China and Materials Science in Space
The materials science research under microgravity environment in China has been conducted more than two decades. The Chinese satellite is a useful tool and was used for space materials experiments of microgravity since 1987. Many microgravity materials sciences have been performed on board the recoverable and spaceflight of Shenzhou (SZ). The primary purpose of studying activities on space materials science is to understand and develop applications of materials to be produced in microgravity, and to improve materials processing either on the ground or in space.
Since 1987 the PRC has utilized its FSW Earth observation recoverable capsule for both small materials science and life science experiments (Reference 321). The FSW-2 spacecraft which was first introduced in 1992 is also being offered to support microgravity research and with its greater capacity will probably succeed the FSW-1 as the principal carrier of such equipment. By the end of 1994, six FSW missions had carried domestic materials science experiments (References 789-791). The PRC had no announced plans for developing a larger, dedicated microgravity satellite, although a second generation, multi-purpose recoverable vehicle was under consideration.
Specific microgravity experiment limitations for the FSW-1 are 20 kg recoverable for piggyback payloads and 150 kg recoverable/150 kg nonrecoverable for a dedicated mission. Similarly, the FSW-2 offers a 300 kg recoverable payload capacity in addition to another non-recoverable 400-500 kg. Maximum flight time is approximately eight days for FSW-1 and 15 days for FSW-2.
Two drawbacks of the FSW-1 design are the high re-entry loads (up to 11 g's) and the moderate landing velocity (13-14 m/s). The European COSIMA payload flown in 1988 experienced fractures of a significant portion of the crystals grown in space, apparently due to harsh reentry and landing conditions. The FSW2 will feature less stressing impact loads. On orbit microgravity conditions are on the order of 10-4 - 10-5 g.
The domestic Chinese materials science research program appears to be still in its infancy. The first acknowledged payload for national interests was flown on FSW-0 9 (August, 1987). A general description of the Chinese experiments referred to smelting and recrystallization of alloys and semiconductor materials. Specifically, the Lanzhou Physics Institute is said to have performed work with yttrium-barium-copper superconductor samples. The FSW-1 1 mission the following month (September, 1987) also carried crystal growth experiments. Similar experiments were conducted on the 4th and 5th FSW-1 missions (1992 and 1993) and on both the FSW-2 flights (1992 and 1994).
In 1987 the state began to launch piggyback services in a planned and organized manner, opening up the field of space microgravity in China. The piggyback quality was increased gradually from several kilograms in its early days to 264.9 kg (excluding the weight of remote sensing, remote control, and other service systems) in the latest flight, equivalent to the launch of a sizable technological experimental satellite.
Space microgravity experiments are divided into two major categories, space materials and space biotic experiments. Many space materials experiments were carried out in the spatial multipurpose finishing stove, which was mainly used to experiment with gallium arsenide crystal growth. A total of 47 experiments with material samples were conducted, including the tests of crystal growth, the melting and solidification of alloys, superconducting materials, and material infiltration. On three occasions, alpha-lithium iodate crystal was successfully developed from supersaturated solid solution.
In space life science, 14 active piggyback experiments and a number of inactive tests were carried out. Among them were the spatial experiment with higher animals (guinea-pigs), three tests with protein crystal growth in space, experiments with the spatial controlled ecological and life support systems, and 10 tests in space biological effects.
Microgravity Science is a frontier interdisciplinary field emerging with the development of China manned space program, a hotspot in space sciences. The Key Laboratory of Microgravity of Chinese Academy of Sciences, founded as the National Laboratory of Microgravity in 1995 and renamed officially in 2008, has become the centers of microgravity science and of user supporting system in China.
Upon the guidance of national strategy of science and technology and national program of space science, the Lab is to strengthen the research bases and to establish the world-wide centers of microgravity science and of user supporting system with high reputation. While accomplishing the key national projects, the Lab is also to provide the technical supports required for China manned space program and to make the great contributions to the frontiers and interdisciplinary fields of microgravity sciences.
Japan and China have successfully organized the Microgravity Workshops. The primary focus of these conferences has been the development in the progress of space utilization in several areas related to science and technology. Apart from these objectives, the successful organization of the conferences has contributed immensely to the mutual friendship of these two countries. To further enhance the participation of other countries and increase the scope of the conference, the Korean microgravity community was welcomed in the year 2009.
Shijian-10
SJ-10 (Shi Jian = Practice in Chinese) is a technology demonstration and science mission of China. The overall objective is to conduct missions of space microgravity experiments in both fields of physical science and life science onboard the 24th recoverable satellite of China in LEO (Low Earth Orbit) for 2 weeks. Fruitful scientific results on microgravity science and space life science are expected to be contributed by this program.
The following institutions are involved in the SJ-10 program: Institute of Mechanics, Chinese Academy of Sciences, Beijing; Institute of Semiconductor, Chinese Academy of Sciences, Beijing; Tsinghua University, Beijing; Institute of Zoology, Chinese Academy of Sciences, Beijing; Institute of Physics, Chinese Academy of Sciences, Beijing; Institute of Engineering Thermophysics, Beijing; Dalian Maritime University, Dalian; Institute of Biophysics, Chinese Academy of Sciences, Beijing; Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai; Zhejiang University, Hangzhou.
Recoverable satellite Shijian-10, which was proposed by HU Wenrui, who is an academician of the Chinese Academy of Sciences, is designed for space experiment research of microgravity science and space life science. The major scientific objectives of Shijian-10 are to get innovative achievements in kinetic properties of matter and rhythm of life by carrying out various scientific experiments in space.
The satellite was to be launched by the Rocket of Long March-2D. The mass of the satellite is 3600 kg. The orbit inclination angle is 63°, the perigee altitude is 220 km, the apogee altitude is 482 km, and the operating lifetime is 15 days. 19 scientific experiments will be carried out onboard the satellite. Among them 10 experiments are for microgravity science research, and the other 9 experiments are for space life science research. These experiments are involved in 6 different fields: microgravity fluid physics, microgravity combustion, space materials science, space radiation biology, gravity biology, and space biotechnology.
The SJ-10 spacecraft of CAS was launched on April 5, 2016 (17:38 UTC) on a Long March 2D (CZ-2D) vehicle from the JSLC (Jiuquan Satellite Launch Center) in China's northwestern Gansu Province. The launch vehicle of Shijian-10 is capable of launching payloads up to 3,500 kg into orbit. Because SJ-10 did not need a payload fairing, given it is designed to withstand extreme thermal and aerodynamic environments on reentry, the performance of CZ-2D was increased sufficiently to lift the 3,600 kg satellite to orbit.
On April 18, 2016, the reentry capsule of China's first retrievable microgravity satellite, SJ-10, returned safely to Earth, marking a solid step forward in space science research and application. The recoverable capsule from the research probe, launched on April 6, touched down at around 8:30 UTC at the planned landing area in Siziwang Banner in north China's Inner Mongolia Autonomous Region, retrievers said.
SJ-10 is the second of four scientific satellites under a CAS space program. Unlike the other three, SJ-10 is returnable. It is the 25th such retrievable satellite launched by China in the past decades.
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