China and Materials Science 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 has no announced plans for developing a larger, dedicated microgravity satellite, although a second generation, multi-purpose recoverable vehicle is 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.
