The Development of Satellite Communications of China

In this article, Mr. Liu Shen, principal senior engineer, directorate general of Telecommunications, Ministry of Post and Telecommunications, briefly introduces the developments and applications of China's satellite communications , including domestic and international satellite communications.     

The Development of the Chinese Academy of Space Technology

The Chinese Academy of SpaceTechnology (CAST),officiallyfounded on Feb.20,1968,has ahistory of 25 years.Now it is aworld-famous space organizationwith a considerable size.CAST has14 research institutes and factoriesall over the country with more than11 thousand staff and workers in-cluding over 6000 technicians(about 1700 high and middle ranktechnical experts).Now it is spe-cialized in many areas,such asspacecraft system,structure,thermal control,attitude control,orbit control,electronics telemetry,     

Protection of Space Environment

In the early 1960s,with the ad-vent of the space era,it was quick-ly recognized that any object inspace was at risk due to the naturalmeteoroid environment.In the late1960s,it was recognized that the     

Thermal Polymerization of Cyanate Ester-Benzoxazine：Study of a Functional Model Compound

A novel benzoxazine (BOZ) monomer is synthesized by a pot method with solvent-free to blend with cyanate ester (CE). A soluble intermediate is obtained after being cured for 20 h at 80 ℃. The two model compound and the blends are analyzed with the infrared radiation (IR)， nuclear magnetic resonance (NMR) spectroscopy， and differential scanning calorimetry (DSC). The results show that an intermediate of the iminocarbonate and BOZ structures is formed by the ring-open BOZ reacting with the cyanate groups and ring-unopened BOZ. Moreover， rearrangement and ring-opening occur in the postcure of the intermediate to form the alkyl isocyanurate structure with polybenzoxazine.     

The Achievements and the Future of the Development of China's Space Technology

China's space cause is based on the development of missile technology. In the 1950s, new China, which was just founded, decided to keep pace with the jet technology times, to begin developing missile and rocket science and technology, and to establish China's new space scientific and technological industry.     

Effect of thin condensate films of a metal working fluid of an electric propulsion engine on the integral optical coefficients of a spacecraft’s thermal control coating

Materials on experimental studies to determine the effect of thin condensate films of cesium (used as a model working medium for electric propulsion engines and some spacecraft power sources) on integral optical coefficients of spacecraft thermal control coatings are presented. A technique modified by the author and employing the regular thermal regime of a thin metal plate is used. Measurement results demonstrate that films with thicknesses of 100–1000 Å can seriously degrade the integral optical coefficients of thermal control coatings and thus disturb the heat balance of some spacecraft systems.     

Development of China's Space Industry

Broadly speaking,China's spaceindustry includes space technology,space science and space application.The paper mainly covers China'sspace technology. China's space technology indus-try consists of artificial satellites,launch vehicles,launch and recov-     

A Study of the Luminescence of the Lyman–Birge–Hopfield Bands in the Atmospheres of the Earth and Titan

Cosmic Research - Calculations were made of the volume and integral emission intensities of the Lyman–Birge–Hopfield (LBH) bands of molecular nitrogen at 146.4, 138.4, 135.4, and 132.5...     

INTERBALL-1 Observations of the Kilometric “Continuum” of the Earth's Magnetosphere

The electromagnetic radio-frequency emission of the inner region of the Earth's plasmasphere discovered recently by the GEOTAIL satellite [4] and referred to as the kilometric continuum was observed by the INTERBALL-1 satellite (1995–2000) in the 100–500 kHz band in the AKR-X experiment. During a period of low solar activity (1995–1997), this continuum was found leaving the inner plasmasphere at geocentric distances of 2–4R _E as isolated pencil-like (1°–6°) beams located in the magnetic equator plane. During a time of high solar activity (1999–2000), the occurrence of the emission was extremely rare (it was observed only at a considerable fall of this activity). If detected, at the same geocentric distances (2–4R _E) the continuum demonstrated a strongly variable and perturbed character, as well as a considerably larger extension of the beam over the geomagnetic latitude (10°–20° and more). In addition, quasi-periodic (QP) signals, similar to the observed QP emissions of Jupiter, were sometimes detected in this period. The probable nature of the observed features of the kilometric continuum is briefly discussed.     

Influence of simulated high-G on the weld size of aL–lI alloy

Whether welding processes are used on earth or in space, they have the same objective: to obtain defect-free welds. To fully understand the effect of gravity on the weld pool geometry and solidification one should perform experiments within a broad range of gravitational acceleration. High-gravity arc welding experiments were done on Al–Li alloy using the centrifuge called Multi-Gravity Research Welding System (MGRWS). At a high “g” level, buoyancy-driven flow is the dominant force in the weld pool over the Marangoni and the electromagnetic forces. Preliminary results show that the average grain size in the fusion zone at 1g is smaller that at 5g.     

Development of China's Application Satellites

The development of China's space technology has been the focus of the world attention. Since the successful launch of DFH-1 artificial earth satellite on April 24, 1970, China has sent 33 indigenous satellites, including scientific experimental satellites, technical experimental satellites and meteorological satellites. All the experimental and operational satellites have played an important role in the construction of national economy and defense, and provided the advanced prapagation instruments for China's science, culture and education, and people both in cities and countries could watch TV andlisten to the radio and take part in telelecture. This has improved the cultural quality of the whole nation and accelerated the development of the four modernizations.     

The Development and Application of Ground Systems and Derived Systems of Space Technology

In this paper,the development ofsatellite ground systems and non-satellite equipments and systems de-rived from satellite technology inthe Chinese Academy of SpaceTechnology is reviewed.Satelliteground systems include those fortracking,monitoring and controlfor the launch and operation ofsatellites as well as transmitting andreceiving system for dedicated andindividual users.Derived systemsand equipment include some ofspinoff from satellite technologies,such as computer measurement andcontrol,attitude control,thermalcontrol,radio electronic technique,vacuum technique and new materi-als.They are related to the eco-nomic and social benefits derivedfrom the development of space tech-nology.     

Development of China''''s Ocean Satellites

China's first ocean satellite HY-1A was launched by a LM-4B launch vehicle on May 15,2002.The satellite operated normally beyond the two- year design lifetime.An upgraded satellite HY-1B was launched recently on April 11, 2007 by a LM-2C launch vehicle,which is expected to improve the ability for sea water color remote sensing data     

Spin-off of China's Space Technology

Based on the space section of the former Ministry of Aerospace Industry, China Aerospace Corporation was set up in June, 1993. It is a very large nationwide science, technology and industry corporation, which combines the military with civilian technology and industry with trade.     

Development Trend of Space Technology

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Numerical simulation of circulation of the Titan’s atmosphere: Interpretation of measurements of the <Emphasis Type="Italic">Huygens</Emphasis> probe

The results of numerical simulation of the general circulation in the Titan’s atmosphere at heights from 0 to 250 km are presented, obtained using a new model based on numerical solution of complete equations of motion of viscous compressible gas at the temperature distribution given by an empirical model. The model uses no hydrostatic equation and, as compared with traditional models, has higher resolution in vertical and over horizon. The results presented differ from results of other models and agree with the vertical profile of the zonal component of wind velocity measured by the Huygens spacecraft. Interpretation of this profile is given, including its main peculiarity consisting in a nonmonotonic behavior at heights from 60 to 75 km.