China to launch Tiangong-2 in September ahead of new crew mission

by Rui C. Barbosa

China will make another big step in its manned space program with the launch of a new orbital laboratory and a new manned space mission in the next two months. The launch of the Tiangong-2 space station is expected to take place on September 15 via the use of a Chang Zheng (Long March) 2F/T2 rocket.

Launch Preps:

Despite the recent launch mishap of a Long March 4C rocket that resulted in the loss of the Gaofen-10 remote sensing satellite out of Taiyuan, China has remained undeterred in pressing forward with the launch campaign for its second orbital outpost.

2016-09-02-174008The rollout of module remains on target for September 13.

Engineers at the Jiuquan Satellite Launch Center have already been busy working on the rocket.

They are pressing through vertical integration operations on the Long March-2F/T2 launch vehicle that will be used to orbit the new Tiangong-2 orbital laboratory.

This launch campaign started back on July 9, with the arrival of Tiangong-2 to Jiuquan, following its journey from Beijing on July 7.

2016-09-02-171806The carrier then departed from Beijing on August 3, arriving at the launch site after a three-day train journey.

The rocket stages were then transported to the vertical assembly building and were subjected to initial testing to verify that no damage was suffered during train ride to the spaceport.

Electrical and autonomous tests followed, ahead of mounting the first stage on the mobile launch platform that will transport the rocket to the 921 Launch Platform on the LC43 Launch Complex.

After the first stage was secure on the mobile launch platform, engineers integrated the first of the four lateral strap-on boosters. Stacking operations have since moved on to the second stage.

Tiangong-2 (TG-2):

The new orbital outpost will enable the crews to remain in orbit for 30-day missions.

2016-09-02-172805Original built as a back up to Tiangong-1, TG-2 is expected to be identical in size to the previous Chinese station launched in 2011.

Having an increased payload capacity, the new station will use its improved living conditions to verify key technologies, such as on-orbit propellant resupply using the new Tianzhou logistics vehicle.

TG-2 will also be used to conduct space science experiments on a relatively large scale compared to China’s previous efforts.

Tiangong-2 will also be equipped with a new robotic arm and will be accompanied by the small Banxing-2 satellite for technology demonstrations. It will also capture images of the new station in orbit.

Launch Vehicle:

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.

2016-09-02-173234In 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.

2016-09-02-173620Like 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.

2016-09-02-172234The 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).

(Images via CCTV).

Related Articles