The China Academy of Space Technology is a Chinese space agency and subordinate of China Aerospace Science and Technology Corporation . It was founded on 20 February 1968 and is the main spacecraft development and production facility in China. On 24 April 1970 CAST successfully launched China's first artificial satellite Dong Fang Hong I. Wikipedia.
China Academy of Space Technology | Date: 2017-01-25
There is provided a system for determining a satellite overall scheme based on multidisciplinary optimization and an implementation method thereof according to the disclosure. The system includes a satellite overall technical index extracting module, a satellite overall technical index allocating module, a satellite subsystem technical index forming module, a satellite system design discipline decomposing module, a design structure matrix generating module, a satellite system discipline analyzing and modeling module, a satellite system optimizing and modeling module, a model simplification module, a two-level collaborative optimizing and modeling module, a collaborative optimizing and solving module, a satellite overall technology index database, a model baseline design database, a design parameter base, and a model library, and a satellite overall scheme parameter outputting module. In the method, the multidisciplinary design optimization of the overall solution of the satellite is achieved by extracting system indexes, decomposing disciplines and design tasks, design discipline analyzing and modeling, structuring a design structure matrix, satellite overall scheme multidisciplinary design optimization representation , model simplification, two-level collaborative optimization modeling and solving.
Wang F.,China Academy of Space Technology |
Huang J.,Chinese University of Hong Kong |
Zhao Y.,Peking University
IEEE Transactions on Wireless Communications | Year: 2012
Supporting the quality of service of unlicensed users in cognitive radio networks is very challenging, mainly due to the dynamic resource availability induced by the licensed users' activities. In this paper, we derive the optimal admission control and channel allocation decisions in cognitive overlay networks to support delay sensitive communications of unlicensed users. We formulate it as a Markov decision process problem, and solve it by transforming the original formulation into a stochastic shortest path problem. We then propose a simple heuristic control policy, which includes a threshold-based admission control scheme and and a largest-delay-first channel allocation scheme, and prove the optimality of the largest-delay-first channel allocation scheme. We further propose an improved policy using the rollout algorithm. By comparing the performance of both proposed policies with the upper-bound of the maximum revenue, we show that our policies achieve close-to-optimal performances with low complexities. © 2012 IEEE.
News Article | November 6, 2015
China successfully launched a new communication satellite called ChinaSat 2C, which will be utilized to provide transmissions for radio, television and broadband services. The satellite was carried on-board the Long March 3B rocket on Wednesday from the Xichang Satellite Launch Center in southwest China's Sichuan province. Launched at 12:25 a.m., the experimental satellite for communication technology will provide signal transmission services for the country's television stations, radio stations, cable networks and wireless transmission devices across China. ChinaSat 2C was developed by China Academy of Space Technology and owned by China Satellite Communications Co., Ltd., a company that provides satellite space segment and satellite ground operation services. Generally, they provide transmissions through in-orbit satellites to broadcast television programs and radio stations. The launch was the 216th mission of the Long March carrier rocket series and 13th successful space launch by China this year. However, reports circulated that the satellite, which they called Zhongxing-2C was launched with a private payload believed by Western observers to be a military communications satellite. They speculated that this newly launched satellite is the second one of the second generation Shentong geostationary military communication satellites. China media did not release other information regarding the mission aside from preflight warnings for airplanes to avoid the area. Lately, a series of satellites for various purposes were launched by China. On Oct. 16, they launched the APSTAR-9 communications satellite which was also blasted off with a Long March-3B/G2 rocket which is the replacement satellite for APT Satellite's APSTAR-9A satellite. It was launched to provide quality satellite telecommunications and broadcasting services to the Asia-Pacific region. On Oct. 27, they launched a mapping satellite into the orbit. Tianhui-1C will be used mainly for scientific experiments, mapping, disaster relief and land resource surveys. A satellite intended to explore the dark matter is scheduled to be launched in December. First of the satellites in that series, the dark matter particle explorer will aid in the assessment of direction and electric charge of energy particles in space to search dark matter.
Li J.,China Academy of Space Technology |
Fang J.,Beihang University
IEEE Transactions on Instrumentation and Measurement | Year: 2013
Inertial sensor errors include deterministic errors and stochastic errors. Deterministic errors can be calibrated in laboratory by simple computation technique. Stochastic errors can be determined during calibration by adopting special methods because of their random character. The simplest method to determine the stochastic errors for inertial sensors is the Allan variance. This kind of method needs large data to fully characterize the stochastic errors. The normal nonoverlapped Allan variance has quite poor estimation accuracy in long cluster time. The fully overlapping Allan variance and traditional total variance have better estimation accuracy in long cluster time but are quite time consuming for large data set. The not fully overlapping Allan variance and nonoverlapped total variance are suitable for large data set to improve the estimation accuracy in long cluster time with much less time, but their accuracy is still relatively poor in comparison with not fully overlapping total variance. Whereas the not fully overlapping total variance is relatively time consuming and, compared with Allan variance, there is a bias which is not easy to be corrected. This paper proposes a sliding average Allan variance that has comparable estimation accuracy with total variance. The data are not required to extend as the total variance; thus the calculation burden could be reduced greatly. Therefore, it is more suitable for large data set. In addition this method has no bias in comparison with Allan variance, which means no bias correction is required. This method is applied to 12-h static data of three gyroscopes from a position and orientation system with good performance. © 2013 IEEE.
News Article | December 26, 2016
Notwithstanding NASA's skepticism about the "reactionless space" engine, China has revealed that is going ahead with a working prototype of EmDrive space propulsion technology, signaling the technology's success. According to reports that quoted China's Ministry of Science and Technology, the "key technology research" has been on for many years and expansion into "engineering applications" is imminent. Announcing the details at a press conference in Beijing, the China Academy of Space Technology (CAST) leaders explained the progress in the ongoing engagement with the EmDrive in which National research institutions have done repeated tests and drew an encouraging response. It was a loud assertion that China is taking the technology forward. "We have successfully developed several specifications of multiple prototype principles. The establishment of an experimental verification platform to complete the milli-level micro thrust measurement test, as well as several years of repeated experiments and investigations into corresponding interference factors, confirm that in this type of thruster, thrust exists," added Chen Yue, China's head of the communication satellite division. Experts said the technology gained good traction and is at a testing stage aboard the Tiangong-2 space laboratory. The liberal funding from China's space agency is making sure that its early incorporation in Chinese satellites is a priority. According to CAST communications satellite designer Li Feng, the prototype has already generated a few millinewtons of thrust. According to the Feng, the agency is aiming to reach higher levels of thrust between 100 millinewtons to 1 newton to garner better control and rule out any collapse of the satellite into the orbit by looking to improve the placement of the thruster on satellites. Noting the innovations ahead, CAST officials said they need to improve the cavity design to cut down electrical losses from the material the cavity is made of and position the microwave thruster to balance the temperature of the cavity for the desired thrust levels. With China testifying to the success of the 'impossible' and 'reactionless' space engine, EmDrive is ahead with a new milestone. The pioneering efforts of British electrical engineer Roger Shawyer in EmDrive through his company Satellite Propulsion Research Ltd are also contested by many scientists. The thruster designed in 2001 was intended for space travel and named Electromagnetic Drive (EmDrive) with an anisotropic electromagnetic field created in the microwave cavity, relying on a directional field to induce movement. However, a section of the scientific community is appalled and says EmDrive is unwieldy as it breaches Newton's third law of motion that says every action would trigger an equal and opposite reaction. In EmDrive's case, fuel ejections are not happening. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Li W.-M.,China Academy of Space Technology |
Liu B.,China Academy of Space Technology |
Zhao H.-W.,China Academy of Space Technology
IEEE Antennas and Wireless Propagation Letters | Year: 2014
The U-shaped structure is presented for designing a dual-band circularly polarized (CP) slot antenna that has a single metallic layer and is fed by a coplanar waveguide (CPW). To evaluate the performance of the versatile structure, a U-slot and a U-strip slot antenna have been designed for 2.6/3.6 and 2.5/3.5 GHz bands application. By employing a Differential Evolution (DE) algorithm to optimize some primary parameters of the proposed antennas, the optimum impedance and axial-ratio bandwidths at the given operating frequency can be achieved without using the trial-and-error method. Prototypes of the two proposed designs were constructed and studied experimentally. The measured results show that the frequency ratio of the upper band to the lower band is 1.4 (3.6/2.6 GHz, 3.5/2.5 GHz) or less. Other characteristics such as impedance bandwidths, axial-ratio bandwidths, radiation patterns, and peak gains will also be presented for design validation. © 2002-2011 IEEE.
Wang L.,China Academy of Space Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016
A graphene passively Q-switched single frequency Ho:YAG laser was demonstrated. Ho:YAG crystal was resonantly pumped by a 1908 nm diode laser. Twisted-mode single frequency technique was applied to realize single frequency oscillation. The maximum single frequency laser output was 358 mW. Single frequency pulse laser output was achieved by inserting a graphene into the single frequency Ho:YAG laser. The maximum average power of 149 mW was obtained with the pulse repetition rate of 40.45 kHz under 8.32 W of incident pump power. © 2016 SPIE.
Li M.,China Academy of Space Technology
62nd International Astronautical Congress 2011, IAC 2011 | Year: 2011
China National Space Administration attaches great importance to the space debris issue. Under the frame of "12 th Five-Year Plan for Space Debris Research", China has arranged several kinds of research programs in the field of space mitigation, such as passivation design for all new-designed launch vehicle orbital stage, after-mission disposal of GEO satellite at end of life-time, after-mission disposal for LEO satellite at end of life-time, standardization of space debris mitigation, development of expert system for space debris mitigation design, and so on. Another important issue is to carry out the "Management Requirement for Space Debris Mitigation and Protection" ratified by China National Space Administration in 2010. With this effort, China space industry will follow the requirements for management and technical issues throughout space activities, which will be of far-reaching influence on China space activities. Copyright ©2011 by the International Astronautical Federation. All rights reserved.
News Article | November 3, 2016
Actively Advances into Cultural Industry by Developing the First Aerospace-Themed Park and Education Base for Science Popularisation in China China Household Holdings Limited ("China Household" or "the Group"; Stock code: 692) is pleased to announce that the Group has entered into a cooperation agreement with Zhongheng Investment Limited ("China Shenzhou Aerospace Park") in relation to the acquisition of the sales shares of Shenzhou Aerospace Town Holdings Company Limited ("Shenzhou Aerospace Town") to actively develop the China Shenzhou Aerospace-Themed Park Tourism Township Project (the "project") and further extend its business into areas of cultural industry. On 31 October, the Group held a grand signing ceremony with Shenzhou Aerospace Town in Zhongshan City, Guangdong, with numerous guests including Mr. Yuan Minhui, Director of Beijing Institute of Space Science and Technology Information, Ms. Wu Yuexia, Vice Mayor of Zhongshan Manicipal Government, government officials at various levels, directors and representatives of China Household and Shenzhou Aerospace Town, together with representatives of various banks, financial institutions and social organisations there to support the development of the project of Shenzhou Aerospace Park and witnessed this important moment. The China Shenzhou Aerospace-Themed Park Tourism Township Project is the first aerospace-themed park and education base for science popularisation in China strategically planned and jointly developed by China Academy of Space Technology (Space Fifth Institute) and the project party. The project has been included in the "Thirteenth Five" key construction projects in Guangdong province in 2016 and in the major construction projects of Zhongshan City in 2016. Located in Shenwan Town, Zhongshan City, Guangdong Province, with a total site area of 800,000 square meters, the project is intended to be developed into a tourism, cultural and commercial estate village integrated with features of themed-tourism plaza, leisure and resort complex and car camping site in three sectors, mainly consisting of seven sub-parks including Shenzhou Aerospace Park, Outlets Town, Space Agricultural Park, Space Experience Tour, Wentian Science Village, Shengshi Flying Club, Weidu Base, with investment amounted to RMB 7 billion. The project is scheduled to start construction next year, and open in 2020, with expectation of an increase of 5 million new tourists and tourism income of RMB 5 billion for Zhongshan City each year. Pursuant to the Memorandum, China Household intends to acquire the sales shares of Shenzhou Aerospace Town at the total consideration of no less than HK$1.45 billion. Specific method and schedule of payment are subject to further negotiation, which may include but not limited to by way of an issuance of consideration shares, convertible bonds and promissory notes. "In recent years, the State has been vigorously promoting tourism and cultural industries, especially laying stress on the development of new aspects of the industry in agricultural tourism, agricultural experience, creative agriculture, tourism real estate and cultural real estate. Meanwhile, the tourism industry accounted for 10.1% of the GDP of China, and has become the new growth driver of the Chinese economy under the new norm. In view of that, the Group is also actively looking for related investment opportunities, to diversify business distribution and revenue sources. As one of the national key development projects, the China Shenzhou Aerospace-Themed Park Tourism Township Project is expected to be a milestone for the Group tapping into the tourism and culture business in China, as well as facilitating its overall promotion and transition and shaping high-end goodwill. Upon the commencement of the cooperation, the project will attract more low-cost capital through the listing platform of the Group, so as to speed up the pace of development. Looking forward, we will seize the development opportunity of China's cultural industry, with China's aerospace-themed park tourism town as a beginning to actively expand our business scope, and strengthen the core competitiveness of the Group so as to generate greater value for shareholders," said Mr. Fu Zhenjun, Executive Director of China Household. About China Household Holdings Limited (Stock Code: 692) Founded in 1975, China Household Holdings Limited (previously "Bao Yuan Holdings Limited") was successfully listed on the Main Board of the Hong Kong Stock Exchange in January 2000. In January 2013, after completing the acquisition of the China Household Holdings Limited and its principal operating company - "Prado Style", the Group successfully marked the completion of major strategic transformation to the home business to provide general one-stop household solution. Currently, the Group engages the sales of products under the brand of "Prado Style Household" and operates an integrated e-commerce platform, China Household Commercial Plaza (http://mall.chh692.com) to provide all-rounded and one-stop solution of home decoration. Media enquiries: One PR Limited Tel: +852 2592 7223 Email:
News Article | April 5, 2016
The Soret Coefficient in Crude Oil experiment will measure how hydrocarbon molecules redistribute when the temperature is not uniform. Learning how complex liquids behave is of interest to the petroleum industry and academia, who can apply the data to model real-life conditions of oil reservoirs deep underground. These measurements can only be performed in weightlessness. Set for launch on China's SJ-10 satellite on 6 April local time, the experiment consists of six sturdy cylinders, each containing just one millilitre of crude oil but compressed up to 500 times normal pressure at sea level on Earth – making it one of the highest-pressure items ever launched into space. Lifting-off from China's Juiquan site in the Gobi desert, the satellite will spend almost two weeks in orbit before it returns to Earth. After landing in Si Chuan province, the team will retrieve the experiment for detailed analysis. The experiment is a partnership between ESA, China's National Space Science Centre, France's Total oil company and China's PetroChina oil company. "The experiment is designed to sharpen our understanding of deep crude oil reservoirs up to 8 km underground," explains Antonio Verga, overseeing the project for ESA. "Imagine a packet of cornflakes – over time the smaller flakes drop to the bottom under gravity. On a molecular scale this experiment is doing something similar but then looking at how temperature causes fluids to rearrange in weightlessness," says ESA's Olivier Minster. "Deep underground, crushing pressure and rising temperature as one goes down is thought to lead to a diffusion effect – petroleum compounds moving due to temperature, basically defying gravity. "Over geological timescales, heavier deposits end up rising, while lighter ones sink. "The aim is to quantify this effect in weightlessness, to make it easier to create computer models of oil reservoirs that will help guide future decisions on their exploitation." The experiment's crude oil sits in six small titanium cylinders. One end of each cylinder is warmed while the other end is cooled. Before returning to Earth, a valve is closed to prevent the liquid from remixing during reentry. Sending such a high-pressure device into space is not to be taken lightly and the cylinders were built to withstand more than double pressure than they will during normal operations – 1000 times atmospheric pressure. A specialist company, Sanchez Technology in France, worked for the prime contractor QinetiQ Space in Belgium. The electronic unit was developed and built by the Shandong Institute of Aerospace Engineering at Yantay. The experiment passed testing with the SJ-10 spacecraft at the China Academy of Space Technology in Beijing, China last year – including thermal cycling to reproduce the extreme changes in temperature the experiment will be subjected to during its orbits of Earth, as well as vibration and shock testing to simulate launch and reentry. Two weeks ago ESA and QinetiQ staff took the 8.5 kg flight unit – about the size of a desktop computer – on a four-day drive to the remote launch site in Gansu province. The experiment with its oil-filled cells is now ready for its journey to space tomorrow. Explore further: From earth to space and back again