Progress in Research on Materials Under Microgravity in China

Research on materials under microgravity in China began in the 1980s, sparked by Prof. Lanying Lin (academician of CAS), Prof. Xiji Wang (academician of CAS), Prof. Guirong Min (academician of CAS), and Prof. Huabao Lin (academician of CAS), and others. The first semiconductor crystal, first optical crystal, and first alloys were grown in space on board a recoverable satellite in 1987. Since then, microgravity materials science became a new scientific branch in China.Scientific and technical activities on space crystal growth and solidification are carried out through two major programs: ground-based studies and orbital experiments. The main results obtained during 2001-2003 are reported below.     

应用空间原子钟的基础物理测试

随着新型原子钟的发明,其频率稳定度性能已经发展到很高的水平,它们在空间科学试验中将发挥重要作用。这篇文章将介绍应用空间原子钟在微重力环境下所建议的某些基础物理方面的测试。     

中国微重力科学研究回顾与展望

微重力科学主要研究微重力环境中物质运动的规律,以及不同重力环境中重力对物质运动的影响.中国微重力科学研究起步于20世纪60年代,兴起于80年代中后期,经过多年发展,目前已初具规模,在一些重要方向具有明显特色和一定优势.本文回顾了中国微重力科学研究的早期历程,评述了近年来中国微重力科学研究进展,特别是利用实践十号科学实验卫星、天宫二号空间实验室等空间平台开展的微重力科学与技术应用研究取得的最新成果,并对中国载人空间站时代微重力科学发展的前景予以瞻望,推动微重力科学与应用研究在中国的快速、可持续发展.     

Progress on Solar Physics Research in China

The progress on Chinese Space Solar Telescope (SST) in 2002-2004 is introduced. The documentations on plans and outlines based on the standards of Chinese aerospace industry for SST mission has been fulfilled. The key technical problems of SST satellite platform and payloads are tackled during pre-study stage of the mission. The laboratory assembly and calibration of the main optical telescope of 1.2 m spherical mirror and 1 m plain mirror have been carried out with the accuracy of λ/40 and λ/30, respectively. The prototype at 17.1 nm for extreme ultraviolet telescope is under development and manufacture with a diameter of 13 cm. Its primary and secondary mirrors have a manufacturing error of 5 nm with a roughness degree of less than 0.5 nm and a multiplayer reflection factor of better than 20%. The on-board scientific data processing unit has been developed. Prototypes for other payloads such as H. and white light telescope, wide band spectroscopy in high energy and solar and interplanetary radio spectrometer have been developed accordingly.     

挡板对液体推进剂晃动力的影响

研究了全尺度重力探测卫星－Ｂ贮箱对于安装档板和不安装挡板情形下液体推进剂晃动的液体动力特性。结果显示,以重力瞬变加速度和重力梯度加速度为作用力的轨道加速度使液体推进剂产生了晃动,安装挡板使晃动幅度减小。由于推进剂在贮箱中上下运动的同时伴随着左右运动而产生了作用于贮箱上的力,通过液体推进剂与贮箱壁面的应力关系计算了作用在贮箱上的力。计算模拟结果显示,挡板产生的阻尼在减少流体晃恸 的同时也减少了流体作     

模拟微重力对人骨髓间充质干胞向成骨细胞分化中细胞信号通路影响的分析

通过模拟来研究微重力对hMSC向成骨细胞分化的影响,并利用相关信号通路的激活剂或抑制剂来调节这一分化过程．研究结果表明,在成骨细胞分化诱导条件下,微重力降低了hMSC向成骨细胞定向分化的能力,并且成骨细胞标记性基因的表达明显降低,Runt相关转录因子2（Runx2）的表达受到抑制．相反,过氧化物酶体增殖激活受体γ（PPARγ2）的表达则增加．同时,微重力也降低了ERK的磷酸化水平,而增加了p38MAPK的磷酸化水平．使用p38MAPK的抑制剂SB203580能够抑制p38MAPK的磷酸化,但不能降低PPARγ2的表达水平．骨形态发生蛋白（BMP）能增加Runx2的表达水平．成纤维细胞生长因子2（FGF2）增加了ERK的磷酸化水平,但也不能显著增加成骨细胞标记性基因的表达水平．采用BMP,FGF2和SB203580三种因子组合来调控微重力下的成骨细胞分化能力,结果表明三者的协同作用能显著逆转微重力对成骨细胞定向分化的生物学效应．研究结果还说明,模拟微重力应该是通过不同的细胞信号通路来抑制成骨细胞分化和提升脂肪细胞分化的．     

Experiments in materials science on the ground and in reduced gravity using electrostatic levitators

To counter residual accelerations, dedicated levitators or positioners are necessary to support a host of materials science experiments on the ground and in microgravity. All levitators (e.g., aerodynamic, acoustic, electromagnetic, electrostatic, optical) have their own merits and limitations but the electrostatic scheme offers the combined advantages of processing millimeter-size objects, independent heating, quasi-spherical shape of molten materials, handling of materials under extreme temperatures for hours, virtually convection-free samples, and wide view around the samples for diagnostic. These attributes provide unique research opportunities in materials science on the ground as well as under reduced gravity. In particular, electrostatic levitators are very attractive to measure the physical and structural properties of equilibrium and non-equilibrium liquids, to synthesize multi-function materials, and to understand metastable phase formation, vitrification, and diffusion. In this paper, research and development carried out by the Japan Aerospace Exploration Agency over the years in the field of electrostatic levitation are summarized and the main results obtained in materials science are presented.     

微重力环境下蓄液器流体蓄留特性的试验研究

为验证板式贮箱蓄液器的蓄液性能,搭建了蓄液器模型试验系统,针对蓄液器模型的蓄液性能和流体传输行为进行微重力落塔试验研究,得到微重力环境下蓄液器的流体蓄留和传输规律.试验结果表明,相对于楔形蓄液器,双圆锥形蓄液器具有更好的蓄液能力,对于双圆锥形蓄液器,承受侧向加速度时仍具有良好的蓄液能力,合理设计蓄液器结构可有效地蓄留液体并控制液体传输速度.该试验成果不仅为新型板式流体管理部件设计优化提供参考,同时也为空间环境下流体控制提供了一种新方法.     

The effect of the space flight environment on mucin production in the mouse uterine tube

Numerous studies have indicated that the microgravity environment of space has harmful effects on several tissues throughout the body. Although this phenomenon is well documented, research in this area is still in its relative infancy. This study investigates the effects of space flight on mucin production of the uterine tubes of mice. This study examined the epithelium of the uterine tubes from female mice that were flown on the space shuttle Endeavour for 13 days in August, 2007 and their concomitant controls. The tissue was qualitatively analyzed for the type of mucin produced, i.e., acidic, neutral, acidic/neutral mixture. Further, the tissue was quantitatively analyzed for the amounts of mucins produced by measuring the thickness of the mucin layer for each region of the uterine tube: isthmus, ampulla, and infundibulum. One way ANOVA tests were used to compare mucin thickness between all three sets of animals. Results indicate similar but not identical results between the three regions of the uterine tube. The Baseline tissue had the thickest mucin layer regardless of treatment group. In the ampulla the mucin layer was the thinnest in the Flight tissue, followed by the Ground Control, with the Baseline being the thickest. Analysis of the mucin layer of the infundibulum of the three treatment groups indicated no difference in its thickness between the three regions of the uterine tube. These results indicate a trend toward thinning of the mucin layer of the uterine tube in space flight, but also indicate an influence by the housing environment.     

3D information from 2D images recorded in the European Modular Cultivation System on the ISS

The European Modular Cultivation System (EMCS) on the ISS allows long-term biological experiments, e.g. on plants. Video cameras provide near real-time 2D images from these experiments. A method to obtain 3D coordinates and stereoscopic images from these 2D images has been developed and is described in this paper. The procedure was developed to enhance the data output of the MULTIGEN-1 experiment in 2007. One of the main objectives of the experiment was to study growth movements of the Arabidopsis plants and the effect of gravity on these. 3D data were important during parts of the experiment and the paper presents the method developed to acquire 3D data, the accuracy of the data, limitations to the technique and ways to improve the accuracy. Sequences of 3D data obtained from the MULTIGEN-1 experiment are used to illustrate the potential of this newfound capability of the EMCS. In the experiment setup, a positional depth accuracy of about ±0.4 mm for relative object distances and an absolute depth accuracy of about ±1.4 mm for time dependent phenomena was reached. The ability to both view biological specimens in 3D as well as obtaining quantitative 3D data added greatly to the scientific output of the MULTIGEN-1 experiment. The uses of the technique to other researchers and their experiments are discussed.     

Improvements in and actual performance of the Plant Experiment Unit onboard Kibo,the Japanese experiment module on the international space station

In 2004, Japan Aerospace Exploration Agency developed the engineered model of the Plant Experiment Unit and the Cell Biology Experiment Facility. The Plant Experiment Unit was designed to be installed in the Cell Biology Experiment Facility and to support the seed-to-seed life cycle experiment of Arabidopsis plants in space in the project named Space Seed. Ground-based experiments to test the Plant Experiment Unit showed that the unit needed further improvement of a system to control the water content of a seedbed using an infrared moisture analyzer and that it was difficult to keep the relative humidity inside the Plant Experiment Unit between 70 and 80% because the Cell Biology Experiment Facility had neither a ventilation system nor a dehumidifying system. Therefore, excess moisture inside the Cell Biology Experiment Facility was removed with desiccant bags containing calcium chloride. Eight flight models of the Plant Experiment Unit in which dry Arabidopsis seeds were fixed to the seedbed with gum arabic were launched to the International Space Station in the space shuttle STS-128 (17A) on August 28, 2009. Plant Experiment Unit were installed in the Cell Biology Experiment Facility with desiccant boxes, and then the Space Seed experiment was started in the Japanese Experiment Module, named Kibo, which was part of the International Space Station, on September 10, 2009 by watering the seedbed and terminated 2 months later on November 11, 2009. On April 19, 2010, the Arabidopsis plants harvested in Kibo were retrieved and brought back to Earth by the space shuttle mission STS-131 (19A). The present paper describes the Space Seed experiment with particular reference to the development of the Plant Experiment Unit and its actual performance in Kibo onboard the International Space Station. Downlinked images from Kibo showed that the seeds had started germinating 3 days after the initial watering. The plants continued growing, producing rosette leaves, inflorescence stems, flowers, and fruits in the Plant Experiment Unit. In addition, the senescence of rosette leaves was found to be delayed in microgravity.     

Preliminary results of space experiment: Implications for the effects of space radiation and microgravity on survival and mutation induction in human cells

In view of the concern for the health of astronauts that may one day journey to Mars or the Moon, we investigated the effect that space radiation and microgravity might have on DNA damage and repair. We sent frozen human lymphoblastoid TK6 cells to the International Space Station where they were maintained under frozen conditions during a 134-day mission (14 November 2008 to 28 March 2009) except for an incubation period of 8 days under 1G or μG conditions in a CO₂ incubator. The incubation period started after 100 days during which the cells had been exposed to 54 mSv of space radiation. The incubated cells were then refrozen, returned to Earth, and compared to ground control samples for the determination of the influence of microgravity on cell survival and mutation induction. The results for both varied from experiment to experiment, yielding a large SD, but the μG sample results differed significantly from the 1G sample results for each of 2 experiments, with the mean ratio of μG to 1G being 0.55 for the concentration of viable cells and 0.59 for the fraction of thymidine kinase deficient (TK⁻) mutants. Among the mutants, non-loss of zygosity events (point mutations) were less frequent (31%) after μG incubation than after 1G incubation, which might be explained by the influence of μG on cellular metabolic or physiological function. Additional experiments are needed to clarify the effect of μG interferes on DNA repair.     

Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring (Gallus gallus domesticus)

Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring (Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7 days space flight. And the control group has the same clan with the flight group. PGCs from flight and control group silk chicken offspring embryos were examined during migration by using two antibodies (2C9 and anti-SSEA-1), in combination with the horseradish peroxidase detection system, and using periodic acid-Schiff’s solution (PAS) reaction. After incubation for about 30 h, SSEA-1 and 2C9 positive cells were detected in the germinal crescent of flight and control group silk chicken offspring embryos. After incubation of eggs for 2–2.5 days, SSEA-1 and 2C9 positive cells were detected in embryonic blood vessels of flight and control group silk chicken offspring embryos. After incubation of eggs for 5.5 days, PGCs in the dorsal mesentery and gonad could also be identified in flight and control group silk chicken offspring embryos by using SSEA-1 and 2C9 antibodies. Based on location and PAS staining, these cells were identified as PGCs. Meanwhile, at the stage of PGCs migration and then becoming established in the germinal ridges, no difference in SSEA-1 or 2C9 staining was detected between female and male PGCs in flight and control group silk chicken offspring embryos. Although there were differences in the profiles of PGC concentration between male and female embryos during the special circulating stage, changing profile of PGCs concentration was similar in same sex between flight and control group offspring embryos. We concluded that there is little effect on PGCs in offspring embryos of microgravity-treated chicken and that PGC development appears to be normal.     

National Report on Space Medicine Progress in 2012–2014

The application of manned spaceflight makes a great impetus on the development of space medicine. With the deep growth of Chinese manned space, our national space medicine has attained great achievements. In this paper, the basic research of Space Medicine and its application in China during 2012–2014 were briefly reviewed.     

Some Investigations on the Ionosphere during 2012–2014 in China

In this national biannual report, we will outline some recent progresses in ionospheric studies conducted by Chinese scientists since 2012. The mentioned aspects include: the solar activity control of the ionosphere; couplings between the ionosphere, lower atmosphere and plasmasphere;ionospheric climatology and disturbances; ionospheric irregularities and scintillation; models, data assimilation and simulations; unusual phenomena of the ionosphere; possible seismic signatures presented in ionospheric observations, and some methodology progresses. These progresses will enhance our ability to observe the ionosphere, provide more reasonable understanding about the states of the ionosphere and underlying fundamental processes, and stimulate ionospheric modeling, forecasting and related applications.     

Crustal deformation characteristics of Sichuan-Yunnan region in China on the constraint of multi-periods of GPS velocity fields

In order to obtain deformation parameters in each block of Sichuan-Yunnan Region (SYG) in China by stages and establish a dynamic model about the variation of the strain rate fields and the surface expansion in this area, we taken the Global Positioning System (GPS) sites velocity in the region as constrained condition and taken advantage of the block strain calculation model based on spherical surface. We also analyzed the deformation of the active blocks in the whole SYG before and after the Wenchuan earthquake, and analyzed the deformation of active blocks near the epicenter of the Wenchuan earthquake in detail. The results show that, (1) Under the effects of the carving from India plate and the crimping from the potential energy of Tibetan Plateau for a long time, there is a certain periodicity in crustal deformation in SYG. And the period change and the earthquake occurrence have a good agreement. (2) The differences in GPS velocity fields relative Eurasian reference frame shows that the Wenchuan earthquake and the Ya'an earthquake mainly affect the crustal movement in the central and southern part of SYG, and the average velocity difference is about 4–8?mm/a for the Wenchuan earthquake and 2–4?mm/a for the Ya'an earthquake. (3) For the Wenchuan earthquake, the average strain changed from 10 to 20 nanostrian/a before earthquake to 40–50 nanostrian/a after the earthquake, but before and after the Ya’an earthquake, the strain value increased from about 15 nanostrian/a to about 30 nanostrian/a. (4) The Wenchuan earthquake has changed the strain parameter of each active block more or less. Especially, the Longmen block and Chengdu block near the epicenter. The research provides fundamental material for the study of the dynamic mechanism of the push extrusion from the north-east of the India plate and the crimp from Qinghai Tibet Plateau, and it also provides support for the study of crustal stress variation and earthquake prediction in Sichuan Yunnan region.