We can expect that Shenzhou-12 can be launched in the second half of 2017 with a crew of three.
The mission of Shenzhou-12 will be shorter of that of Shenzhou-11, but we might see an EVA from Tiangong-2 in another important step for the construction of the modular space station.
China will have to gain more extravehicular time before committing astronauts to help the construction of the modular station, and Tiangong-2 will be a perfect platform for that.
Launch Vehicle and launch site:
Tiangong-2 will be launched by the Long March-2G/T2, a variant of the launch vehicle usually used for the manned Shenzhou program.
This launch vehicle, developed by the China Academy of Launch Vehicle Technology under the China Aerospace Science and Technology Corporation, is different from the original ‘Shenjian’ (Devine Arrow) version that was developed from the Chang Zheng-2E launch vehicle.
That rocket, in turn, was based on the proven flight technology of the Chang Zheng-2C.
Conceptual design work on the CZ-2E launch vehicle began in 1986. The rocket was entered into the world launch services market following a successful test flight in July 1990.
In order to meet the requirements of the rendezvous and docking mission, the Chang Zheng-2F endured nearly 170 technical modifications and utilized five newly developed technologies.
A substantial difference for this rocket is the absence of the launch escape tower, a more bulbous fairing and an improved separation sequence.
On this upcoming mission, the fairing is 12.7 meters long and 4.2 meters in diameter. An additional characteristic of this rocket includes the fact that is capable of more precise orbit insertion accuracy.
This is possible with the introduction of improved navigation systems and complex guidance system that features real-time inputs to the rocket to orbit parameters and uses GPS data outside the measurement error correction parameters so as to achieve double redundancy. Also, more propellant is loaded on the boosters, thus increasing the firing time.
Like the CZ-2F/G, the CZ-2F/T2 is a two-stage launch vehicle that uses four strap-on boosters during the first stage phase.
Overall length is 52.0 meters with a 3.35 meter core stage and a maximum diameter of 8.45 meters. At launch, it has a 493,000 kg mass, capable of launching 8,600 kg cargos into a low Earth orbit.
For the CZ-2F launch vehicle, the LB-40 strap-on boosters have a length of 15.326 meters, a diameter of 2.25 meters, a gross mass of 40,750 kg and an empty mass of 3,000 kg.
Each booster is equipped with a fixed nozzle YF-20B engine that consumes UDMH/N2O4 developing 740.4 kN of sea lever thrust. Burning time is 127.26 seconds.
The L-180 first stage has a length of 28.465 meters, a diameter of 3.35 meters, a gross mass of 198,830 kg and an empty mass of 12,550 kg. It is equipped with a YF-21B engine pack that consists of four YF-20B engines that consume UDMH/N2O4 developing 2,961.6 kN of sea lever thrust. Its burn time is 160.00 seconds.
The L-90 second stage has a length of 14.223 meters, a diameter of 3.35 meters, a gross mass of 91,414 kg and an empty mass of 4,955 kg. It is equipped with a YF-24B engine pack that consists of one fixed nozzle YF-22B main motor with a swiveling vernier four YF-23B engines.
The engines consume UDMH/N2O4 developing 738.4 kN (main engine) and 47.07 kN (vernier) of vacuum thrust. Total burn time is 414.68 seconds (301.18 seconds burn time for the main engine).
Inaugurated on April 24, 1970 when the CZ-1 Chang Zheng-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A), the Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – is the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.
With ignition taking place at 14:04UTC at the end of the usual countdown in Chinese, the rocket will begin its journey into the Jiuquan night sky.
The separation of the four strap-on liquid boosters takes place at 155 seconds into the flight. The separation is followed by a stabilization process four seconds later, with the first stage separating right after together with stage two ignition.
Fairing separation takes place 3 minutes and 35 seconds into the flight. The second stage pushes Tiangong-2 into orbit, ending its performance at 9 minutes and 42 seconds. Spacecraft separation comes a few seconds later.
Once in orbit, Tiangong-2 will maneuver itself into an orbit about 380 kilometers above the Earth for initial tests. It will then transfer to a slightly higher orbit about 393 kilometers above Earth when Shenzhou-11will ferry two astronauts to the lab next October.
The site from where the rocket will depart includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.
Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. It is also the place from where all the Chinese manned missions are launched.
The LC-43 launch complex, also known by South Launch Site (SLS) is equipped with two launch pads: 921 and 603.
Launch pad 921 is used for the manned program for the launch of the Chang Zheng-2F launch vehicle (Shenzhou and Tiangong). The 603 launch pad is used for unmanned orbital launches by the Chang Zheng-2C, Chang Zheng-2D and Chang Zheng-4C launch vehicles.
Other launch zones at the launch site are used for launching the Kuaizhou and the CZ-11 Chang Zheng-11 solid propellant launch vehicles.
https://www.nasaspaceflight.com/2016/09/china-launch-tiangong-2-orbital-module/
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