| FSW | ||
Designed to support both military and civilian earth observation needs, the FSW (Fanhui Shei Weixing, Recoverable Test Satellite) program began in 1966, with an initial launch failure in 1974. The original FSW-0 variant completed nine orbital missions during 1975-1987 after the maiden launch failure of November, 1974. The FSW-1 model was introduced in September 1987 (five flights), followed by the FSW-2 in August 1992 (three flights). The FSW-0 was conceived and developed in the late 1960's. It weighed about 1800 kg, and was launched by the CZ-2 booster from Jiuquan. Its normal orbit had an apogee height of 400 km, a perigee height of 200 km, and an inclination of 57 deg to 70 deg. The satellite employed three-axis attitude stabilization, and a solid-propellant retro-rocket for de-orbit prior to recovery. From 1975 to 1987, there were ten consecutive successful launches and recoveries of FSW-0. Different payloads were flown, including earth remote sensing and military reconnaissance using photographic film and CCD cameras. In 1987, during the mission FSW-9, the platform was also used as a microgravity research carrier for material science and biological science experiments. The results were promising; the microgravity level reached was 10-4 to 10-5 G during the on-orbit operation of the spacecraft. Launched by the CZ-2C booster from Jiuquan, the FSW-1 had a blunt conical shape with a length of 3.14 m, a maximum diameter of 2.2 m, and a mass of 2.1 metric tons. The vehicle was divided into two major sections: the equipment and retro module (1.6 m long) and the re-entry module (1.5 m long). The 3-axis-stabilised FSW-1 was powered by batteries and was controlled from the Xian Satellite Control Centre. The nominal flight duration was 7-10 days. FSW-1 photo reconnaissance satellites carried imaging payloads with a high resolution (10-15 m) camera loaded with film developed on Earth after recovery and a CCD (50-m resolution) camera system for near-real-time images. The CCD imager could also be used in directing the operation of the film camera, minimizing the wastage of film if the target was cloud-covered. The maximum recoverable payload was 180 kg; the maximum non-recoverable payload 250 kg. FSW-1 made five flights from September 9, 1987 to October 8, 1993. The FSW-2 debuted on 9 August 1992 with a launch by the new CZ-2D booster from Jiuquan. The heavier (2.5 to 3.1 metric ton) FSW-2 resembled the FSW-1 with an additional cylindrical module 2.2 m in diameter and 1.5 m long for a total length of 4.6 m. The major advantages of the newer model were an increased payload (350 kg maximum recoverable; 400 kg maximum non-recoverable) and a longer mission duration (up to 18 days). Unlike the FSW-1, the FSW-2 had a modest mono-propellant orbital maneuver capability. A reference was made in a 1989 scientific paper of a third generation of recoverable satellites that would be 'much larger, heavier, and more advanced than FSW-2'. The new spacecraft would also incorporate more sophisticated re-entry lift techniques to improve landing precision and to lessen deceleration forces, which were as high as 20 g's for FSW capsules. This design never materialized and it may have been related to the abortive manned capsule of the late 1970's. The FSW series seemed dead but in 2001 it was announced that China was to launch within a year the world's first 'Seeds Satellite'. The satellite would be a modified and simplified version of the FSW. Unnecessary equipment would be removed and the radiation shield modified to allow more cosmic rays to irradiate the seeds. Structural changes would be made to increase internal volume of the re-entry capsule. The satellite was to carry 300 kg of seeds of more than 1000 species. In August 1965, based on a proposed satellite development plan by Qian Xuesen, the Central Special Committee directed the Chinese Academy of Sciences (CAS) to begin implementation. Zhao Jiuzhang and Qian Ji were charged with conducting requirements analysis for recoverable satellites. Qian Ji's team toured relevant military and civilian units in order to determine applications of recoverable satellites. Beginning in March 1966 the Chinese Academy of Sciences convened the first in a series of conferences to coordinate technology for the Chinese space program. Over two months 120 delegates reviewed plans for several series of satellites, including selection of launch sites and necessary orbits and missions. As far as was publicly known, no decision was made in regard to manned spaceflight. The Science and Technology Commission for National Defense (STCND) instructed the CAS to conduct a forum on the results of the public meeting from May 11 to 25, 1966. China's satellite plans for the period 1966 to 1975 were presented to the involved military and civilian organizations. Zhao Jiuzhang provided the overview and Qian Ji presented preliminary plans for a retrievable satellite. The Chinese ten-year space plan provided for initial launch of satellites with scientific experiments. However the primary effort would be applied to development of a recoverable reconnaissance satellite. The first Chinese manned spacecraft would be based on the same recovery technology. Only later would a complete system of application satellites follow (for communications, meteorology, nuclear detonation detection, early warning of missile attack, and navigation). In June 1966 a recoverable satellite design group was formed within the Design Institute of Satellite Development (DISD). Wang Xiji was made Chief Designer for the spacecraft. He immediately began coordination of development of necessary spacecraft subsystems by various institutes. Shortly after the conference the Cultural Revolution began in earnest. Red Guards seized the Academy of Sciences. Key Chinese rocket scientists were denounced and persecuted. Development of satellites ground to a halt. Red Guards killed Zhao Jiuzhang, Director of the Institute of Geophysics, and Yao Tongbin. Qian Ji was accused of espionage. Qian Xuesen was reduced to the status of ordinary worker. Wang Xiji was criticized when a parachute failed to open during deployment experiments for a recoverable spacecraft. Only records proving that the spacecraft was not intentionally destroyed set him free. The extreme secrecy of the projects worked against the participants. Only after several months did Zhou Enlai intervene to put 15 key scientists in critical missile programs under state protection. The others had to fend for themselves as best they could. Despite the incredible disruptions, it was possible to hold a workshop to finalize the design for the recoverable satellite on September 11, 1967. Wang Daheng and Tao Hong were placed in charge of development of the space reconnaissance cameras and film for the satellite. By March 1968 the CAS Institute of Mechanics had completed the detailed analysis and tests necessary for engineering of the recoverable satellite. These included selection of the satellite's orbital trajectory; calculation of landing precision; determination of retrorocket requirements; studies of re-entry aerodynamics; selection of the external shape of the return vehicle; studies of aerodynamic drag and shear stress; and design of the heat shield. The Fourth Academy began development of the retrorocket. By the beginning of 1970 the CAS Institute of Automation had completed work on the recoverable spacecraft's 3-axis control system. This included technology tests, simulations on analogue and digital computers, and completion of a prototype of the system. The system used sun and earth sensors for orientation and an inertial measurement unit to guide the spacecraft on maneuvers. A cold gas thruster system would orient the spacecraft to the required position for photography or retrofire. On September 13, 1971, Mao's heir apparent, Minister of Defense Lin Biao, was killed in the crash of a Trident jet in Mongolia. The real background of the '913 Event' was obscure to this day, but Mao accused Lin Biao and his circle of planning a coup d'etat. The response was a witch hunt of Stalinist proportions. Over 1,000 senior officials at or above the rank of army commander were purged from the military. Investigative cadres placed everyone under suspicion. One result was that the project office for the related Shuguang-1 manned space capsule was closed. The development of the recoverable spacecraft continued at a sharply reduced pace and budget. China launched its first recoverable satellite on November 26, 1975, four years behind the original schedule. Immediately after launch it appeared that the satellite would be lost due to a loss of pressure of the gas orientation system. Qian Huesen believed the chance of a successful recovery was nil. However Yang Jiachi calculated that the pressure loss was simply due to heating of the spacecraft during ascent followed by the cooling in space. He believed a full-duration mission was possible. Nevertheless the decision was taken to bring down the spacecraft early, after three days of flight. Observers were deployed to the tops of 3400 m mountains to observe the descent of the capsule in Sichuan. The recovery force awaited orders. However the satellite was not seen. After some study the scientists determined that it probably landed on Chinese soil, in Guizhou. Meanwhile, at noon in Guizhou four coal miners were sitting in the mess hall when a red-hot ball was seen to fall from the sky and crash into a grove of trees. With great apprehension they ventured out to find a blackened hulk in a pit. Finally one threw a stone at the object, which bounced off with a metallic ding. Glad to find the thing to be of human artifice, the miners reported the matter to the authorities. The recovery force eventually arrived and found the interior of the spacecraft intact - usable film was recovered. The capsule for the FSW, like that of the US Discoverrer/KH-1 spy satellite, was mounted heat shield-forward on top of the launch vehicle. The ablative impregnated-oak nose cap covered electrical equipment. The spherical aft dome contained the recovery parachute. The film reels for the camera were located in an intermediate compartment. Although later touted for use as a microgravity spacecraft, the launch and recovery conditions were not appropriate. - 6 to 11 G's vertical, 2 G's lateral and 150 dB during launch, 8 to 20 G's on re-entry, and a landing speed of 4 to 14 m/s. The FSW-0 was equipped with a redundant flight control computer, an inertial measurement unit, and sun and earth sensors. Orientation was by a cold gas thruster system. Power came from 1300 Amp-hr / 27 V silver-zinc batteries. Flight duration was five days. Retrofire was accomplished by a spherical motor, 680 mm in diameter, 896.5 mm long. The motor provided 31.48 kN average / 40.66 kN maximum thrust for 18.5 seconds. For retrofire this provided a delta V of 340 m/s. Typical orbit: 177 x 521 km, 61.5 deg inclinaton. Length: 4.60 m (15.00 ft). Maximum Diameter: 2.20 m (7.20 ft). Span: 2.20 m (7.20 ft). Mass: 3,100 kg (6,800 lb). Payload: 750 kg (1,650 lb). Main Engine: FSW Retromotor. Main Engine Propellants: Solid. Spacecraft delta v: 100 m/s (320 ft/sec). Associated Launch Vehicle: CZ-2A, CZ-2C, CZ-2D. FSW Chronology
Bibliography and Further Reading
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