The CZ-1 (ChangZheng 1, or Long March 1 in its translation) was the PRC’s first space launch vehicle (LV), derived from the DF-4 (CSS-3) intermediate-range ballistic missile (IRBM). The three-stage launch vehicle was developed by 1st Space Academy (now China Academy of Space Launch Vehicle, CALT). The CZ-1 has carried out a total of three flight missions, with two being successful. The launch vehicle has sent the country’s first manmade satellite DFH-1 and second satellite SJ-1 into the orbit. An improved variant CZ-1D was tested in 1997.
1st Space Academy began to develop a three-stage launch vehicle to support the PRC’s space programme in late 1965. The CZ-1 LV were based on the first- and second-stage of the DF-4 IRBM, which carries Nitric acid (HNO3-27S)/UDMH liquid propellant. The third stage used a new-design FG-2 solid rocket motor. After shutdown of the second stage, the vehicle flew in a powerless glide for over 200 seconds before the third stage separated and ignited. An attitude control system using residual liquid propellant was added to the second stage to control the vehicle in zero-G during the coast. After separation of the second stage, the third stage was spun up to 180 rounds/min using a small spin rocket to keep it in stable flight.
CZ-1 on the launch pad at Jiuquan (Chinese Internet)
The campaign to launch China’s first satellite DFH-1 began on 1 April 1970, when two DFH-1 satellites and a CZ-1 launch vehicle arrived at the Jiuquan Satellite Launch Centre (JSLC) by railway. On the morning of 24 April 1970, weather forecast confirmed that the launch could go-ahead. The fuelling of the first- and second-stage of the launch vehicle with the liquid-propellant began at 05:40 in the morning and completed by 13:35 in the afternoon. The satellite was mated to the spin-stabilised solid-propellant third stage, and the launch site entered the final eight hours of launch preparation. The historical launch came at 21:35 local time, when the CZ-1 launch vehicle lifted-off from the launch pad. The launch vehicle pitched over to the southeast direction at T+18 seconds. 15 minutes later, the satellite was separated from the launch vehicle and entered orbit.
On 3 March 1971, the CZ-1 launch vehicle successfully sent the PRC’s second satellite, ShiJian-1 (SJ-1) scientific experimental satellite, into the orbit. This was also the last flight of the CZ-1, which was then replaced by the CZ-2.
CZ-1D
CALT developed an small launch vehicle known as CZ-1D in the late 1990s. The launcher was intended to fulfil the need of the commercial launch of small satellites (750~1,000kg) into Low Earth orbit (LEO). The launch vehicle features an improved first-stage and a redesigned second-stage for better performance. A CZ-1D with no payload was launched from the Taiyuan Satellite Launch Centre (TSLC) / Wuhai Missile Centre in November 1997, but no orbital mission has been carried out.
The CZ-1D has a modified first-stage that uses a YF-2A liquid-propellant rocket motor burning Nitric acid (HNO3-27S)/UDMH. The thrust has been increased from 1,020kN to 1,101.2kN. The original second-stage on the CZ-1 has been replaced by a new design that uses two YF-40 motors burning UDMH/N2O4. The third-stage has a new FG-36 HTPB solid motor and a DaFY2-1 control motor. The vehicle has also the obsolete cascade inertial guidance replaced by a new inertial guidance system using an onboard computer.
The CZ-1D is capable of delivering 800~1,000kg payload such as a recoverable satellite into the 200km LEO, or 350kg payload into the 903km sun-synchronous orbit. The satellite can be either spin-stabilised or three-axis stabilised.
Specifications
First launch: 24 April 1970 Last launch: 3 March 1971 (CZ-1), Nov 1997 (CZ-1D) Service status: Retired Overall length: 29.46m (CZ-1); 28.22m (CZ-1D) Diameter: 2.25m Launch weight: 81.31 tonnes (CZ-1); 81.075 tonnes (CZ-1D) Lift-off thrust: 1,020kN (CZ-1); 1,101.2kN (CZ-1D) Payload: 300kg to LEO (CZ-1); 800~1,000kg to LEO, or 350kg to SSO (CZ-1D)
