The Chinese space industry has announced that the launch window for China’s second Space Laboratory module, Tiangong 2 (Tiangong = “Heavenly Palace”), has been set for 15—20 September. The launch vehicle and payload stack was rolled out from the vehicle processing building to launch pad on 9 September. Experience from previous human spaceflight missions suggests the fuelling of the launch vehicle normally begins 24 hours prior to launch, and will take 6—7 hours to complete.
The Tiangong 2 mission is the final part of Phase-II in China’s human spaceflight programme (Project 921). Phase-II is aimed for the development of advanced spaceflight technologies and techniques, including extra-vehicular activity (EVA) and rendezvous docking, to pave way for the construction of a permanently-manned multi-module space station in Low Earth Orbit (LEO) by 2022. This phase of the programme includes a EVA mission, and the launch of two Space Laboratories – temporarily man-tended orbital station modules that can be visited by expedition crews for a short period of time.
The first and only EVA mission was carried out in 2008, during the Shenzhou 7 mission. A three-man crew flew in orbit for 2 days and 20 hours, during which two Chinese astronauts conducted a 20-minute spacewalk to demonstrate the EVA capability, as well as to validate the design of the airlock and the indigenous EVA spacesuit.
The first Space Laboratory named Tiangong 1, also known as the Target Vehicle, was launched almost exactly five years ago, in September 2011. The module remained operational in orbit for two years, during which it was visited by three Shenzhou missions, including an unmanned mission Shenzhou 8 in November 2011, and two crewed missions Shenzhou 9 and 10 in June 2012 and June 2013 respectively. The module remains flying in orbit today but the mission control lost all communications with the module in March this year.
In February this year, the China Manned Space Agency (CMSA) announced that it was about to implement the final part of Phase-II, which includes the test launch of the new Chang Zheng-7 (CZ-7, or Long March 7) launch vehicle in June, the Tiangong 2 Space Laboratory in Q3, a manned expedition mission in Q4, and a cargo resupply demonstration mission in first half of 2017.
The CZ-7 launch vehicle test flight was successfully conducted from the newly-built Wenchang Space Launch Centre on 25 June this year, placing a number of payloads including a sub-scale experimental crew capsule into orbit.
The Tiangong 2 launch campaign began in July, when the Space Laboratory module was delivered to the Jiuquan Satellite Launch Centre for pre-launch testing and checkout. The CZ-2F / Tiangong 2 launch vehicle stack was rolled out to the launch pad on 9 September.
— China Space Report (@SinoDefence) September 9, 2016
Once the Tiangong 2 module is in orbit, it will fly in a 400 km near circular orbit autonomously for two months, during which the mission control will carry out various checks on the vehicle remotely. According to Chinese media, the Tiangong 2 module carries a total of 14 mission payloads including the world’s first-ever in-space cold atomic fountain clock, a Space-Earth quantum key distribution and laser communications experiment, a Gamma ray detector, a liquid bridge thermocapillary convection experiment, a pace material experiment, a space plant growth experiment, a multi-angle wide-spectral imager, a multi-spectral limb imaging spectrometer, and a stereoscopic microwave altimeter. In addition, the Space Laboratory module will also test a prototype robotic arm similar to that to be installed on the future space station, and release a Nano-satellite (Banxing 2) equipped with a 25 megapixel high-definition CCD camera.
In November, the Shenzhou 11 vehicle carrying a crew of two astronauts will be docked with Tiangong 2 for a 30-day expedition mission to demonstrate medium-term orbital living.
Once the manned mission completes, the Tiangong 2 module will resume its autonomous flight in orbit. A cargo vehicle Tianzhou 1 will be launched atop a CZ-7 launch vehicle from Wenchang around April 2017. The 13,000 kg mass cargo vehicle will dock with the Space Laboratory to demonstrate the resupply of both ‘dry’ and ‘wet’ cargoes in orbit.
The Tianzhou 1 resupply mission will also conclude the entire Phase-II of the human spaceflight programme, and the China Manned Space Programme will officially enter its Phase-III – the construction of a permanently manned space station. So far two flight missions have been confirmed: the programme will kick off in late 2017 with the test launch of the Chang Zheng-5B (CZ-5B, Long March 5B) heavy-load launch vehicle, which will be used to loft space station modules into orbit. Then in 2018, Tianhe 1, the first experimental core module of the space station, will be launched by the CZ-5B from Wenchang.
The Chinese space industry is currently on schedule to complete the construction of the permanently-manned space station by 2022. The station has a designed life of 10 years and will remain operational in orbit until the early 2030s. This will also conclude China’s 30-year plan to develop human spaceflight technology and build a space station, which was first drafted in the early 1990s. China is currently studying the feasibility of a manned lunar landing mission in the late 2030s, and the possibly the construction of a lunar base thereafter.