CZ-7 to make historical launch from Hainan

After decades of incremental improvements to its existing launch capabilities, the Chinese space programme is now undergoing a major technological overhaul, with the construction of new spacecraft and rocket fabrication facilities in Tianjin and a new space centre on the southern island of Hainan, as well as the introduction of an entire family of more capable launch vehicles burning non-toxic, non-polluting liquid propellants. Once fully operational, these new elements will bring China’s space programme into the 21st century, enabling space activities far more sophisticated and ambitious than those seen in the past four decades.

Test Launch Mission

As the first step of this revolutionary transformation, a test launch mission featuring two ‘Firsts’ will be conducted in June: it will be the maiden flight of China’s new-generation medium-lift Chang Zheng-7 (CZ-7) orbital launcher rocket, and also the debut launch mission conducted from the newly constructed Wenchang spaceport in Hainan. Preparation this historical mission began in late 2014, with a ground test vehicle of the CZ-7 rocket delivered from the Tianjin rocket fabrication facility to the Wenchang launch centre for a one-month simulated launch campaign in order to test the vehicle and all ground facilities.

Welding of the propellant tanks of the first flying CZ-7 vehicle, carrying the serial “CZ-7-Y1”, commenced in April 2015 and the vehicle rolled out of the production line in late April 2016. The seagoing rocket transport ship Yuanwang 21, carrying the segments of the launch vehicle inside specially-made containers, left the Port of Tianjin on 8 May. After nearly a week of voyage, the ship arrived at the Port of Qinglan on Hainan Island in the afternoon of 14 May.

Disembarkment of the launcher components began in the morning of 15 May and it took two days for all segments to be transported by road from the seaport to the launch centre. Next, the rocket segments were due to undergo a strict examination and checkout procedure at the launch centre’s technical area. Days before the launch, the assembled launch vehicle stack will be rolled out in a horizontal position atop a mobile launcher platform to Launch Pad 201, where it will be fuelled, checked, and launched.

CZ-7 Development

The development of the CZ-7 officially commenced in 2010, though the development of its liquid rocket engines began almost a decade before. China’s existing Chang Zheng series space launchers were all essentially derived from a single rocket design — the liquid-fuel DF-5 (CSS-4) intercontinental ballistic missile (ICBM) that first flew in 1971. The first-stage of the rocket is powered by a cluster of four parallel YF-20 engines, each producing 75 t (740 kN) of thrust at take-off. By adding four strap-on boosters and/or upper stages, the existing Chang Zheng series rockets can deliver up to 9,500 kg payload to LEO or 5,500 kg to GTO.

Heavy-lift rocket was one of the key systems outlined in China’s 863 Programme (State High-Tech R&D Initiative) in the 1980s. However, the Chinese space industry’s inability to produce a high-thrust rocket engine meant that the design could only exist in concept. This changed in the 1990s when China gained access to ex-Soviet space hardware and technologies, in particular the RD-120 rocket engine. The RD-120 was originally developed for the second-stage of the Russian Zenit family of launch vehicles in 1970s. It burns Kerosene (RG-1) as fuel and liquid oxygen (LOX) as oxidiser, producing nearly 100 t thrust. Development began in the early 2000s to produce two engines based on the RD-120 technology: the 120 t-thrust YF-100 and the smaller YF-115. Both engines became successful in the early 2010s, allowing the development of an entire family of new generation launch vehicles, including the heavy-lift CZ-5, the medium-lift CZ-7 and the small-load CZ-6.

The CZ-6 small-load launch vehicle, powered by a single YF-100 engine in its first-stage and a single YF-115 engine in its second-stage, made its maiden flight from the Taiyuan Satellite Launch Centre successfully on 20 September 2015, validating the design of both engines.

The basic variant CZ-7 is configured with a two-stage core vehicle with four strap-on boosters. The first-stage is powered by two YF-100 engines and each of the four strap-on boosters is powered by a single YF-100 engine. In together the six YF-100 engines can produce 734 t (7,200 kN) of thrust at lift-off. The rocket’s second-stage is powered by four YF-115 engines. Overall the launch vehicle is 53 m in length and weights 597 t, capable of delivering 13.5 t payload to LEO or 5.5 t to GEO. The CZ-7-Y1 mission will also be added with a Yuan Zheng-1 (YZ-1, “Expedition-1”) upper stage, designed to insert payload into a high orbit without the need to use the satellite’s own propulsion.

Crew Vehicle Re-entry Capsule

In the early years of its service life, the CZ-7 will mainly be used to launch the Tianzhou cargo resupply ship to support the construction of China’s space station in LEO. For the first flight test mission, the CZ-7-Y1 will carry a total of five mission payloads, including nanosatellites, satellite adapter, and dummy weight. However, the most significant revelation is that the payloads will include a scaled re-entry capsule, intended as a technology demonstrator for China’s next-generation multi-purpose crew vehicle that will eventually succeed the Shenzhou crew vehicle.

China Academy of Space Technology (CAST) has been quietly undertaking initial conceptual studies on the next-generation crew vehicle since at least 2014. A paper published in the January 2014 issue (Vol.35) of Chinese Journal of Aeronautics envisaged the future multi-purpose crew vehicle to be a capsule-type spacecraft, capable of carrying 2 to 6 astronauts to Earth orbit and beyond. The spacecraft vehicle is to be built in two versions sharing the same design but fitted with different propulsions: a 14-tonne version for LEO, Near Earth Asteroid and Mars missions, and a 20-tonne version for lunar landing missions.

The future crew vehicle can be launched atop either the CZ-7 or the heavier CZ-5 launch vehicle. It will be in a blunt cone shape, similar to that of the Boeing CST-100 or Orion CEV. Instead of the three-module arrangement of the current Shenzhou vehicle, the future crew vehicle will adopt a two-module arrangement, with a large inhabitable crew module at the front, and an uninhabitable cylindrical-shaped service module at back. The size of the re-entry vehicle will be twice of that of Shenzhou, capable of accommodating up to six crew members. A docking port and its associated docking sensors are fitted to the front-end of the crew module. The spacecraft can be fitted with two different service modules, with different propulsion systems and propellant capacities.

The future crew vehicle will also likely feature an integrated launch escape system, with solid rocket launch abort motors fitted on the service module to separate the entire spacecraft vehicle from the rocket launcher in case of emergency. The thermal shield of the future crew vehicle will be made from light weight ablator material, such as Phenolic Impregnated Carbon Ablator (PICA). The vehicle will be recovered using multiple parachutes, using either splashdown at sea or soft-landing in land.

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