Shenzhou-2 Experiment Racks Included Crystal Growth Furnace and Biological Systems
Beijing - Feb 23, 2001
The recent Shenzhou-2 (SZ-2) mission delivered a batch of life science experiments into orbit for a seven-day voyage in space last month and now reportedly back in the hands of scientists in Beijing.
An unidentified space officials told Reuters news agency on Jan. 18 that the SZ-2 Descent Module returned biological experiments, including live specimens, safely to Earth. The official said that there was a monkey, a dog and a rabbit on board among other biological specimens. Other space officials, however, did not confirm or comment on the report.
The returned experiment may also include those in the material science areas so scientists can find out if the microgravity environment has any effects on the experiment samples.
Although an extensive list of the life science and material science experiments was not available, China Space News, a major Chinese-language aerospace publication in China, published some details of the experiments in the Jan. 11 edition.
Among the material science experiments is growing crystals in a multi-chamber crystal growth furnace.
In space where convection and precipitation are significantly reduced, crystals form with more complete structure and higher quality than those grown on Earth.
Some of the crystals grown on the mission include crystals used in semi-conductors, oxidized monocrystals, and metallic alloys.
Scientists set up camera systems to image the entire crystal growth process. Primary interests are in studying the dynamics of crystal growth and how the near absence of convection affects the crystal growing process. Analyzing the imagery may shed light on why space crystals have better qualities than their Earth-based counterparts, and help improve the techniques of growing crystals on Earth.
In the life science experiments, there are 25 specimens known to be flown on the mission. Scientists at the Chinese Academy of Sciences (CAS) spent seven years to evaluate 87 proposed specimens and selected the 25 that earned a spot on SZ-2.
Of the 19 different types of biological systems in the flown specimens, seventeen are microorganisms, plants, aquatic organisms, and invertebrates while two kinds are cells and cellular structures from vertebrates.
The life science experiments examine space effects on biological organisms and a closed biological system. The experiments include studying cells and cellular structures, singular organism, multiple organisms interaction, and simple ecological system.
These experiments will help improve bioreactor technology, and refine techniques and technologies on controlling life cycle processes and maintaining lives in space. Application of the results and new knowledge may lead to producing high quality, high resistant and effective biological materials on Earth.
A set of life science experiments is on growing protein crystals. Scientists prepared 15 different kinds of enzyme and protein, such as Cytochrome b5, for the experiments.
Like the crystals in the material science experiments, protein crystals also grow larger and with more complete structures. By studying these space-grown crystals, scientists hope to gain a better understanding of their molecular structures which may lead to uncovering the secrets of protein, enzyme and some viruses.
Another area of the life science study is a broad series of experiments on space effects on biological systems. This is the first time China conducts an integrated study on multiple biological systems in a single space mission.
The subjects of this series of experiments are some of the known live biological specimens, for example, various types of algae, small snails, fruit flies, E. coli bacteria, and plants.
SpaceDaily previously reported that there were six mice on board. It was not clear if the mice were actually on SZ-2. However, one of the reports in China Space News said that cells and muscles from these pregnant mice were used in the experiments.
Dr. Liu Yongding, Payload Manager of the life science studies on this mission and a principal investigator of the life sciences experiments, said that the experiments involving the mice studied how the space environment might affect the response of an organism's neurological network to stimuli and any unusual substance that might be produced in the process.
Scientists extracted from the pregnant mice cardiac nerve and embryonic structures and placed them in the thigh muscle samples from the same mice. The samples were then immersed in containers with nutrients and placed in one of the two controlled environment growth chambers.
Both controlled environment growth chambers are 40 cm long, 31 cm wide and 24 cm high. Each chamber can house eight large and eight small sample trays. The large sample tray measures 5 cm (L) x 4 cm (W) x 10 cm (H) while the small tray has dimensions of 5 cm (L) x 2.7 cm (W) x 10 cm (H). Two identical chambers with the same experiment set up stay on Earth as control.
In the experiment involving small turtles, scientists extracted cardiac cells and kept them alive in the controlled environment growth chamber. The study examines how the space environment and different oxygen pressure level affects the cardiac cells. Results of the experiments will allow scientists to have a better understanding whether the same effects may have an impact on blood circulation in human during a spaceflight.
In the fruit fly experiment, the flies are housed in test tubes with nutrients filled at the bottom. According to China Space News, there are twice as many male flies as female because a male fruit fly tends to engage with more than one partner. The purpose of the experiment is to study reproduction and egg laying in the microgravity environment.
Various experiments involving plant seeds are contained in petri dishes in the controlled environment growth chambers. There are more than 10 types of seeds in these experiments, including seeds of asparagus and carrot.
Like the Shenzhou maiden mission, SZ-2 also carries seeds simply to expose them to space radiation. Chinese scientists claim that seeds which have been exposed to cosmic radiation yield superior quality produce.
On this flight 20,000 seeds of tomato, cucumber, cabbage and Chinese cabbage, weighing a total of 100 grams, from Shanghai got a ride in space.
Other seeds include glossy ganoderma fungus and Chinese caterpillar fungus from Tongzhoushi which is a neighbour city north of Shanghai in the Jiangsu Province; apple and pear seeds from Huludao City in the northeastern Liaoning Province; and from far reaches of the country seeds of wheat, potato, corn, other vegetables and flowers.
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