Chang Zheng-2E (Long March-2E)

cz2e-2A rocket for commercial launches

In October 1985, the Chinese Ministry of Astronautics formally announced its intention to provide commercial satellite services for foreign customers using Chinese launch vehicles. However, the existing Chang Zheng launch vehicles were only capable of lofting 1,400 kg payload to the geostationary transfer orbit (GTO), far less than the mass of Western geostationary communications satellites being introduced at the time.

In early 1986, China Academy of Launch Vehicle Technology (CALT) developed a proposal to modify the CZ-2C launch vehicle by adding four liquid-fuelled strap-on boosters to the rocket’s first-stage. This would roughly double the rocket’s GTO payload capacity to 4,800 kg, about one-third of the capacity of the U.S. Space Shuttle and roughly the same capacity offered by the proposed Japanese H-2 launch vehicle.

The Challenger disaster in January 1986 and the subsequent grounding of the Space Shuttle seriously reduced the U.S. space launch capability. At the same time, the European Ariane rocket also suffered a number of launch failures, leaving a gap in the international commercial launch market. China was well positioned in the market since it would be able to offer a cheaper ride than its competitors at a time when many old commercial satellites were due to be replaced.

In February 1987, officials of the Ministry of Astronautics travelled to the United States to sign a letter of understanding with the satellite manufacturer Hughes Corporation (now Boeing Satellite) for launching its satellites using new CZ-2E launch vehicle. In September of the same year, China Great Wall Industry Corporation (CGWIC) won the bid to launch two Hughes HS-601 communications satellites for Optus, an Australian telecommunications company.

At the time all Chinese contractor had was CALT’s design and feasibility studies. The CZ-2E did not exist yet, and according to the agreement China only had 18 months before a required first test flight. A new launch complex (No.2) was under construction at the Xichang Satellite Launch Centre (XSLC) to support the launch of the heavier rocket. In addition, the Chinese government only agreed to fund the development of the CZ-2E through a commercial loan, adding further risks to the programme.

CALT eventually succeeded in meeting the target, with a flying rocket erected on the launch pad at the XSLC on 29 June 1990, only a day before the agreed target date. The rocket was successfully launched on 16 July 1990, placing a dummy HS-601 satellite and a Pakistani scientific experiment satellite Badr into orbits.

Design Features

The CZ-2E used as much mature technologies of the CZ-2C as possible. Primary modifications included four strap-on boosters each powered by a single YF-20B liquid engine. The first stage of the core vehicle is powered by a cluster of four YF-20B engines, collectively known as YF-21B. The stage was three meters longer than that of the CZ-2C to carry additional propellants. The second-stage was also based on the that of the CZ-2C, but carrying twice as much propellants. Finally, the launch vehicle featured an enlarged 4.2 m diameter payload fairing to accommodate the upper stage and the satellite. In conjunction with a LOX/LH2 or an EPKM solid perigee kick motor, the CZ-2E was capable of placing up to 4,500 kg payload to GTO.

A retired CZ-2E at the Xichang Satellite Launch Centre
A retired CZ-2E at the Xichang Satellite Launch Centre

Service History

The CZ-2E began its commercial operations on 22 March 1992, for the launch of Optus B1. When the countdown ended, two of the four main rocket engines of the core vehicle failed to ignite, leading an abort of the launch mission. A disastrous outcome which would have destroyed both the launcher/satellite and launch pad was only narrowly avoided. It then took the ground crew 39 hours to secure the rocket and retrieve the satellite. The same rocket was repaired and launched on 14 August of the same year, successfully placing Optus B1 into orbit.

The next flight four months later, on 21 December, failed when the satellite exploded inside the payload fairing only 45 seconds into the ascent, though the CZ-2E rocket continued flying and sent the debris of the satellite into the scheduled orbit. Later investigation suggested that the accident was caused by wind shear. The CZ-2E resumed flight two years later on 28 August 1994 successfully placing Optus B3 into orbit.

Disaster stroke again five months later on 26 January 1995, when a CZ-2E carrying another Hughes-built communications satellite APStar 2 exploded approximately 50 seconds into the flight. The failure was believed to have been caused by strong horizontal wind shear once the launch vehicle had cleared the mountains surrounding the launch site. Chinese engineers believed that the wind shear had caused a mechanical resonance that led to an explosion in the satellite’s apogee kick stage, while engineers in Hughes believed that the design flaw in the rocket’s payload fairing led to it collapsing under the force of the wind shear.

Exactly which side was responsible for the failure was inconclusive. Following the accident, some modifications were made to the rocket’s fairing design. The CZ-2E resumed flight on 28 November 1995, placing AsiaSat 2 into orbit. This was followed by another successful flight exactly one month later on 28 December, placing the TV-broadcast satellite EchoStar 1 into orbit.

However, the rocket suffered yet another blow on 4 September 1996, when Hong Kong-based Asia Satellite Telecommunications Co, owner of AsiaSat 2, filed an insurance claim of US$58 million for damage to AsiaSat 2 caused by an alleged rough ride during its launch in November 1995 by the CZ-2E. AsiaSat claimed that excessive acceleration caused by the launch vehicle knocked the antenna feed horns of the satellite’s nine Ku-band transponders out of alignment, reducing effective coverage and transmission power to the company’s customers.

By then many international customers had lost their patience and cancelled their geosynchronous launch contracts with the Chinese carrier. Furthermore, by 1996 a more advanced (and more powerful) geosynchronous launcher CZ-3B had been introduced into service. As a result the CZ-2E has never flown again.

In February 1999, CGWIC revealed the proposal for the CZ-2E(A), an improved variant of the CZ-2E with four stretched strap-on boosters to give a further increased payload capacity (13,000 kg to LEO). CGWIC announced that the rocket would be available as early as 2000. However, a lack of commercial customer finally led to the development being cancelled in the early 2000s.

CZ-2E(A) mockup in wind tunnel test
CZ-2E(A) mockup in wind tunnel test