CZ-7 makes successful maiden flight

At 20:00:07 local time (12:00:07 UTC) on 25 June 2016, a Chang Zheng-7 (CZ-7, or Long March 7) launch vehicle with a YZ-1A upper stage blasted off from Pad 201 at the China Wenchang Space Centre (CWSC) on Hainan Island in southern China. After 603 seconds of flight, the rocket successfully placed its payloads, including a scaled ballistic capsule for the future next-generation crew vehicle, into a 200 km by 394 km Low Earth Orbit (LEO).

(Images: Xinhua)

The historical mission came after years-long planning, development, constructing and testing, and marks the beginning of a new era in China’s space endeavour, with the simultaneous introduction of new spacecraft R&D facilities, a new spaceport, and an entire new family of launch vehicles based on common rocket engines. Once fully operational, these new elements will further expand China’s space launch capability, allowing heavier payload including space station modules and deep space probes to be lofted into orbit.

The introduction of the CZ-7 is also an important milestone in China’s effort to build a permanent space station on LEO – an ambitious programme initiated in 1992 and to be implemented in three stages over a timespan of 30 years. The first stage of the plan, with the aim to send human into space aboard the Shenzhou spacecraft vehicle, was concluded in 2006 after four unmanned test flights and two crewed missions. Currently the programme is in its second stage, aimed to develop and perfect advanced spaceflight techniques and technologies required for building an Earth-orbiting space station.

The CZ-7 will initially be used to launch the Tianzhou cargo ship to resupply China’s space station in orbit. However, once its technology matures the launch vehicle will be used to support other launch missions, including a man-rated version to launch the next-generation multi-purpose crew vehicle, which is currently in initial design stage.

The CZ-7 Launch Vehicle

In 2008, China Academy of Launch Vehicle Technology (CALT) revealed that Shenzhou 7 was to be the last mission launched by the basic variant CZ-2F launch vehicle, and two new improved variants were being developed to support follow-up missions in China’s human spaceflight programme – a modestly improved variant the CZ-2F/G featuring a new navigation package, and a radically upgraded variant the CZ-2F/H featuring a newly developed rocket engine burning a bi-propellant with kerosene as fuel and liquid oxygen (LOX) as oxidiser.

While the CZ-2/G entered service in 2011 for the launch of the Tiangong 1 space station module, and the subsequent Shenzhou 8, 9 and 10 missions. The CZ-2F/H project evolved into a completely new design, which was later given a new designation the CZ-7. The launch vehicle will share many technologies originally developed for the CZ-5 heavy-load launch vehicle, and is also built by the new rocket fabrication facility in Tianjin.

The basic variant CZ-7 is in a configuration of two-stage core vehicle with four strap-on liquid rocket boosters, powered by the newly developed YF-100 and YF-115 liquid rocket engines, both burning kerosene as fuel and liquid oxygen (LOX) as oxidiser. Without using an upper stage, the CZ-7 is able to place 13.5 t payload to a 400 km Low Earth Orbit (LEO), or 5.5 t payload to a 700 km Sun Synchronous Orbit (SSO).

Initially the CZ-7 will only be used to launch the Tianzhou cargo ship, but its designers hopes that the launch vehicle will eventually replace most designs in China’s existing Chang Zheng (Long March) launch vehicle family, including the CZ-2 series primarily intended for LEO missions from Jiuquan, the CZ-3 series for GEO missions from Xichang, and the CZ-4 series for SSO missions from Taiyuan. However, the launch vehicle will face some fierce competitions from its rivals, including the heavier CZ-5 from the same designer, and the (potentially more flexible) CZ-6A proposed by the Shanghai-based SAST.

The Launch Pad

Pad 201, from which the CZ-7 took off, is one of the two launch pads in the newly constructed Wenchang Space Launch Centre. Construction of the launch centre began in September 2009, and the launch complex facilities including launch pads, mobile launcher platforms, and vehicle assembly buildings became operational in 2014. A month-long simulated CZ-7 launch campaign using a non-flying ground test vehicle was conducted in late 2014.

The launch vehicle is delivered in segments by a specially designed Yuan Wang seagoing cargo ship from Tianjin on the east coast of China mainland to the Port of Qinglan on Hainan Island, where the segments are then transported by road to the launch centre. The segments are first examined in the horizontal checkout building, before being assembled and integrated with the payloads inside the 15-storey, 99.4 m-high steel-reinforced concrete Vehicle Assembly Building (VAB). Days before the launch, the assembled launch vehicle stack is rolled out in a vertical position atop a Mobile Launcher Platform, which moves on a rail track between the VAB and launch pad.

At the pad are a fixed umbilical tower, underground flame deflector trenches and ducts, and four lightning rods. Once the Mobile Launcher Platform carrying the launch vehicle stack arrives at the pad, the umbilical tower will move its swing arms and rotating platforms to embrace the vehicle, to allow the ground crew to inspect vehicle and carry out fuelling operation. The launch pads at Wenchang are the first in China to feature the Sound Suppression System, which sprays large volumes of water over the launcher platform and into the flame deflector trenches below it to dampen sound waves generated by the rocket engines, and also discouraged fires that might be caused by the rocket exhaust.

Future Missions

The CZ-7 test launch mission is only the first of a series of high-profile launch missions planned to take off from Wenchang over the next few years:

The heavier CZ-5 launch vehicle is due to make its debut flight in late September or early October this year;

A second CZ-7 launch is scheduled for early 2017, carrying China’s first cargo ship Tianzhou 1 for a test resupply mission with the Tiangong 2 laboratory module;

The Chang’e 5 lunar sample return mission is due to be launched by a CZ-5 in the second-half of 2017;

The CZ-5B will launch Tianhe 1, the core module of the Chinese Space Station, in 2018, followed by two laboratory modules and a space telescope module, all using the CZ-5B, between 2018 and 2022;

China’s first robotic Mars probe mission is due to be launched in 2020.

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