The Long March 1 (Chinese: 长征一号; pinyin: Chángzhēng Yīhào), also designated as Chang Zheng 1 (CZ-1), was a three-stage expendable carrier rocket developed by China as the inaugural vehicle in the Long March family of launchers. Derived from the Dong Feng 4 intermediate-range ballistic missile[1], it measured 29.86 meters in length and 2.25 meters in diameter, with a launch mass of 81.6 tonnes and a liftoff thrust of 112 tonnes. The first and second stages used liquid propellants—unsymmetrical dimethylhydrazine (UDMH) as fuel and red fuming nitric acid (RFNA, specifically AK27S) as oxidizer—while the third stage relied on solid propellant. Capable of delivering up to 300 kilograms to low Earth orbit at 440 km altitude, the rocket performed two successful launches from Jiuquan Satellite Launch Center in 1970 and 1971 before retirement, enabling China's entry into independent spaceflight by orbiting its initial satellites.[2][1][3]Development of the Long March 1 stemmed from China's missile research program initiated in 1956 under the broader Changzheng (Long March) initiative, adapting military ballistic technology for satellite launches to achieve self-reliance in space access.[2] The maiden flight occurred on April 24, 1970, successfully injecting the 173-kilogram Dong Fang Hong 1 satellite—China's first artificial satellite—into a 441 by 2,384 km elliptical orbit, broadcasting the revolutionary song "The East Is Red" and establishing the nation as the fifth worldwide to independently orbit a payload.[4][3] This mission, launched from Launch Area 2A at Jiuquan amid the Gobi Desert, celebrated annually as China's Space Day, highlighted the rocket's role in overcoming technological isolation during the Cold War era.[3]The second and final launch took place on March 3, 1971, deploying the 221-kilogram Shijian 1 satellite—a technology demonstrator for scientific experiments including radiation measurements—into an elliptical orbit of 266 by 1,826 km at 69.9° inclination.[5][6] Both missions achieved full success, validating the rocket's design despite its modest payload capacity compared to contemporary Western launchers like the U.S. Thor or Soviet R-7.[7] Following these flights, the Long March 1 was decommissioned in favor of more capable derivatives, such as the Long March 2, which incorporated improvements in staging and propulsion for sustained Chinese space ambitions, including crewed missions and deep-space exploration.[2]
Development
Historical Context
The Chinese space program originated in the mid-1950s under the newly formed Seventh Ministry of Machine Building, which oversaw early rocketry efforts heavily influenced by Soviet technical assistance until the 1960 Sino-Soviet split abruptly ended that collaboration.[8][9] In 1956, Qian Xuesen's report to the Central Military Commission prompted the establishment of the Committee on Science and Technology for National Defense, marking the formal inception of missile and space initiatives.[8] The Soviet Union provided critical support through the October 1957 New Defense Technical Accord, sharing expertise on ballistic missiles that formed the foundation for launch vehicle technology, though access remained limited amid rising tensions.[8] The 1960 split compelled China to achieve self-reliance, exemplified by the successful launch of the indigenous T-7M sounding rocket in February 1960, the country's first liquid-fueled rocket.[8]The Cultural Revolution (1966–1976) profoundly hampered progress, introducing severe delays through political purges of scientists and acute resource shortages that disrupted research and education.[8] Prominent figures like Zhao Jiuzhang, a leading satellite planner, were targeted, culminating in his suicide in October 1968, while broader campaigns against intellectuals led to the loss of institutional knowledge and talent.[8] Funding constraints and the closure of universities exacerbated these issues, postponing satellite projects originally envisioned in the late 1950s until the 1970s, though military oversight preserved some continuity in ballistic missile work.[8]Amid these challenges, a pivotal decision in January 1965 initiated the Long March 1 project, with Qian Xuesen advocating for an orbital launch vehicle derived from the Dong Feng 3 intermediate-range ballistic missile to enable independent satellite deployment.[10][11][12] The Central Special Committee approved this approach in March 1965, prioritizing it after China's atomic bomb test, with plans solidified by May 1966 for a 1970 launch.[10] Qian's leadership, as the program's architect, was instrumental in steering post-split efforts toward autonomy.[11] The core objective was to secure China's technological sovereignty by mastering satellite launches, thereby asserting national strength during Cold War rivalries with the United States and Soviet Union.[10]
Design and Engineering
The development of the Long March 1 launch vehicle was led by chief designer Wang Xiji starting in 1965, who oversaw the critical integration of a new upper stage to enable orbital insertion capabilities for payloads.[13] Under his direction, the project combined existing missile technologies with innovative adaptations to meet the demands of space launch, marking a pivotal shift from suborbital to orbital missions.[14]The core of the design involved adapting the single-stage liquid-fueled DF-3 intermediate-range ballistic missile into a three-stage orbital launch vehicle by adding a new liquid-fueled second stage and a solid-propellant third stage dedicated to payloadorbit insertion.[12] This modification leveraged the DF-3's proven first stage while addressing the need for precise velocity adjustments in the upper atmosphere, a requirement beyond the missile's original ballistic trajectory profile. Key engineering challenges included ensuring seamless compatibility between the liquid-fueled lower stages and the solid-propellant upper stage, which demanded rigorous interface testing to prevent ignition mismatches or structural vibrations during separation. Additionally, the payload fairing was engineered to provide robust aerodynamic and thermal protection for satellites during ascent, while guidance system upgrades—incorporating inertial navigation enhancements—were implemented to achieve the necessary precision for low-Earth orbit delivery, compensating for the DF-3's inherent ballistic inaccuracies.[15]Testing phases in the late 1960s encompassed extensive ground simulations and suborbital flights to validate the integrated design, including four full-thrust trials of the solid third-stage motor from May 1969 to January 1970. A notable suborbital test launch on November 16, 1969, ended in failure due to a second-stage program distributor malfunction, which caused the vehicle to crash after 69 seconds but provided essential data that refined the final configuration and reliability measures.[15]Among the key innovations were the retention of UDMH/AK-27S hypergolic propellants in the first two stages for their inherent storability and ignition reliability without complex ignition sequences, contrasting with earlier nitric acid-based systems. The third stage employed a polysulfide binder with ammonium perchlorate (AP) oxidizer in its solid propellant formulation, simplifying operations by eliminating the need for cryogenic handling or real-time fueling, thus enhancing overall mission readiness in resource-constrained environments.[1]
Vehicle Description
Overall Specifications
The Long March 1 is a three-stage, vertically integrated expendable launch vehicle without strap-on boosters, derived from the DF-4 intermediate-range ballistic missile for its initial two stages.[16][15] It measures 29.86 meters in height and 2.25 meters in diameter, with a launch mass of 81,600 kg.[16] The vehicle was compatible with the early infrastructure at the Jiuquan Satellite Launch Center in Inner Mongolia, including mobile service towers for payload integration and countdown operations.[16][17]In terms of performance, the Long March 1 had a payload capacity of 300 kg to low Earth orbit (LEO) at inclinations compatible with Jiuquan's latitude, with demonstrated capabilities for higher orbits up to medium Earth orbit (MEO) altitudes in operational flights.[16] The first stage generated a sea-level thrust of 1,101.2 kN using four YF-2A engines burning unsymmetrical dimethylhydrazine (UDMH) and red fuming nitric acid (RFNA), providing an overall specific impulse of approximately 242.5 seconds at sea level and 267.4 seconds in vacuum for the ascent phase.[18] The vehicle's burn sequence supported liftoff and initial ascent over roughly 130 seconds for the first stage, followed by upper-stage burns totaling about 164 seconds to achieve orbital insertion.[15][18]
Stage Configuration
The Long March 1 (CZ-1) was a three-stage launch vehicle designed to deliver small payloads into low Earth orbit, with the first two stages employing liquid propulsion for initial ascent through the atmosphere and the third stage using solid propulsion for final orbit insertion. The stages were integrated with interstage structures to facilitate sequential ignition and separation, guided by an inertial navigation system throughout the flight.[15][18]The first stage utilized a liquid-fueled YF-2A engine cluster consisting of four fixed chambers, burning unsymmetrical dimethylhydrazine (UDMH) as fuel and AK-27S (a red fuming nitric acid oxidizer) as the oxidizer. Measuring 17.84 meters in length and 2.25 meters in diameter, it provided the initial thrust for liftoff, generating 1,101 kN at sea level with a specific impulse of approximately 241 seconds at sea level. This stage was responsible for propelling the vehicle to an altitude of about 60 km over a burn time of roughly 130 seconds.[15][18][1]The second stage, also liquid-fueled with UDMH/AK-27S propellants, employed a single YF-3A engine and measured 5.35 meters in length with the same 2.25-meter diameter. It delivered a vacuum thrust of 323 kN and a specific impulse of 287 seconds in vacuum, operating for about 126 seconds to achieve exo-atmospheric velocities.[15][18][19] This stage's vernier thrusters enabled attitudecontrol during coast phases using residual propellants.The third stage featured a solid-propellant motor designated FG-02 (or GF-02), using a polysulfide and ammonium perchlorate (AP) composite propellant, with a length of 3.95 meters and a reduced diameter of 0.77 meters. It produced 181 kN of thrust and a specific impulse of 254 seconds over a 38-second burn, enabling final orbital circularization. The stage was spin-stabilized at 180 rpm to provide gyroscopic stability without active control systems.[15][18][1]
Stage
Propulsion Type
Propellants
Length (m)
Diameter (m)
Thrust (kN)
Specific Impulse (s)
Primary Function
First
Liquid (YF-2A, 4 chambers)
UDMH/AK-27S
17.84
2.25
1,101 (SL) / 1,225 (vac)
241 (SL) / 268 (vac)
Liftoff and atmospheric ascent[15][18]
Second
Liquid (YF-3A)
UDMH/AK-27S
5.35
2.25
323 (vac)
287 (vac)
Exo-atmospheric injection[15][18][19]
Third
Solid (FG-02)
Polysulfide/AP composite
3.95
0.77
181 (vac)
254 (vac)
Orbital circularization and spin stabilization[15][18][1]
Stage separation was achieved using pyrotechnic bolts and spring-pushers to jettison expended sections, ensuring clean disengagement and minimal interference with subsequent ignitions, supported by the vehicle's strap-down inertial guidance. The payload was integrated atop the third stage within a conical fairing of approximately 2.25 meters in diameter, designed to enclose satellites up to 300 kg for delivery to a 440 km low Earth orbit.[15][18]
Operational History
1970 Launch
The inaugural operational flight of the Long March 1 occurred on April 24, 1970, from Site 2 (LA-2) at the Jiuquan Satellite Launch Center in China's Gansu Province.[20] This launch marked the debut of the full three-stage configuration in an orbital mission, deploying China's inaugural experimental satellite, Dong Fang Hong 1.[21] The payload, weighing 173 kg and measuring 1 meter in diameter, featured a radio transmitter that broadcast the revolutionary song "The East is Red" along with telemetry data to demonstrate satellite communication capabilities.[20][22]The mission executed successfully, with the rocket achieving liftoff using its first-stage liquid-fueled engine, followed by nominal stage separations and second- and third-stage burns.[21] The second stage, employing hypergolic propellants (UDMH and RFNA), and the solid-propellant third stage demonstrated reliable performance, including in-flight ignition under vacuum conditions for the second stage, validating the design's robustness for orbital insertion without ground support. Dong Fang Hong 1 was injected into an elliptical low Earth orbit with a perigee of 441 km, an apogee of 2,384 km, and an inclination of 68.4°—higher than the initially targeted low Earth orbit due to performance margins in the upper stages.[23][24]Post-separation telemetry from ground stations confirmed the satellite's stable orientation and activation, with its signals receivable across China for 20 days until the onboard batteries were depleted.[22] This operational duration exceeded expectations for the experimental power system, providing critical data on orbital environment and transmission reliability while affirming the Long March 1's viability for future missions.[20] The success positioned China as the fifth nation to independently achieve orbital launch capability.[21]
1971 Launch
The second and final operational flight of the Long March 1 rocket took place on March 3, 1971, from Launch Complex 2 (Site 502) at the Jiuquan Satellite Launch Center in China.[5][6] The mission successfully deployed China's Shijian 1 satellite, marking a key step in the nation's early scientific space endeavors.[25]Shijian 1 was a 221 kg spacecraft equipped for environmental studies, featuring instruments such as a Geiger-Müller counter and a BE-window ionization chamber to measure cosmic rays, solar X-rays, and particles in the inner radiation belt.[5][6] The satellite was inserted into an elliptical low Earth orbit with a perigee of 266 km, an apogee of 1826 km, and an inclination of 69.9°.[5][6] All rocket stages performed nominally, and post-deployment confirmation came from ground-based tracking stations monitoring the satellite's signal and trajectory.[25]Following separation, Shijian 1 transmitted data continuously, exceeding its one-year design life by operating successfully for eight years until it ceased transmissions in 1979, with no significant anomalies noted during its mission.[5][6] This flight demonstrated enhanced operational reliability over the inaugural 1970 launch, achieving a lower perigee altitude that facilitated more effective data collection on the space environment.[25]
Retirement and Legacy
Decommissioning
The Long March 1 was retired in March 1971 immediately after its second and final launch on March 3, which successfully placed the ShiJian-1 satellite into orbit.[3] This decision stemmed primarily from its limited payload capacity of 300 kg to low Earth orbit, which proved inadequate for China's growing requirements to deploy heavier and more complex satellites.[26]Central to these limitations was the vehicle's derivation from the DF-4 intermediate-range ballistic missile, whose two-stage liquid-propellant design, when augmented with a rudimentary solid-propellant third stage, suffered from inefficiencies in thrustcontrol, orbital insertion precision, and overall scalability for advanced missions.[8] The solid third stage, in particular, provided inconsistent performance due to its basic technology, hindering the rocket's ability to support evolving space objectives beyond initial proof-of-concept demonstrations.[26]With no additional flights planned, the Long March 1's operational life ended by late 1971, marking the cessation of its production and the repurposing of remaining hardware for ground testing or storage.[3] Production resources were swiftly redirected to the development of the Long March 2, a more powerful successor based on the DF-5 missile, without any efforts to pursue upgrades or variants for the original design.[26]This rapid decommissioning unfolded against the backdrop of severe economic and political constraints imposed by the Cultural Revolution, which disrupted scientific endeavors and compelled prioritization of versatile, higher-capacity launch vehicles to align with national priorities.[8]
Significance
The successful launch of Dong Fang Hong 1 aboard Long March 1 on April 24, 1970, marked a pivotal milestone in China's space program, establishing the nation as the fifth country—following the Soviet Union, the United States, France, and Japan—to independently place a satellite into orbit.[27] This achievement, accomplished amid economic hardship and political turmoil during the Cultural Revolution, underscored China's determination to achieve technological self-reliance after the withdrawal of Soviet assistance in 1960.[28] The event significantly boosted national prestige, symbolizing a triumph of indigenous innovation and elevating the global standing of the Chinese people, as evidenced by contemporary accounts of heightened pride among overseas Chinese communities.[29]Technologically, Long March 1 demonstrated the feasibility of adapting military ballistic missiles for civilian space launch, with its first two stages derived from the Dong Feng 4 intercontinental ballistic missile.[30] This conversion proved instrumental in shaping the broader Long March rocket family, providing foundational engineering principles and propulsion expertise that informed subsequent vehicles, such as Long March 2, which was based on the Dong Feng 5 missile and enabled heavier payloads for recoverable satellites and early manned missions.[31] Operationally, the launches from Jiuquan Satellite Launch Center solidified its role as China's primary site for orbital missions, hosting the majority of early satellite deployments and later supporting key programs like the Shenzhou manned flights.[32] The program also cultivated a core cadre of engineers and scientists whose experience in liquid-fueled rocketry and mission control laid the groundwork for advanced endeavors, including the development of the China Manned Space Program.[28]Despite its successes, the early secrecy surrounding China's space efforts—driven by national security concerns during the Cold War—restricted international awareness and collaboration until the 1980s.[33] Following the 1971 launch, resources shifted toward developing heavier-lift capabilities like Long March 2, with no further upgrades or flights documented for Long March 1 due to its limited payload capacity of around 300 kilograms to low Earth orbit.[3] As of 2025, Long March 1 is commemorated in Chinese space history as the initiator of self-reliant orbital access, with April 24 observed as National Space Day since 2016 to honor its legacy; however, its obsolescence in the era of reusable and heavy-lift rockets precludes any revival.[28]