Second Chinese space lab will be delivered to space on atop of Long March 2F/G rocket between 15 and 20 September to Low Earth Orbit with altitude of around 393 km.
Announced by official sources, launch will be important moment in Chinese space program. Tiangong-2, successor of Tiangong-1, will be delivered to orbit on atop of Long March 2F/G rocket launched from Jiuquan Satellite Launch Center. Tiangong-2 covered with payload fairing on atop was rolled out from the assembly facility to launch pad on Friday, 9 September, 2016 at around 02:30 GMT. It was delivered on special rail platform in vertical position to launch pad placed around 1.5 km from integration facility.
Tiangong-2 is very similar to Tiangong-1 due the fact that it is based on backup Tiangong-1. It is long for 10.2 m with diameter of 3.35 m and weighs 8.5 t Service module with solar arrays (with span of 17 m after deploying) is slightly narrower with diameter at 2.8 m and length of 3.3 m. It offers 15 cubic meters for 2 or 3 crew members (for maximum 30 days mission). One of the main differences between first and second Tiangong is opportunity to utilize robotic cargo vehicle, Tianzhou. Docking will be possible thanks to APAS (Androgynous Peripheral Attach System) docking port installed in the front of the habitable module. With 1.4 m of diameter and bases on two identical mechanisms installed on any docking vehicle and in Tiangong-2. Tianzhou will be launched with first resupply mission in the history of Chinese space program in 2017. Important change comparing to Tiangong-1 is also CSSM (Chinese Space Station Manipulator system) – robotic arm designed by China Academy of Space Technology (CAST). With reach up to 10.5 m and able to bear the weight up to 25 t it will serve during docking cargo vehicle, support EVAs, attaching modules or scientific containers to laboratory.
Tiangong-2 is equipped in two 490 N thrusters for orbit control and maneuvers during rendezvous, what is different solution comparing to ISS. Due the fact that laboratory is not able to provide conditions for constant presence of crew and spacecraft will not be docked to station permanently, Tiangong-2 was equipped in its own propulsion. For attitude control, laboratory is equipped in small thrusters controlled by navigation and 3 axis attitude control system based on star trackers and sun sensor. All onboard systems are powered by two deployable solar arrays and onboard Nickel-Metal-Hybrid 40 Ah batteries. Communication system is based on S and Ku band transponders; S band is dedicated for telemetry, Ku band transponder will serve for voice, video (from number of cameras installed inside and outside the station) and data downlink. Attitude controls, propulsion, tanks with 1000 kg of Monomethylhydrazine fuel and Nitrogen Tetroxide oxidizer, communication system and life support devices are installed in service module. Pressurized crew section is suitable for 3 crew members (with one astronaut sleeping inside Shenzhou docked to lab).