Wang Wenbao, the director of the China Manned Space Engineering Office, asked the public to submit suggestions for names and symbols to adorn the space station and its cargo ship. He stated that "the crewed space program should have a more vivid symbol and that the future space station should carry a resounding and encouraging name", insisting that "the public should be involved in the names and symbols as this major project will enhance national prestige, and strengthen the national sense of cohesion and pride".
^ abcdeDavid, Leonard (2011-03-11). "China Details Ambitious Space Station Goals". SPACE.com. Retrieved 2011-03-09. "China is ready to carry out a multiphase construction program that leads to the large space station around 2020. As a prelude to building that facility, China is set to loft the Tiangong-1 module this year as a platform to help master key rendezvous and docking technologies."
^ abcdBranigan, Tania; Sample, Ian (2011-04-26). "China unveils rival to International Space Station". The Guardian (London). Retrieved 2011-04-27. "China often chooses poetic names for its space projects, such as Chang'e – after the moon goddess – for its lunar probes; its rocket series, however, is named Long March, in tribute to communist history. The space station project is currently referred to as Tiangong, or "heavenly palace"."